ED Decision 2024/003/R CS-ACNS in support of the automatic dependent surveillance-contract extended projected profile (ADS-C EPP) capability — CS-ACNS Issue 5

CS-ACNS Issue 5 — Change Information

Page 1 of 30

CERTIFICATION SPECIFICATIONS,

ACCEPTABLE MEANS OF COMPLIANCE AND

GUIDANCE MATERIAL

FOR

AIRBORNE COMMUNICATIONS, NAVIGATION AND SURVEILLANCE

CS-ACNS ISSUE 5

The European Union Aviation Safety Agency (EASA) publishes Certification specifications, Acceptable

Means of Compliance and Guidance Material for Airborne Communications, Navigation and

Surveillance as consolidated documents. These documents are used for establishing the certification

basis for applications submitted after the date of entry into force of a given issue.

Consequently, except for a note, e.g. ‘[CS-ACNS/5]’, under the amended certification specification (CS), acceptable means of compliance (AMC), or guidance material (GM), the consolidated CS-ACNS Issue 5 (the Annex to ED Decision 2024/003/R) does not allow readers to see the amendments that have been introduced compared to the previous issue. To show the changes, this Change Information document is created, using the following format:

— deleted text is struck through;

— new or amended text is highlighted in blue;

— an ellipsis ‘[…]’ indicates that the rest of the text is unchanged.

Note to the re ade r

In amended, and in particular in existing (that is, unchanged) text, ‘Agency’ is used interchangeably with ‘EASA’. The interchangeable use of these two terms is more apparent in the consolidated versions. Therefore, please note that both terms refer to the ‘European Union Aviation Safety Agency (EASA)’.

CS-ACNS Issue 5 — Change Information

Page 2 of 30

ED Decision 2024/003/R

SUBPART A — GENERAL

[…]

CS ACNS.A.GEN.005 Definitions This point contains the definitions of terms used in CS-ACNS:

[…]

ADS-C refers to automatic dependent surveillance-contract and is a means by which the terms of an ADS-C agreement will be exchanged between the ground system and the aircraft via data link.

[…]

Controller–pilot data link communications (CPDLC) is a data link application that provides a means of communication between the controller and the pilot. the ICAO standardised procedure for Controller- Pilot Data Link Communications. CPDLC takes the form of an application, present on both aircraft and ground-based ATC centres that provides support for the Data Link Communications Initiation Capability (DLIC), ATS communications management service (ACM), ATS Clearance and Information service (ACL) and ATS microphone check service (AMC).

[…]

Emergency indicators refers to specific Mode A Code values: (7500 unlawful interference, 7600 radio failure, 7700 general emergency) or to ADS-C emergency/urgency status (emergency and/or unlawful interference or cancellation of the emergency/urgency).

[…]

Extended projected profile (EPP) provides the aircraft’s trajectory intent using ADS-C.

[…]

[CS-ACNS/5]

CS-ACNS Issue 5 — Change Information

Page 3 of 30

SUBPART B — Communications (COM)

[…]

Section 2 — Data Link Services (DLS) General

CS ACNS.B.DLS.B1.001 Applicability

(See GM1 ACNS.B.DLS.B1.001 and GM2 ACNS.B.DLS.001)

This section provides the airworthiness standards for ATN B1 and ATS B2 limited to the provision of ADS-C EPP with VDL Mode 2 data link aircraft systems to be installed on aircraft intended to be used for CPDLC Communications.

[CS-ACNS/5]

GM1 ACNS.B.DLS.B1001 Applicability

Controller–pilot communications through the data link are used worldwide. Different technologies may be used, and CS ACNS.B.DLS.B1.001 is intended to provide the airworthiness standard for such installations. Additionally, controller–pilot communications over the ATN B1 data link technology have been mandated in Europe through Regulation (EC) No 29/2009. Installations intended to operate within EU airspace, defined in the above-mentioned Regulation, should fully comply with all the requirements of the ‘DATA LINK SERVICES’ section.

Installations not intended to operate within EU airspace are not required to comply with the above-mentioned Regulation.

Note 1: CS ACNS.B.DLS.B1.010 and CS ACNS.B.DLS.B1.015 are also applicable for CPDLC installations where, in addition to ATN B1 over VDL M2, other means of communication and other services are also provided.

Note 2: further background information on data link systems is provided in Appendix B – Background information on data link systems.

ATN B1 data link installations referred to in this section (Section 2) support the data link services ‘ATC Communications Management’ (ACM), ‘ATC Clearances and Information’ (ACL) and ‘ATC Microphone Check’ (AMC) through CPDLC Version 1, as defined in EUROCAE Document ED-110B.

This section also refers to the capability of the data link installations to downlink the extended projected profile (EPP) through ADS-C Version 1, as defined in EUROCAE Document ED-229A, as part of the ATS B2 data link.

The Context Management (CM) application and the DLIC service are prerequisites for the initiation of CPDLC and ADS-C connections.

[CS-ACNS/5]

CS-ACNS Issue 5 — Change Information

Page 4 of 30

GM2 ACNS.B.DLS.001 Applicability

EASA recognises that ATS B2 in accordance with ED-228A and ED-229A (or later acceptable revisions) is the reference application for data link services in the future. EASA will accept and support applications for the approval of systems that offer ATS B2 data link services in lieu of ATN B1 systems. Applicants are encouraged to contact EASA at their earliest convenience to discuss the means to demonstrate compliance with the relevant applicable standards.

[CS-ACNS/5]

CS ACNS.B.DLS.B1.005 Installation Requirements

(See AMC1 ACNS.B.DLS.B1.005 and GM1 ACNS.B.DLS.005)

The data link system includes a means to enable data communication and flight deck annunciations and controls.

[CS-ACNS/5]

AMC1 ACNS.B.DLS.005 Installation Requirements (VDL Mode 2 Sub- Network)

The data link system should comply with ICAO Document 9776 and ARINC 631-6 for VDL Mode 2 multi- frequency operations.

[CS-ACNS/5]

GM1 ACNS.B.DLS.B1.005 Data Link System Installation

An example of installation may be a system comprising the following components or inputs:

— A VHF Data Radio (VDR) with Mode 2 capability and its associated antenna.;

— A Unit for Communication Management with Mode 2 and ATN capabilities.;

— A display unit with means for crew to be notified of ATS Requests and Clearances, and issue downlink crew requests to controllers or responses to outstanding messages (from controllers).;

— An adequate source for UTC time, e.g. a Global Navigation Satellite System (GNSS).;

— An adequate source of information for conducted flight plan information (e.g. Departure Airport, Destination Airport, Estimated Time of Arrival) and trajectory intent, e.g. Flight Management System (FMS);

— An adequate source of aeroplane position, e.g. Flight Management System (FMS), or a Global Navigation Satellite System (GNSS) or both;

— An adequate source for Air/Ground Status information, e.g. an interface with the landing gear or Flight Management System (FMS) or both;

— An adequate aural attention getter for announcements.;

— Adequate indication means of system and service availability.;

— Adequate control means for the crew.

[CS-ACNS/5]

CS-ACNS Issue 5 — Change Information

Page 5 of 30

FLIGHT DECK CONTROL AND INDICATION CAPABILITIES

CS ACNS.B.DLS.B1.010 Flight Deck Interface

(See AMC1 ACNS.B.DLS.B1.010)

(a) A means is provided:

(1) to inform clearly and unambiguously when uplinked messages are received;

(2) for the flight crew to initiate the logon, to terminate the data link services CPDLC connections and to terminate the ADS-C connections;

(3) for the flight crew to know in real time the identifier of the CPDLC ATS provider(s) and the established ADS-C connections connecting with the aircraft;

(4) to display all messages, with minimal flight crew action, in a format that is easy to comprehend and distinguishable from each other;

(5) for the flight crew to respond to ATS messages;

(6) to inform the flight crew that pending or open messages are waiting for a response;

(7) for the flight crew to determine the status of the data link system.;

(b) A means is provided to prohibit the deletion, confirmation, or clearance of a message until the entire message is displayed.

[CS-ACNS/5]

AMC1 ACNS.B.DLS.B1.010 Flight dDeck iInterface

Flight crew control and display of data-link-related information (connectivity status, outstanding messages, etc.) should be consistent with the overall crew flight deck design philosophy.

Flight crew control and display of data link messages should satisfy integrity and interface design criteria appropriate for the intended purpose. Reference to the applicable CS xx.1309 requirements should be observed.

If a direct interface exists between the data link application and other on-board systems, (e.g. flight planning and navigation), a means may be provided for the flight crew to initiate the use of the data contained in the message by the other on-board system. The means provided should be separate from that used to respond to a message.

Flight deck annunciations should be compatible with the overall alerting scheme of the aircraft.

Audible and visual indications should be given by the data link system for each uplinked ATS message, including those messages not displayed immediately because of the lack of crew response to an earlier ATS message. Visual alerts alone may be used for non-ATS messages.

Annunciation of the receipt of a message during critical flight phases should be inhibited until after the critical flight phase. The criteria that define critical flight phases should be consistent with the particular flight deck philosophy and the particular data link services supported.

Means should be provided for the flight crew to list, select, and retrieve the most recent ATS messages received and sent by the flight crew during the flight segment. The status of each message, and the time it was received or sent, should be accessible.

CS-ACNS Issue 5 — Change Information

Page 6 of 30

When CPDLC messages are displayed:

(a) such location should be in the maximum field of view.

(b) messages should be provided in a dedicated display (or in a dedicated window of a display). Shared use of CPDLC and other applications in a common display (or in the same window of a display) should be avoided.

Note 1: (a) and (b) are intended for future extension of CPDLC use beyond the en-route flight phase. Installations not in accordance with these recommendations are liable to be limited for CPDLC operations in the en-route or prior departure flight phase.

Note 2: Where data link messages are displayed on a shared display or on a shared display area, the selection of another display format or function should not result in the loss of uplinked messages which are waiting for a response. In case the pilot is working on another task and a message is uplinked, the uplinked message should not interrupt the current work, nor result in the loss of any uplinked message and/or data entered while accomplishing the other task.

(c) messages from the ATSU (Air Traffic Service Unit) should remain displayed until responded, or cleared, or until the flight crew selects another message.

(d) means should be provided for the flight crew to clear uplinked messages from the display. However, this capability should be protected against inadvertent deletion.

(e) If only part of the message is displayed, a visual indication should be provided to the pilot to indicate the presence of the remaining message.

Means should be provided for the flight crew to create, store, retrieve, edit, delete, and send data link messages.

The data link system should indicate when message storage and/or printing is not available.

A flight deck printer could be used as a means of storing data communications messages received or sent during flight.

If a message intended for visual display is greater than the available display area and only part of the message is displayed, a visual indication is to shall be provided to the pilot to indicate the presence of the remaining message.

Data link messages from the ATS should be displayed and remain displayed until responded, cleared or the flight crew selects another message.

The status of each message (i.e. source, time sent, open/closed) should be displayed together with the message.

[CS-ACNS/5]

CS ACNS.B.DLS.B1.015 Dual Data Link Capabilities (Dual stack)

(See AMC1 ACNS.B.DLS.B1.015)

For aircraft integrating both FANS 1/A and ATN B1 CPDLC applications:

(a) Control and display: Messages with the same intent that are transmitted or received through these technologies are displayed in the same way.

(b) Alerting: Where a common alerting is not demonstrable, a means is provided to distinguish between the alerting schemes in a format that is easy to comprehend.

[CS-ACNS/5]

CS-ACNS Issue 5 — Change Information

Page 7 of 30

AMC1.ACNS.B.DLS.B1.015 Dual Data Link Capabilities (Dual stack)

Note 1: A Ddual stack system is either a bilingual system capable of automatically selecting the data link network or a dual system that uses manual selection with an interlock system.

The data link system should comply with ED-154A, interoperability requirements IR-207, IR-209, IR-210, IR-211, IR-212, IR-214, and IR-215 to ensure seamless transition between two adjacent ATSUs, one using FANS 1/A+ and the other using ATN B1.

The data link system should demonstrate common accessibility to the FANS 1/A and ATN B1 CPDLC applications. Accessibility demonstration should include common controls (i.e. line select keys) or, where different, the potential to introduce confusion or unacceptable flight crew workload should be evaluated.

The data link system should demonstrate common control and input procedures for retrieving and responding to FANS 1/A and ATN B1 uplink messages.

The data link system should demonstrate common control and input procedures for composing and sending FANS 1/A and ATN B1 downlink messages.

The data link system should demonstrate common flight deck indications for incoming FANS 1/A and ATN B1 messages. Where common alerting is not demonstrable, the alerting scheme should be evaluated to ensure that neither confusion nor unnecessary flight crew workload is introduced.

Annunciations and indications should be clear, unambiguous, timely, and consistent with the flight deck philosophy.

FANS 1/A differentiates messages alerting between normal and Urgent. Upon receipt of a high alert CPDLC message, the data link system should indicate it to the flight crew.

Note 2: FANS 1/A standard (ED-100A) identifies the term ‘IMMEDIATELY’, within the phraseology standardised for CPDLC communications. This term is to be understood within the required communications performance scope (RCP) scope, which for oceanic and remote operations is either 240 seconds or 400 seconds. The use of these terms ‘IMMEDIATELY’ and ‘EXPEDITE’ are not to be confused with the terminology used in material related to CS 25.1322. However, annunciations and indications should allow flight crews to easily identify these messages (associated with Urgent and Distress urgency attribute) among the normal messages.

Flight Deck Display of Messages from either FANS 1/A or ATN B1 CPDLC Applications:

A common flight deck display should be capable of displaying messages with the same operational intent resulting from same message elements that may be implemented differently between FANS 1/A and ATN B1 CPDLC applications. The common format to display FANS 1/A messages may be in accordance with the preferred format denoted in Annex A tof ED 122, which is consistent with ICAO Doc 4444, 15th Edition, and ATN B1 message formats.

Dual Stack ATS Data Link System Status Indication:

The system should provide the flight crew with a means to clearly identify the status of different modes of the data link system that affect significantly operational capability. Examples of different modes of data link may include situations wheren downlink messages are available in one airspace, but not the other,; or messages that may or may not be loadable depending on system status, i.e., ATN B1 or FANS 1/A.

ATSU (Air Traffic Service Unit) Connections and Handoffs:

The system should be capable of the following functions:

(1) Proper connection and termination for FANS 1/A ATSU.

CS-ACNS Issue 5 — Change Information

Page 8 of 30

(2) Proper connection and termination for ATN B1 ATSU.

(3) Transfer to next data authority (e.g., FANS 1/A ATSU to ATN B1 ATSU), in both directions. This should include proper connection, maintenance of connection and connection termination protocol to ensure that the aircraft does not hold two simultaneous active CPDLC connections except for the transfer to the next data authority.

(4) Ability for flight crew to manually terminate existing connection and establish new connection, initiate a DLIC ‘logon’ in both directions (i.e., FANS 1/A-to-ATN B1 and ATN B1-to-FANS 1/A).

(5) Ability for flight crew to verify current and next facility designation or name.

Note 3: FAA AC 20-140AC provides adequate guidance related to the application interoperability, sub- networks and performance designators. (refer to Tables 5.1 and 5.2).

[CS-ACNS/5]

CS-ACNS Issue 5 — Change Information

Page 9 of 30

ATN B1 DATA LINK AND ADS-C EPP DOWNLINK CAPABILITY

CS ACNS.B.DLS.B1.020 Data Link Services Capabilities

(See AMC1 ACNS.B.DLS.B1.020, and GM1 ACNS.B.DLS.B1.020 and GM2 ACNS.B.DLS.020)

The data link system provides the following services capabilities:

(a) Data Link Initiation Capability (DLIC);

(b) ATC Communications Management (ACM);

(c) ATC Clearances and Information (ACL); and

(d) ATC Microphone Check (AMC).; and

(e) Downlink of ADS-C EPP.

AMC1 ACNS.B.DLS.B1.020 Data Link Services Capabilities

When the aircraft has no CPDLC Current Data Authority, the aircraft’s data link aircraft equipment should provide crew members that entering an the airspace of a data-link-equipped ATS unit with the capability to initiate a DLIC ‘Logon’ function (e.g. send a CMLogonRequest message) with the applicable ATS unit, in order to identify the aircraft and initiate the use of data link services.

[CS-ACNS/5]

GM1 ACNS.B.DLS.B1.020 Data lLink Services Capabilities

Community Specification EN 303 214 ‘Data Link Services (DLS) System’ provides a set of test scenarios toData link capabilities should be demonstrated using a verifiedrepresentative ground data link system or a ground data link system simulator able to support the transactions and information exchange defined in Subpart B, Section 2.

(a) Data lLink iInitiation cCapability (DLIC) sService

The DLIC service enables the exchange of information between aircraft and ground data link equipment, necessary for the establishment of data link communications.

It ensures:

(1) the unambiguous association of flight data from the aircraft with flight plan data used by an ATS unit;,

(2) the exchange of the supported air–ground application type and version information;,

(3) the delivery of the addressing information of the entity hosting the application.

(b) ATC Communications Management (ACM) Service

The ACM service provides automated assistance to flight crews for conducting the transfer of ATC communications (voice and data).

It includes:

(1) the initial establishment of CPDLC with an ATS unit;

(2) the CPDLC ATC transfer instruction from one ATS unit to the next ATS unit;

CS-ACNS Issue 5 — Change Information

Page 10 of 30

(3) the CPDLC ATC instructions for a change in voice channel;

(4) the normal termination of CPDLC with an ATS unit.

(c) ATC Clearances and Information (ACL) Service

The ACL service provides flight crews with the ability to:

(1) send requests and reports to air traffic controllers;

(2) receive clearances, instructions and notifications issued by air traffic controllers to flight crews.

(d) ATC Microphone Check (AMC) Service

The AMC service provides CPDLC ATC instructions to flight crews(s) requesting him/them to verify the status of his/their voice communication equipment.

(e) Downlink of ADS-C EPP

ADS-C provides the capabilities to:

(1) establish and terminate ADS-C contracts (demand, periodic, event);

(2) downlink the EPP report commensurate with the type of ADS-C contract.

[CS-ACNS/5]

GM2 ACNS.B.DLS.020 Data Link Capabilities — Testing

Testing demonstrations could be based on two main steps:

— Equipment testing (performed by the equipment manufacturer) using adequate simulation testing tools.

— System testing at system test bench and/or at aircraft test level (either on ground or in flight).

Equipment qualification testing data may be reused from the avionics manufacturer, provided that full and unrestricted access to the compliance data is established and maintained. However, the applicant remains responsible for all test data used in the course of compliance demonstration.

[CS-ACNS/5]

CS ACNS.B.DLS.B1.025 Protection mechanism

(See AMC1 ACNS.B.DLS.B1.025 AMC2 ACNS.B.DLS.B1.025 AMC3 ACNS.B.DLS.B1.025, GM1 ACNS.B.DLS.B1.025, GM2 ACNS.B.DLS.B1.025 and GM3 ACNS.B.DLS.B1.025)

A means is provided to protect the integrity of the message.

[CS-ACNS/5]

CS-ACNS Issue 5 — Change Information

Page 11 of 30

AMC1 ACNS.B.DLS.B1.025 Protection mechanism

The data link system should comply that complies with EUROCAE Documents ED-110B and ED-229A following ATN Baseline 1 standards satisfies the requirement.:

— ICAO Document 9705 (Edition 2) for ICS (Sub-Volume V), ULCS (Sub-Volume IV), CM CPDLC (Sub- Volume II) ASE requirements;

— EUROCAE Document ED-110B;

— ICAO Document 9776 and ARINC 631-6 for VDL Mode 2 multi-frequency operations.

The data link aircraft equipment should provide support for the CPDLC application message integrity check mechanism, with support for ‘default checksum algorithm’ only.

[CS-ACNS/5]

AMC2 ACNS.B.DLS.B1.025 Protection mechanism

Testing demonstrations could be based in two main steps:

— Equipment testing (done by equipment manufacturer) using adequate simulation testing tools.

— System testing, at system test bench and/or at aircraft test level (either on ground or in flight).

Equipment qualification testing data may be reused from the avionics manufacturer, provided that full and unrestricted access to the compliance data is established and maintained. However, the applicant remains responsible for all test data used in the course of compliance demonstration.

[CS-ACNS/5]

AMC3 ACNS.B.DLS.B1.025 Protection mechanism

Where ARINC 631-6 identifies a specific deviation from ICAO Doc 9776 (Manual on VDL Mode 2), the provisions of the former should take precedence.

ARINC 631-6 also references ARINC 750 for definition of Signal Quality Parameter (SQP) levels. Measurements of SQP levels may be passed over the air-ground link as parameters in the XID exchanges.

[CS-ACNS/5]

GM1 ACNS.B.DLS.B1.025 Protection mechanism

EUROCAE Document ED-110B sections 3.3.5.1 and 3.3.6 mentions an ‘ATN Message Checksum Algorithm’ (or ‘Application Message Integrity Check (AMIC)’) that does not exist in ICAO Document 9705 Edition 2. These terms are correctly referenced in ICAO Doc 9705 PDR M60050001.

[CS-ACNS/5]

GM2 ACNS.B.DLS.B1.025 Protection mechanism

Both ICAO Document 9705 and EUROCAE Document ED-110B include requirements for the support of FIS and ADS-C applications. These two applications are not mandated for operations in European airspace. Data link aircraft implementations are free to support these applications and should notify their application availability in the DLIC logon function.

[CS-ACNS/5]

CS-ACNS Issue 5 — Change Information

Page 12 of 30

GM3 ACNS.B.DLS.B1.025 Protection mechanism

Further guidance material from EUROCONTROL is available on EUROCONTROL website (www.eurocontrol.int):

— LINK2000+/ATC DATA LINK OPERATIONAL GUIDANCE, Version 6.0, Date: 17 December 2012.

— LINK 2000+ Guidance to Airborne Implementers, Version 1.1, Date: 09 December 2009.

— LINK2000+/FLIGHT CREW DATA LINK OPERATIONAL GUIDANCE Version 5.0, Date: 17 December 2012.

— LINK2000+ Programme, Generic Interop Test Plan for Avionics - Part 1, Upper Layers and CM/CPDLC applications, Version 2.3, Date: 15th June 2010.

[CS-ACNS/5]

CS-ACNS Issue 5 — Change Information

Page 13 of 30

SYSTEM PERFORMANCE REQUIREMENTS

CS ACNS.B.DLS.B1.030 Integrity

The data link system integrity is designed commensurate with a ‘major’ failure condition.

[CS-ACNS/5]

CS ACNS.B.DLS.B1.035 Data LinkS sSystem cContinuity

(See AMC1 ACNS.B.DLS.B1.035 and GM1 ACNS.B.DLS.B1.035)

The data link system is designed to provide a level of continuity that supports the intended operation.

[CS-ACNS/5]

AMC1 ACNS.B.DLS.B1.035 Data LinkS sSystem cContinuity

The loss of the data link system function is considered to be a minor failure condition.

[CS-ACNS/5]

GM1 ACNS.B.DLS.B1.035 Data LinkS sSystem cContinuity

The definition of continuity in CS-ACNS is different from the definition of continuity in EUROCAE Documents ED-120 and ED-228A. Throughout CS-ACNS, continuity (system continuity) refers to ‘the probability that a system will perform its required function without unscheduled interruption’.

In the context of ED-120,this would be commensurate with the term ‘availability’. and ED-228A, ‘continuity’ refers to the probability that the transaction is completed before the transaction expiration time, assuming that the communication system is available when the transaction is initiated.

[CS-ACNS/5]

TIME

CS ACNS.B.DLS.B1.040 Universal Time Coordinated (UTC)

(See AMC1 ACNS.B.DLS.B1.040)

For time synchronisation, a valid UTC time source is used.

Wherever time is utilised in the application of data link communications, it is accurate to within 1 second of UTC.

[CS-ACNS/5]

CS-ACNS Issue 5 — Change Information

Page 14 of 30

AMC1 ACNS.B.DLS.B1.040 Universal Time Coordinated (UTC)

A Global Navigation Satellite System (GNSS) sensor provides an acceptable source of synchronised UTC time.

Time synchronisation is required by ICAO Annex II, chapter 3, section 3.5 as referred by EUROCAE Document ED-110B, section 3.3.2. It is also identified as a safety requirement in EUROCAE Document ED-120 (e.g. SR-ACL-15). [CS-ACNS/5]

DATA LINK INITIATION CAPABILITY (DLIC) SERVICE MESSAGES

CS ACNS.B.DLS.B1.050 DLIC Uplink Messages

(sSee AMC1 ACNS.B.DLS.B1.050)

The data link system is capable of receiving and processing the following messages for the DLIC lLogon and cContact functions:

Function Message

Logon CMLogonResponse

Contact CMContactRequest

[CS-ACNS/5]

AMC1 ACNS.B.DLS.B1.050 DLIC Uplink Messages

The Ddata link system aircraft equipment should comply with ICAO Doc 9705 (Edition 2), section 2.1.4 and EUROCAE Document ED-110B, sSection 2.2.1 or ED-229A, Section 2.4.1.

Note 1: The B1 and B2 CM applications are fully compatible.

Note 2: Although ICAO Doc 9705 is not maintained any more, the DLIC message syntax should comply with ICAO Doc 9705 as referred to in ED-110B.

[CS-ACNS/5]

CS ACNS.B.DLS.B1.055 DLIC Downlink Messages

(sSee AMC1 ACNS.B.DLS.B1.055)

The data link system is capable of sending the following messages for the DLIC lLogon and cContact functions:

Function Message

Logon CMLogonRequest

Contact CMContactResponse

[CS-ACNS/5]

CS-ACNS Issue 5 — Change Information

Page 15 of 30

AMC1 ACNS.B.DLS.B1.055 DLIC Downlink Messages

The Ddata link system aircraft equipment should comply with ICAO Doc 9705 (Edition 2), section 2.1.4 and EUROCAE Document ED-110B, sSection 2.2.1 or ED-229A, Section 2.4.1.

Note 1: The B1 and B2 CM applications are fully compatible.

Note 2: Although ICAO Doc 9705 is not maintained any more, the DLIC message syntax should comply with ICAO Doc 9705 as referred to in ED-110B.

[CS-ACNS/5]

CS ACNS.B.DLS.B1.060 DLIC initiation when in ‘CPDLC inhibited’ state (uplink)

When the data link system is in the ‘CPDLC inhibited’ state, a DLIC Contact Request is processed but the system remains in the ‘CPDLC inhibited’ state.

[CS-ACNS/5]

CPDLC MESSAGES

CS ACNS.B.DLS.B1.070 CPDLC uUplink mMessages

(See AMC1 ACNS.B.DLS.B1.070, GM1 ACNS.B.DLS.B1.070 and GM2 ACNS.B.DLS.B1.070)

The data link system is capable of receiving, processing and displaying the following message elements:

ID Message

UM0 UNABLE

UM1 STANDBY

UM3 ROGER

UM4 AFFIRM

UM5 NEGATIVE

UM19 MAINTAIN [level]

UM20 CLIMB TO [level]

UM23 DESCEND TO [level]

UM26 CLIMB TO REACH [level] BY [time]

UM27 CLIMB TO REACH [level] BY [position]

UM28 DESCEND TO REACH [level] BY [time]

UM29 DESCEND TO REACH [level] BY [position]

UM46 CROSS [position] AT [level]

UM47 CROSS [position] AT OR ABOVE [level]

UM48 CROSS [position] AT OR BELOW [level]

UM51 CROSS [position] AT [time]

UM52 CROSS [position] AT OR BEFORE [time]

UM53 CROSS [position] AT OR AFTER [time]

UM54 CROSS [position] BETWEEN [time] AND [time]

UM55 CROSS [position] AT [speed]

UM61 CROSS [position] AT AND MAINTAIN [level] AT [speed]

CS-ACNS Issue 5 — Change Information

Page 16 of 30

UM64 OFFSET [specifiedDistance] [direction] OF ROUTE

UM72 RESUME OWN NAVIGATION

UM74 PROCEED DIRECT TO [position]

UM79 CLEARED TO [position] VIA [routeClearance]

UM80 CLEARED [routeClearance]

UM82 CLEARED TO DEVIATE UP TO [specifiedDistance] [direction] OF ROUTE

UM92 HOLD AT [position] AS PUBLISHED MAINTAIN [level]

UM94 TURN [direction] HEADING [degrees]

UM96 CONTINUE PRESENT HEADING

UM106 MAINTAIN [speed]

UM107 MAINTAIN PRESENT SPEED

UM108 MAINTAIN [speed] OR GREATER

UM109 MAINTAIN [speed] OR LESS

UM116 RESUME NORMAL SPEED

UM117 CONTACT [unitname] [frequency]

UM120 MONITOR [unitname] [frequency]

UM123 SQUAWK [code]

UM133 REPORT PRESENT LEVEL

UM148 WHEN CAN YOU ACCEPT [level]

UM157 CHECK STUCK MICROPHONE [frequency]

UM159 ERROR [errorInformation]

UM162 SERVICE UNAVAILABLE

UM165 THEN

UM171 CLIMB AT [verticalRate] MINIMUM

UM172 CLIMB AT [verticalRate] MAXIMUM

UM173 DESCEND AT [verticalRate] MINIMUM

UM174 DESCEND AT [verticalRate] MAXIMUM

UM179 SQUAWK IDENT

UM183 [freetext]

UM190 FLY HEADING [degrees]

UM196 [freetext]

UM203 [freetext]

UM205 [freetext]

UM211 REQUEST FORWARDED

UM213 [facilitydesignation] ALTIMETER [altimeter]

UM215 TURN [direction] [degrees]

UM222 NO SPEED RESTRICTION

UM231 STATE PREFERRED LEVEL

UM232 STATE TOP OF DESCENT

UM237 REQUEST AGAIN WITH NEXT UNIT

The data link system is capable of receiving and processing the following message elements:

UM160 NEXT DATA AUTHORITY [facility]

UM227 LOGICAL ACKNOWLEDGEMENT

[CS-ACNS/5]

CS-ACNS Issue 5 — Change Information

Page 17 of 30

AMC1 ACNS.B.DLS.B1.070 CPDLC uUplink mMessages

The data link system should comply with EUROCAE Document ED-110B, Section 2.2.3, and with the CPDLC message syntax in ICAO Doc 9705 (Edition 2), Part I, Section 2.1.4.

Note: Although ICAO Doc 9705 is not maintained any more, the CPDLC message syntax should comply with ICAO Doc 9705 as referred to in ED-110B.

The data link system should prepare the appropriate response downlink message to a received uplink message in compliance with EUROCAE Document ED-110B, Section 2.2.3.3, Table 2-4. Received uplink messages with the response type ‘A/N’ indicated in the ‘Response’ column should be responded to with either DM2 (STANDBY), DM4 (AFFIRM) or DM5 (NEGATIVE). Received uplink messages with the response type ‘R’ indicated in the ‘Response’ column should be responded to with either DM2 (STANDBY), DM3 (ROGER) or DM1 (UNABLE).

The aircraft data link system should also handle unsupported messages (i.e. uplink messages not referenced in CS ACNS.B.DLS.B1.050070) as specified in EUROCAE Document ED-110B, Section 3.3.7.6.

[CS-ACNS/5]

CS-ACNS Issue 5 — Change Information

Page 18 of 30

GM1 ACNS.B.DLS.B1.070 Uplink Messages

The following table associates uplink CPDLC messages to the data link services.

ID Message ACM ACL AMC

UM0 UNABLE x

UM1 STANDBY x

UM3 ROGER x

UM4 AFFIRM x

UM5 NEGATIVE x

UM19 MAINTAIN [level] x

UM20 CLIMB TO [level] x

UM23 DESCEND TO [level] x

UM26 CLIMB TO REACH [level] BY [time] x

UM27 CLIMB TO REACH [level] BY [position] x

UM28 DESCEND TO REACH [level] BY [time] x

UM29 DESCEND TO REACH [level] BY [position] x

UM46 CROSS [position] AT [level] x

UM47 CROSS [position] AT OR ABOVE [level] x

UM48 CROSS [position] AT OR BELOW [level] x

UM51 CROSS [position] AT [time] x

UM52 CROSS [position] AT OR BEFORE [time] x

UM53 CROSS [position] AT OR AFTER [time] x

UM54 CROSS [position] BETWEEN [time] AND [time] x

UM55 CROSS [position] AT [speed] x

UM61 CROSS [position] AT AND MAINTAIN x

UM64 OFFSET [specifiedDistance] [direction] OF ROUTE x

UM72 RESUME OWN NAVIGATION x

UM74 PROCEED DIRECT TO [position] x

UM79 CLEARED TO [position] VIA [routeClearance] x

UM80 CLEARED [routeClearance] x

UM82 CLEARED TO DEVIATE UP TO [specifiedDistance] [direction] OF ROUTE

x

UM92 HOLD AT [position] AS PUBLISHED MAINTAIN [level] x

UM94 TURN [direction] HEADING [degrees] x

UM96 CONTINUE PRESENT HEADING x

UM106 MAINTAIN [speed] x

UM107 MAINTAIN PRESENT SPEED x

UM108 MAINTAIN [speed] OR GREATER x

UM109 MAINTAIN [speed] OR LESS x

UM116 RESUME NORMAL SPEED x

UM117 CONTACT [unitname] [frequency] x

UM120 MONITOR [unitname] [frequency] x

UM123 SQUAWK [code] x

UM133 REPORT PRESENT LEVEL x

UM148 WHEN CAN YOU ACCEPT [level] x

UM157 CHECK STUCK MICROPHONE [frequency] x

UM159 ERROR [errorInformation] x x

UM160 NEXT DATA AUTHORITY [facility] x

CS-ACNS Issue 5 — Change Information

Page 19 of 30

UM162 SERVICE UNAVAILABLE x

UM165 THEN x

UM171 CLIMB AT [verticalRate] MINIMUM x

UM172 CLIMB AT [verticalRate] MAXIMUM x

UM173 DESCEND AT [verticalRate] MINIMUM x

UM174 DESCEND AT [verticalRate] MAXIMUM x

UM179 SQUAWK IDENT x

UM183 [freetext] x x x

UM190 FLY HEADING [degrees] x

UM196 [freetext] x

UM203 [freetext] x

UM205 [freetext] x

UM211 REQUEST FORWARDED x

UM213 [facilitydesignation] ALTIMETER [altimeter] x

UM215 TURN [direction] [degrees] x

UM222 NO SPEED RESTRICTION x

UM227 LOGICAL ACKNOWLEDGEMENT x x

UM231 STATE PREFERRED LEVEL x

UM232 STATE TOP OF DESCENT x

UM237 REQUEST AGAIN WITH NEXT UNIT x x

[CS-ACNS/5]

GM2 ACNS.B.DLS.B1.070 Uplink Messages

The above ACL messages correspond to the common subset of ACL messages defined in EUROCAE Document ED-120, Ssection 5.2.1.1.5 as required by Regulation (EC) No 29/2009.

[CS-ACNS/5]

CS ACNS.B.DLS.B1.075 CPDLC dDownlink mMessages

(See AMC1 ACNS.B.DLS.B1.075, GM1 ACNS.B.DLS.B1.075, GM2 ACNS.B.DLS.B1.075 and GM3 ACNS.B.DLS.B1.075)

The data link system is capable of preparing and sending the following downlink message elements:

ID Message

DM0 WILCO

DM1 UNABLE

DM2 STANDBY

DM3 ROGER

DM4 AFFIRM

DM5 NEGATIVE

DM6 REQUEST [level]

DM18 REQUEST [speed]

DM22 REQUEST DIRECT TO [position]

DM32 PRESENT LEVEL [level]

DM62 ERROR [errorInformation]

DM63 NOT CURRENT DATA AUTHORITY

CS-ACNS Issue 5 — Change Information

Page 20 of 30

DM65 DUE TO WEATHER

DM66 DUE TO AIRCRAFT PERFORMANCE

DM81 WE CAN ACCEPT [level] AT [time]

DM82 WE CANNOT ACCEPT [level]

DM98 [freetext]

DM99 CURRENT DATA AUTHORITY

DM100 LOGICAL ACKNOWLEDGEMENT

DM106 PREFERRED LEVEL [level]

DM107 NOT AUTHORISZED NEXT DATA AUTHORITY

DM109 TOP OF DESCENT [time]

[CS-ACNS/5]

AMC1 ACNS.B.DLS.B1.075 Downlink mMessages

The data link system should comply with EUROCAE Document ED-110B, Section 2.2.3, and with the CPDLC message syntax in ICAO Doc 9705 (Edition 2), Section 2.1.4.

Note: Although ICAO Doc 9705 is not maintained any more, the CPDLC message syntax should comply with ICAO Doc 9705 as referred to in ED-110B.

The data link aircraft equipment system should prepare the appropriate response downlink message response to a received uplink message in compliance with EUROCAE Document ED-110B, Section 2.2.3.3, Table 2-4.

[CS-ACNS/5]

GM1 ACNS.B.DLS.B1.075 Downlink mMessages

The following table associates downlink messages with data link services.

ID Message ACM ACL AMC

DM0 WILCO x x

DM1 UNABLE x x

DM2 STANDBY x x

DM3 ROGER x

DM4 AFFIRM x

DM5 NEGATIVE x

DM6 REQUEST [level] x

DM18 REQUEST [speed] x

DM22 REQUEST DIRECT TO [position] x

DM32 PRESENT LEVEL [level] x

DM62 ERROR [errorInformation] x x

DM63 NOT CURRENT DATA AUTHORITY x

DM65 DUE TO WEATHER x

DM66 DUE TO AIRCRAFT PERFORMANCE x

DM81 WE CAN ACCEPT [level] AT [time] x

DM82 WE CANNOT ACCEPT [level] x

DM98 [freetext] x x

DM99 CURRENT DATA AUTHORITY x

DM100 LOGICAL ACKNOWLEDGEMENT x x

CS-ACNS Issue 5 — Change Information

Page 21 of 30

DM106 PREFERRED LEVEL [level] x

DM107 NOT AUTHORIZSED NEXT DATA AUTHORITY x x

DM109 TOP OF DESCENT [time] x

[CS-ACNS/5]

GM2 ACNS.B.DLS.B1.075 Downlink Messages

The above ACL messages correspond to the common subset of ACL messages defined in EUROCAE Document ED-120, Ssection 5.2.1.1.5 as required by Regulation (EC) No 29/2009.

[CS-ACNS/5]

GM3 ACNS.B.DLS.B1.075 Optional ACL Downlink Messages

The data link system may also allow the sending the following ACL messages defined in EUROCAE Document ED-120, sSection 5.2.1.1.5. The message syntax should also comply with ICAO Doc 9705 (Edition 2), section 2.3.4.

Note 1: Although ICAO Doc 9705 is not maintained any more, the CPDLC message syntax should comply with ICAO Doc 9705 as referred to in ED-110B.

ID Message

DM9 REQUEST CLIMB TO [level]

DM10 REQUEST DESCENT TO [level]

DM27 REQUEST WEATHER DEVIATION UP TO [specifiedDistance] [direction] OF ROUTE

Note 2: To prevent costly retrofitting, implementation of the above optional messages is highly recommended.

[CS-ACNS/5]

ADS-C EPP DATA

CS ACNS.B.DLS.077 ADS-C EPP Data

(See AMC1 ACNS.B.DLS.077)

The data link system is capable of:

— receiving and processing ADS-C contract requests (demand, periodic, event); and

— preparing and downlinking EPP through ADS-C contract reports according to the ADS-C contract requests.

[CS-ACNS/5]

CS-ACNS Issue 5 — Change Information

Page 22 of 30

AMC1 ACNS.B.DLS.077 ADS-C EPP Data

The data link system should comply with EUROCAE Document ED-228A, Section 6.2 and EUROCAE ED-229A, Sections 3.2 and 5.3 to support the exchange of EPP data.

[CS-ACNS/5]

DATA LINK SERVICES AND ADS-C EPP DOWNLINK REQUIREMENTS

CS ACNS.B.DLS.B1.080 Data lLink iInitiation cCapability (DLIC) sService

(See AMC1 ACNS.B.DLS.B1.080 and GM1 ACNS.B.DLS.B1.080)

The data link system for DLIC service compliesconforms with Section 4.1, 4.2.2 and 4.3.2 of EUROCAE Documents ED-120 ‘Safety and Performance Requirements Standard For Initial Air Traffic Data Link Services In Continental Airspace’, Sections 4.1, 4.2.2 and 4.3.2, and Sections 2.2.1 and 4.1 of EUROCAE Document ED-110B ‘Interoperability Requirements Standard for Aeronautical Telecommunication Network Baseline 1’, Sections 2.2.1 and 4.1.

[CS-ACNS/5]

AMC1 ACNS.B.DLS.B1.080 Data Link Initiation Capability (DLIC) Service

(a) The data link aircraft equipment DLIC lLogon function should comply with the aircraft system PR-DLIC-Init-ETRCTP and PR-DLIC-Init-TT performance values, respectively 6 seconds and 4 seconds, as specified in EUROCAE Document ED-120 Table A-3.

(b) The data link aircraft equipment DLIC cContact function should comply with the aircraft system PR-DLIC-Cont-ETRCTP and PR-DLIC-Cont-TT performance values, respectively 12 seconds and 8 seconds, as specified in EUROCAE Document ED-120 Table A-3.

(c) The data link system should:

(1) not permit data link services when there are incompatible DLIC version numbers;

(2) reinitiate the service with the applicable ATSUs when any of the application or flight information changes;

(3) insert the relevant initiation data in the initiation messages;

(4) not affect the intent of the DLIC message during processing (data entry/encoding/ transmitting/decoding/displaying).

[CS-ACNS/5]

CS-ACNS Issue 5 — Change Information

Page 23 of 30

GM1 ACNS.B.DLS.B1.080 Data Link Initiation Capability (DLIC) Service

The Performance Tables in the main body of EUROCAE Document ED-120 for DLIC service (Table 4-8 and Table 4-9), ACM (Table 5-21) and ACL (Table 5-31 and Table 5-32) provide the allocated values for the required transaction performance.

A detailed allocation for Aaircraft delays is provided in EUROCAE Document ED-120 Annex A Table A-3.

[CS-ACNS/5]

CS ACNS.B.DLS.B1.085 ATC cCommunications mManagement (ACM) sService(See AMC1 ACNS.B.DLS.B1.085 and GM1 ACNS.B.DLS.B1.085)

The data link system for ACM service compliesconforms with Section 5.1.1, 5.1.2.3 (excluding requirements relating to downstream clearance) and 5.1.3.2 of EUROCAE Document ED-120 ‘Safety and Performance Requirements Standard For Initial Air Traffic Data Link Services In Continental Airspace’, Sections 5.1.1, 5.1.2.3 (excluding the requirements relating to downstream clearance) and 5.1.3.2.

[CS-ACNS/5]

AMC1 ACNS.B.DLS.B1.085 ATC Communications Management (ACM) Service

The data link system for ACM service should comply with the aircraft system PR-ACM-ETRCTP and PR-ACM-TT performance values, respectively 6 seconds and 4 seconds, as specified in EUROCAE Document ED-120 Annex A Table A-3.

[CS-ACNS/5]

GM1 ACNS.B.DLS.B1.085 ATC Communications Management (ACM) Service

The Performance Tables in the main body of EUROCAE Document ED-120 for DLIC (Table 4-8 and Table 4-9), ACM service (Table 5-21) and ACL (Table 5-31 and Table 5-32 provide the allocated values for the required transaction performance.

A detailed allocation for Aaircraft delays is provided in EUROCAE Document ED-120 Annex A/ Table A-3.

[CS-ACNS/5]

CS ACNS.B.DLS.B1.090 ACL sService sSafety rRequirements

(See AMC1 ACNS.B.DLS.B1.090 and GM1 ACNS.B.DLS.B1.090)

The data link system for ACL service compliesconforms with Section 5.2.1, 5.2.2.3 and 5.2.3.2 of EUROCAE Document ED-120, ‘Safety and Performance Requirements Standard For Initial Air Traffic Data Link Services In Continental Airspace’ Sections 5.2.1, 5.2.2.3 and 5.2.3.2.

[CS-ACNS/5]

CS-ACNS Issue 5 — Change Information

Page 24 of 30

AMC1 ACNS.B.DLS.B1.090 ATC Clearances and Information (ACL) Service

The data link system for ACL service should comply with the aircraft system PR-ACL-ETRCTP and PR-ACL-TT performance values, respectively 6 seconds and 4 seconds, as specified in EUROCAE Document ED-120 Annex A Table A-3.

[CS-ACNS/5]

GM1 ACNS.B.DLS.B1.090 ATC Clearances and Information (ACL) Service

The Performance Tables in the main body of EUROCAE Document ED-120 for DLIC (Table 4-8 and Table 4-9), ACM (Table 5-21) and ACL service (Table 5-31 and Table 5-32) provide the allocated values for the required transaction performance.

A detailed allocation for Aaircraft delays is provided in EUROCAE Document ED-120 Annex A Table A-3.

[CS-ACNS/5]

CS ACNS.B.DLS.B1.095 ATC mMicrophone cCheck (AMC) sService

The data link system for AMC service compliesconforms with EUROCAE Document ED-120, Sections 5.3.1, 5.3.2.3 and 5.3.3.2 of EUROCAE Document ‘ED-120 Safety and Performance Requirements Standard For Initial Air Traffic Data Link Services in Continental Airspace’.

[CS-ACNS/5]

CS ACNS.B.DLS.097 ADS-C EPP Safety and Performance Requirements

(See AMC1 ACNS.B.DLS.097)

The data link system for ADS-C EPP complies with EUROCAE Document ED-228A, Sections 6.1, 6.3.1 and 6.3.2.

[CS-ACNS/5]

AMC1 ACNS.B.DLS.097 ADS-C EPP Safety and Performance Requirements

The required surveillance performance (RSP) 160 should apply, in accordance with the intended use of ADS-C EPP within the SES.

[CS-ACNS/5]

CS-ACNS Issue 5 — Change Information

Page 25 of 30

INTEROPERABILITY REQUIREMENTS

CS ACNS.B.DLS.B1.100 Network Layer Requirements

(See AMC1 ACNS.B.DLS.B1.100 and GM1 ACNS.B.DLS.B1.100)

The ATN Router conforms to Class 6 with the capability to support Iinter-domain routing protocol (IDRP).

[CS-ACNS/5]

AMC1 ACNS.B.DLS.B1.100 Network Layer Requirements

The ATN Router should comply with ICAO Document 9705 (Edition 2), Ssections 5.2.4.1, and 5.2.4.3, with an IDRP Hold Time value of 900 seconds.

[CS-ACNS/5]

GM1 ACNS.B.DLS.B1.100 Network Layer Requirements

Compression Schemes

Airborne ATN Routers may implement several distinct, yet complementary, compression schemes.

Airborne ATN Routers should support the CLNP Header Compression (also known as ‘LREF Compression’). Other compression schemes in ICS are optional.

In addition to the CLNP Header Compression, data link ATN Routers that claims support for optional DEFLATE compression should also support ICAO PDU M0070002 (‘Interoperability impact when deflate compression is used. Non-compliance with Zlib’).

[CS-ACNS/5]

CS ACNS.B.DLS.B1.105 Transport Layer Protocol Requirements

(See AMC1 ACNS.B.DLS.B1.105 and GM1 ACNS.B.DLS.B1.105)

The ATN Connection Oriented Transport Protocol (COTP) conforms to Transport Protocol Class 4.

[CS-ACNS/5]

CS-ACNS Issue 5 — Change Information

Page 26 of 30

AMC1 ACNS.B.DLS.B1.105 Transport Layer Protocol Requirements

The ATN End System of the data link aircraft equipment should comply with the Transport Protocol Class 4 specified in ICAO Document 9705 (Edition 2), Sub-volume V, Ssection 5.5.2.

The data link aircraft equipment should implement Transport Protocol Class 4 parameter settings in accordance with the following table:

Scope Parameter Definition Value

Inactivity Inactivity time (I) A bound for the time after which a transport entity will, if it does not receive a Transport Protocol Data Unit (TPDU), initiate the release procedure to terminate the transport connection.

360 seconds sec

Re-Retransmission Retransmission time (T1)

A bound for the maximum time the transport entity will wait for acknowledgement before re- retransmitting a TPDU. The retransmission time is adaptive.

Initial value 30 seconds sec

Maximum Retransmission (N)

Maximum number of TPDU retransmissions. 7

Window Window time (W) A bound for the maximum time a transport entity will wait before retransmitting up-to- date window information.

120 seconds sec

Flow Control Local Acknowledgement delay (Al)

A bound for the maximum time which can elapse between the receipt of a TPDU by the local transport entity from the network layer and the transmission of the corresponding acknowledgement.

1 second sec

[CS-ACNS/5]

GM1 ACNS.B.DLS.B1.105 Transport Layer Protocol Requirements

Transport Protocol Classes

ICAO Doc 9705 (Edition 2), Sub-volume V, Ssection 5.5 identifies both Connection-Oriented and Connection-Less Transport Protocols (as specified in, respectively, ISO/IEC 8073 for COTP and ISO/IEC 8602 for CLTP respectively). The only mandated support is for COTP (i.e. CLTP support is not required).

In addition, ISO/IEC 8073 identifies 5five distinct possible implementations for COTP support, ranging from Class 0 (the less constraining to implement, but also the less reliable) to Class 4 (most reliable). The fifth Cclass, i.e. COTP Class 4 (also known as ’‛TP4’), is the only mandated implementation (all other implementations classes are useless for the ATN COTP support).

Transport Protocol Classes

In the ATN Baseline 1 SARPsS (i.e. ICAO Doc 9705 (Edition 2)), the Transport Class 4 - as — also known as ‘TP4’ —- is as specified in ISO 8073, that mandates support for a 16-bits checksum. Such checksum is considered to be insufficient to detect, and thus compensate, all potential miss deliveries of CLNP Packets by the underlying network routers. The analysis that concluded of TP4 inability to detect and compensate all CLNP miss deliveries is available in ICAO PDR M00040002. The use of a 32-bits long checksum is identified as a solution to address this potential issue.

[CS-ACNS/5]

CS-ACNS Issue 5 — Change Information

Page 27 of 30

CS ACNS.B.DLS.B1.110 Session Layer Requirements(See AMC1

ACNS.B.DLS.B1.110)

The ATN Session protocol is capable of supporting the following session protocol data units (SPDUs):

Abbreviation Full SPDU Name

SCN Short Connect

DRPSAC Short Accept

SACC Short Accept Continue

SRF Short Refuse

SRFC Short Refuse Continue

[CS-ACNS/5]

AMC1 ACNS.B.DLS.B1.110 Session Layer Requirements

(a) The ATN End System of the data link aircraft equipment should support a Session Protocol as specified in ICAO Doc 9705 (Edition 2), Sub-volume IV, Ssection 4.4 including the ISO/IEC 8327 Technical Corrigendum 1 (2002), listed in the following table.

Value (Hex) Abbreviation Full SPDU Name

E8 SCN Short Connect

F0 SAC Short Accept

D8 SACC Short Accept Continue

E0-E3 SRF Short Refuse E0: TC retained, transient refusal E1: TC retained, persistent refusal E2: TC released, transient refusal E3: TC released, persistent refusal

A0 SRFC Short Refuse Continue

(b) The ATN End System Session Protocol of the data link system should make use of the value ‘E3’ to encode the Short Refuse (SRF) SPDU.

[CS-ACNS/5]

CS ACNS.B.DLS.B1.115 Presentation lLayer rRequirements

(See AMC1 ACNS.B.DLS.B1.115)

The ATN Presentation protocol is capable of supporting the presentation protocol data units (PPDUs) listed in the following table:

Abbreviation Full PPDU Name

SHORT-CP Short Presentation Connect, unaligned PER

SHORT-CPA Short Presentation Connect Accept, unaligned PER

SHORT-CPR Short Presentation Connect Reject

[CS-ACNS/5]

CS-ACNS Issue 5 — Change Information

Page 28 of 30

AMC1 ACNS.B.DLS.B1.115 Presentation Layer Requirements

(a) The ATN End System of the data link aircraft equipment should support a Presentation Protocol as specified in ICAO Doc 9705 (Edition 2), Sub-Vvolume IV, Ssection 4.5, and listed in the following table:

Value (Hex) Abbreviation Full PPDU Name

02 SHORT-CP Short Presentation Connect, unaligned PER

02 SHORT-CPA Short Presentation Connect Accept, unaligned PER

x2 SHORT-CPR Short Presentation Connect Reject Where x = reason code: 02: presentation-user 12: reason not specified (transient) 22: temporary congestion (transient) 32: local limit exceeded (transient) 42: called presentation address unknown (permanent) 52: protocol version not supported (permanent) 62: default context not supported (permanent) 72: user data not readable (permanent)

(b) The ATN End System Presentation Protocol of the aircraft’s data link aircraft equipment should make use of the value ‘02’ to encode the SHORT-CPR PPDU.

[CS-ACNS/5]

CS ACNS.B.DLS.B1.120 Application Layer Requirements

(See AMC1 ACNS.B.DLS.B1.120 and GM1 ACNS.B.DLS.B1.120)

The Application Layer is application-independent (also known as ‘Layer 7a’), and is composed of a Convergence Control Function supporting operations of an Application Control Service Element (ACSE).

[CS-ACNS/5]

AMC1 ACNS.B.DLS.B1.120 Application Layer Requirements

(a) The ATN End System of the data link system should support an ATN Control Convergence Function compliant with ICAO Doc 9705 (Edition 2), Sub-Vvolume IV, Ssection 4.3.

(b) The ATN End System of the data link system should support an ATN Association Control Service Element (ACSE) compliant with ICAO Doc 9705 (Edition 2), Sub-Vvolume IV, Ssection 4.6.

[CS-ACNS/5]

GM1 ACNS.B.DLS.B1.120 Application Layer Requirements

From an OSI perspective, the ATN Application lLayer is composed of three distinct parts:

— Layer 7a, that which includes all application-independent services (ControlConvergence Function + ACSE).

— Layer 7b, that which includes all application-dependent service elements (such as the CPDLC- ASE).

CS-ACNS Issue 5 — Change Information

Page 29 of 30

— Layer 7c, that which includes applications (such as the CPDLC application, that which uses CPDLC-ASE for its communications with ground-based systems).

[CS-ACNS/5]

CS ACNS.B.DLS.B1.125 Database

(See GM1 ACNS.B.DLS.125)

The Network Service Access Point (NSAP) address database is capable of being updated.

[CS-ACNS/5]

GM1 ACNS.B.DLS.125 Database

The Network Service Access Point (NSAP) address database is subject to regular update in accordance with ICAO EUR Doc 028.

[CS-ACNS/5]

APPENDICES

Appendix A — Background information on voice communication systems

[…]

Appendix B – Background information on data link systems

(iv) General

This appendix provides additional references, background information, and guidance for maintenance testing, as appropriate to Data Link System installations.

(b) Related references

(1) ICAO

i. ICAO Doc 4444 Air Traffic Management 15th Ed 2007

ii. ICAO Doc 9705 MANUAL OF TECHNICAL PROVISIONS FOR THE AERONAUTICAL TELECOMMUNICATION NETWORK (ATN) 2nd Ed 1999

iii. ICAO Doc 9776 Manual on VHF Digital Link (VDL) Mode 2 1st Ed 2001.

(2) ARINC

Specification 631-6 Guidelines for Design Approval of Aircraft Data Link Communication Systems Supporting Air Traffic Services (ATS) dated 11/2010

(3) FAA

AC 20-140B Guidelines for Design Approval of Aircraft Data Link Communication Systems Supporting Air Traffic Services (ATS) dated 27/09/2012

(4) EUROCONTROL

CS-ACNS Issue 5 — Change Information

Page 30 of 30

i. LINK2000+/ATC DATA LINK OPERATIONAL GUIDANCE, Version 6.0, Date: 17 December 2012.

ii. LINK 2000+ Guidance to Airborne Implementers, Version 1.1, Date: 09 December 2009.

iii. LINK2000+/FLIGHT CREW DATA LINK OPERATIONAL GUIDANCE Version 5.0, Date: 17 December 2012.

iv. LINK2000+ Programme, Generic Interop Test Plan for Avionics – Part 1, Upper Layers and CM/CPDLC applications, Version 2.3, Date: 15th June 2010.

(5) ISO/IEC

i. Document 8073 Information technology – Open Systems Interconnection – Protocol for providing the connection-mode transport service Edition 4,0 including amendment 1 dated 09/1998

ii. Document 8602 Information technology – Protocol for providing the OSI connectionless-mode transport service Edition 2,0 including amendment 1 dated 12/1996

iii. ISO/IEC 8327-1:1996 Information technology — Open Systems Interconnection — Connection-oriented Session protocol: Protocol specification TECHNICAL CORRIGENDUM 1 Published 15/05/2002

(6) EUROCAE

i. ED-110B, December 2007, ‘Interoperability Requirements Standard for Aeronautical Telecommunication Network Baseline 1’ (Interop ATN B1),

ii. ED-120, May 2004, ‘Safety and Performance Requirements Standard For Initial Air Traffic Data Link Services In Continental Airspace (SPR IC)’. Including change 1, change 2, and change 3.

iii. ED-122 February 2011 Safety and Performance Standard for Air Traffic Data Link Services in Oceanic and Remote Airspace (Oceanic SPR Standard)

iv. ED-154A March 2012 Future Air Navigation System 1/A (FANS 1/A) – Aeronautical Telecommunications Network (ATN) Interoperability Standard

[CS-ACNS/5]

Annex to ED Decision 2024/003/R Page 1 of 2

Certification Specifications and Acceptable Means of Compliance for Airborne Communications, Navigation and

Surveillance (CS-ACNS)

Issue 5

24 April 20241

1 For the date of entry into force of this Issue, please refer to ED Decision 2024/003/R at the Official Publication of EASA.

CS-ACNS Issue 5 Table of Contents

Annex to EDD 2024/003/R Page 2 of 270

TABLE OF CONTENTS

PREAMBLE ........................................................................................................................ 20

SUBPART A — GENERAL ................................................................................................... 25

CS ACNS.A.GEN.001 Applicability ............................................................................................................... 25

GM1 ACNS.A.GEN.001 Applicability ................................................................................................................. 25

CS ACNS.A.GEN.005 Definitions .................................................................................................................. 25

CS ACNS.A.GEN.010 Instructions for continued airworthiness .................................................................... 31

AMC1 ACNS.A.GEN.010 Instructions for Continued Airworthiness ................................................................. 32

CS ACNS.A.GEN.015 Aircraft documentation............................................................................................... 33

AMC1 ACNS.A.GEN.015(a) Aircraft documentation ......................................................................................... 33

CS ACNS.A.GEN.020 Deviation from equipment standards .......................................................................... 33

SUBPART B — COMMUNICATIONS (COM) ........................................................................ 34

Section 1 — Voice Channel Spacing (VCS) ................................................................................................... 34

General ............................................................................................................................................................. 34

CS ACNS.B.VCS.001 Applicability ................................................................................................................. 34

GM1 ACNS.B.VCS.001 Applicability ......................................................................................................... 34

System functional requirements ...................................................................................................................... 34

CS ACNS.B.VCS.010 Voice Communication System .................................................................................... 34

AMC1 ACNS.B.VCS.010 Voice Communication Systems .......................................................................... 34

System performance requirements ................................................................................................................. 35

CS ACNS.B.VCS.020 Performance requirements .......................................................................................... 35

CS ACNS.B.VCS.025 Integrity ....................................................................................................................... 35

CS ACNS.B.VCS.030 Continuity .................................................................................................................... 35

AMC1 ACNS.B.VCS.030 Continuity .......................................................................................................... 35

GM1 ACNS.B.VCS.030 Continuity ............................................................................................................ 35

Installation requirements ................................................................................................................................. 36

CS ACNS.B.VCS.040 Flight Deck Interface ................................................................................................... 36

AMC1 ACNS.B.VCS.040 Flight Deck Interface .......................................................................................... 36

Section 2 — Data Link Services (DLS) .......................................................................................................... 37

General ............................................................................................................................................................. 37

CS ACNS.B.DLS.001 Applicability ................................................................................................................. 37

GM1 ACNS.B.DLS.001 Applicability ......................................................................................................... 37

GM2 ACNS.B.DLS.001 Applicability ......................................................................................................... 37

CS ACNS.B.DLS.005 Installation Requirements ............................................................................................ 37

CS-ACNS Issue 5 Table of Contents

Annex to EDD 2024/003/R Page 3 of 270

AMC1 ACNS.B.DLS.005 Installation Requirements (VDL Mode 2 Sub-Network) ..................................... 38

GM1 ACNS.B.DLS.005 Data Link System Installation ............................................................................... 38

Flight deck control and indication capabilities ................................................................................................. 38

CS ACNS.B.DLS.010 Flight Deck Interface .................................................................................................... 38

AMC1 ACNS.B.DLS.010 Flight Deck Interface .......................................................................................... 39

CS ACNS.B.DLS.015 Dual Data Link Capabilities (Dual stack) ....................................................................... 40

AMC1.ACNS.B.DLS.015 Dual Data Link Capabilities (Dual stack) ............................................................. 40

ATN B1 data link and ADS-C EPP downlink capability ...................................................................................... 42

CS ACNS.B.DLS.020 Data Link Capabilities ................................................................................................... 42

AMC1 ACNS.B.DLS.020 Data Link Capabilities ......................................................................................... 42

GM1 ACNS.B.DLS.020 Data Link Capabilities ........................................................................................... 42

GM2 ACNS.B.DLS.020 Data Link Capabilities — Testing .......................................................................... 43

CS ACNS.B.DLS.025 Protection mechanism ................................................................................................. 43

AMC1 ACNS.B.DLS.025 Protection mechanism ....................................................................................... 43

System performance requirements ................................................................................................................. 44

CS ACNS.B.DLS.030 Integrity ........................................................................................................................ 44

CS ACNS.B.DLS.035 Data Link System Continuity ........................................................................................ 44

AMC1 ACNS.B.DLS.035 Data Link System Continuity .............................................................................. 44

GM1 ACNS.B.DLS.035 Data Link System Continuity ................................................................................ 44

Time .................................................................................................................................................................. 44

CS ACNS.B.DLS.040 Universal Time Coordinated (UTC) ............................................................................... 44

AMC1 ACNS.B.DLS.040 Universal Time Coordinated (UTC) ..................................................................... 44

Data Link Initiation Capability (DLIC) service messages ................................................................................... 45

CS ACNS.B.DLS.050 DLIC Uplink Messages .................................................................................................. 45

AMC1 ACNS.B.DLS.050 DLIC Uplink Messages ........................................................................................ 45

CS ACNS.B.DLS.055 DLIC Downlink Messages .............................................................................................. 45

AMC1 ACNS.B.DLS.055 DLIC Downlink Messages ................................................................................... 45

CS ACNS.B.DLS.060 DLIC initiation when in ‘CPDLC inhibited’ state (uplink) .............................................. 46

CPDLC Messages ............................................................................................................................................... 46

CS ACNS.B.DLS.070 CPDLC Uplink Messages ............................................................................................... 46

AMC1 ACNS.B.DLS.070 CPDLC Uplink Messages ..................................................................................... 47

GM1 ACNS.B.DLS.070 Uplink Messages .................................................................................................. 48

GM2 ACNS.B.DLS.070 Uplink Messages .................................................................................................. 49

CS ACNS.B.DLS.075 CPDLC Downlink Messages .......................................................................................... 49

AMC1 ACNS.B.DLS.075 Downlink Messages ........................................................................................... 50

GM1 ACNS.B.DLS.075 Downlink Messages ............................................................................................. 50

GM2 ACNS.B.DLS.075 Downlink Messages ............................................................................................. 51

CS-ACNS Issue 5 Table of Contents

Annex to EDD 2024/003/R Page 4 of 270

GM3 ACNS.B.DLS.075 Optional ACL Downlink Messages ........................................................................ 51

ADS-C EPP Data ................................................................................................................................................ 51

CS ACNS.B.DLS.077 ADS-C EPP Data ............................................................................................................ 51

AMC1 ACNS.B.DLS.077 ADS-C EPP Data .................................................................................................. 52

Data Link Services and ADS-C EPP downlink requirements ............................................................................. 52

CS ACNS.B.DLS.080 Data Link Initiation Capability (DLIC) Service ............................................................... 52

AMC1 ACNS.B.DLS.080 Data Link Initiation Capability (DLIC) Service ..................................................... 52

GM1 ACNS.B.DLS.080 Data Link Initiation Capability (DLIC) Service ....................................................... 52

CS ACNS.B.DLS.085 ATC Communications Management (ACM) Service ..................................................... 53

AMC1 ACNS.B.DLS.085 ATC Communications Management (ACM) Service ........................................... 53

GM1 ACNS.B.DLS.085 ATC Communications Management (ACM) Service ............................................. 53

CS ACNS.B.DLS.090 ACL Service Safety Requirements................................................................................. 53

AMC1 ACNS.B.DLS.090 ATC Clearances and Information (ACL) Service .................................................. 53

GM1 ACNS.B.DLS.090 ATC Clearances and Information (ACL) Service .................................................... 54

CS ACNS.B.DLS.095 ATC Microphone Check (AMC) Service ........................................................................ 54

CS ACNS.B.DLS.097 ADS-C EPP Safety and Performance Requirements ..................................................... 54

AMC1 ACNS.B.DLS.097 ADS-C EPP Safety and Performance Requirements ........................................... 54

Interoperability Requirements ......................................................................................................................... 54

CS ACNS.B.DLS.100 Network Layer Requirements ...................................................................................... 54

AMC1 ACNS.B.DLS.100 Network Layer Requirements ............................................................................ 55

GM1 ACNS.B.DLS.100 Network Layer Requirements .............................................................................. 55

CS ACNS.B.DLS.105 Transport Layer Protocol Requirements ...................................................................... 55

AMC1 ACNS.B.DLS.105 Transport Layer Protocol Requirements ............................................................ 55

GM1 ACNS.B.DLS.105 Transport Layer Protocol Requirements .............................................................. 56

CS ACNS.B.DLS.110 Session Layer Requirements ........................................................................................ 56

AMC1 ACNS.B.DLS.110 Session Layer Requirements .............................................................................. 56

CS ACNS.B.DLS.115 Presentation Layer Requirements ................................................................................ 57

AMC1 ACNS.B.DLS.115 Presentation Layer Requirements ..................................................................... 57

CS ACNS.B.DLS.120 Application Layer Requirements .................................................................................. 58

AMC1 ACNS.B.DLS.120 Application Layer Requirements ........................................................................ 58

GM1 ACNS.B.DLS.120 Application Layer Requirements .......................................................................... 58

CS ACNS.B.DLS.125 Database ...................................................................................................................... 58

GM1 ACNS.B.DLS.125 Database .............................................................................................................. 58

Appendices ....................................................................................................................................................... 58

Appendix A — Background information on voice communication systems ................................................ 58

SUBPART C — NAVIGATION (NAV) ................................................................................... 60

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN) ............................................................................ 60

CS-ACNS Issue 5 Table of Contents

Annex to EDD 2024/003/R Page 5 of 270

Subsection 1 – Applicability – General ............................................................................................................. 60

CS ACNS.C.PBN.101 Applicability ................................................................................................................. 60

AMC1 ACNS.C.PBN.101 Applicability ....................................................................................................... 61

GM1 ACNS.C.PBN.101 Applicability ......................................................................................................... 61

GM2 ACNS.C.PBN.101 Applicability ......................................................................................................... 63

Subsection 2 – Generic specifications for performance-based lateral navigation ........................................... 64

APPLICABILITY .............................................................................................................................................. 64

CS ACNS.C.PBN.201 Applicability ............................................................................................................. 64

SYSTEM QUALIFICATION CRITERIA .............................................................................................................. 64

CS ACNS.C.PBN.205 RNP system approval .............................................................................................. 64

AMC1 ACNS.C.PBN.205 RNP system approval .................................................................................... 64

AMC2 ACNS.C.PBN.205 RNP system approval .................................................................................... 65

AMC3 ACNS.C.PBN.205 RNP system approval .................................................................................... 65

GM1 ACNS.C.PBN.205 RNP system approval ...................................................................................... 65

GM2 ACNS.C.PBN.205 RNP system approval ...................................................................................... 65

GM3 ACNS.C.PBN.205 RNP system approval ...................................................................................... 66

CS ACNS.C.PBN.210 Position source ........................................................................................................ 66

AMC1 ACNS.C.PBN.210 Position source ............................................................................................. 66

FUNCTIONAL CRITERIA ................................................................................................................................. 66

RNP system .............................................................................................................................................. 66

CS ACNS.C.PBN.215 Position estimation ............................................................................................. 66

AMC1 ACNS.C.PBN.215 Position estimation ................................................................................... 67

GM1 ACNS.C.PBN.215 Position estimation..................................................................................... 67

CS ACNS.C.PBN.220 Navigation source selection and reversion ......................................................... 67

AMC1 ACNS.C.PBN.220 Navigation source selection and reversion .............................................. 67

CS ACNS.C.PBN.225 Reasonableness check of distance-measuring equipment (DME) ...................... 67

AMC1 ACNS.C.PBN.225 Reasonableness check of distance-measuring equipment (DME) ........... 67

CS ACNS.C.PBN.230 Flight plan management ..................................................................................... 68

AMC1 ACNS.C.PBN.230 Flight plan management ........................................................................... 68

CS ACNS.C.PBN.235 Automatic leg sequencing .................................................................................. 68

AMC1 ACNS.C.PBN.235 Automatic leg sequencing ........................................................................ 68

CS ACNS.C.PBN.240 Route/procedure extraction and loading ........................................................... 68

AMC1 ACNS.C.PBN.240 Route/procedure extraction and loading ................................................. 69

CS ACNS.C.PBN.245 Path definition and leg transition ....................................................................... 69

AMC1 ACNS.C.PBN.245 Path definition and leg transition ............................................................. 69

GM1 ACNS.C.PBN.245 Path definition and leg transition ............................................................... 70

CS ACNS.C.PBN.250 ‘Direct-to’ function ............................................................................................. 70

CS-ACNS Issue 5 Table of Contents

Annex to EDD 2024/003/R Page 6 of 270

AMC1 ACNS.C.PBN.250 ‘Direct-to’ function ................................................................................... 70

CS ACNS.C.PBN.255 Magnetic variation .............................................................................................. 70

AMC1 ACNS.C.PBN.255 Magnetic variation ................................................................................... 70

CS ACNS.C.PBN.260 RNAV holding ...................................................................................................... 71

AMC1 ACNS.C.PBN.260 RNAV holding ............................................................................................ 71

GM1 ACNS.C.PBN.260 RNAV holding ............................................................................................. 71

CS ACNS.C.PBN.265 User-defined routes and fixes............................................................................. 71

AMC1 ACNS.C.PBN.265 User-defined routes and fixes .................................................................. 71

GM1 ACNS.C.PBN.265 User-defined routes and fixes .................................................................... 72

CS ACNS.C.PBN.270 Navigation accuracy ............................................................................................ 72

AMC1 ACNS.C.PBN.270 Navigation accuracy ................................................................................. 72

Display of navigation data ....................................................................................................................... 72

CS ACNS.C.PBN.275 Display and entry of navigation data — resolution ............................................ 72

AMC1 ACNS.C.PBN.275 Display and entry of navigation data — resolution .................................. 72

CS ACNS.C.PBN.280 Deviation display ................................................................................................ 73

AMC1 ACNS.C.PBN.280 Deviation display ...................................................................................... 73

AMC2 ACNS.C.PBN.280 Deviation display ...................................................................................... 73

AMC3 ACNS.C.PBN.280 Deviation display ...................................................................................... 73

CS ACNS.C.PBN.285 Display of active waypoint .................................................................................. 73

AMC1 ACNS.C.PBN.285 Display of active waypoint ........................................................................ 74

AMC2 ACNS.C.PBN.285 Display of active waypoint ........................................................................ 74

CS ACNS.C.PBN.290 Display of ground speed ..................................................................................... 74

AMC1 ACNS.C.PBN.290 Display of ground speed ........................................................................... 74

CS ACNS.C.PBN.2105 Display of speed constraints ............................................................................. 74

AMC1 ACNS.C.PBN.2105 Display of speed constraints ................................................................... 74

CS ACNS.C.PBN.2110 Display of navigation aid frequencies and/or identifiers .................................. 75

Navigation database ................................................................................................................................ 75

CS ACNS.C.PBN.2115 Use of navigation database .............................................................................. 75

AMC1 ACNS.C.PBN.2115 Use of navigation database .................................................................... 75

GM1 ACNS.C.PBN.2115 Use of navigation database ...................................................................... 75

CS ACNS.C.PBN.2120 Data quality requirements (DQRs) .................................................................... 75

AMC1 ACNS.C.PBN.2120 Data quality requirements (DQRs) ......................................................... 75

CS ACNS.C.PBN.2125 Extraction and display of navigation data ........................................................ 76

AMC1 ACNS.C.PBN.2125 Extraction and display of navigation data .............................................. 76

GM1 ACNS.C.PBN.2125 Extraction and display of navigation data ................................................ 76

Monitoring and alerting .......................................................................................................................... 76

CS ACNS.C.PBN.2130 Alerting associated with degradation of navigation ......................................... 76

CS-ACNS Issue 5 Table of Contents

Annex to EDD 2024/003/R Page 7 of 270

AMC1 ACNS.C.PBN.2130 Alerting associated with degradation of navigation ............................... 77

CS ACNS.C.PBN.2135 Navigation accuracy alerting ............................................................................ 77

AMC1 ACNS.C.PBN.2135 Navigation accuracy alerting .................................................................. 77

PERFORMANCE CRITERIA ............................................................................................................................. 77

Lateral performance ................................................................................................................................ 77

CS ACNS.C.PBN.2140 Lateral navigation accuracy .............................................................................. 77

AMC1 ACNS.C.PBN.2140 Lateral navigation accuracy .................................................................... 78

CS ACNS.C.PBN.2145 RNP system design — integrity ......................................................................... 78

AMC1 ACNS.C.PBN.2145 RNP system design — integrity .............................................................. 78

CS ACNS.C.PBN.2150 RNP system design — continuity ...................................................................... 78

AMC1 ACNS.C.PBN.2150 RNP system design — continuity ............................................................ 78

Subsection 3 – Supplementary specifications for lateral navigation in final approach ................................... 78

APPLICABILITY .............................................................................................................................................. 78

CS ACNS.C.PBN.301 Applicability ............................................................................................................. 78

GM1 ACNS.C.PBN.301 Applicability .................................................................................................... 79

SUPPLEMENTARY FUNCTIONAL CRITERIA ................................................................................................... 79

RNP system .............................................................................................................................................. 79

CS ACNS.C.PBN.305 RNP system approval .......................................................................................... 79

AMC 1 ACNS.C.PBN.305 RNP system approval ............................................................................... 79

CS ACNS.C.PBN.310 Final approach intercept ..................................................................................... 79

AMC1 ACNS.C.PBN.310 Final approach intercept .......................................................................... 79

GM1 ACNS.C.PBN.310 Final approach intercept ............................................................................ 79

Display of navigation data ....................................................................................................................... 80

CS ACNS.C.PBN.320 Approach mode indication ................................................................................. 80

GM1 ACNS.C.PBN.320 Approach mode indication ......................................................................... 80

CS ACNS.C.PBN.325 Lateral deviation display .................................................................................... 80

AMC1 ACNS.C.PBN.325 Lateral deviation display ........................................................................... 80

CS ACNS.C.PBN.330 Non-numeric lateral deviation display scaling for approach .............................. 80

AMC1 ACNS.C.PBN.330 Non-numeric lateral deviation display scaling for approach .................... 80

CS ACNS.C.PBN.335 Display of distance to threshold ......................................................................... 81

Subsection 4 – Supplementary specifications for vertical navigation .............................................................. 81

APPLICABILITY .............................................................................................................................................. 81

CS ACNS.C.PBN.401 Applicability ............................................................................................................. 81

GM1 ACNS.C.PBN.401 Applicability .................................................................................................... 81

SUPPLEMENTARY FUNCTIONAL CRITERIA ................................................................................................... 81

RNP system .............................................................................................................................................. 81

CS ACNS.C.PBN.405 Vertical path ....................................................................................................... 81

CS-ACNS Issue 5 Table of Contents

Annex to EDD 2024/003/R Page 8 of 270

CS ACNS.C.PBN.410 Altitude constraints ............................................................................................ 82

AMC1 ACNS.C.PBN.410 Altitude constraints .................................................................................. 82

CS ACNS.C.PBN.420 Pressure settings ................................................................................................. 82

GM1 ACNS.C.PBN.420 Pressure settings ........................................................................................ 82

Subsection 5 – Supplementary specifications for vertical navigation in final approach .................................. 82

APPLICABILITY .............................................................................................................................................. 82

CS ACNS.C.PBN.501 Applicability ............................................................................................................. 82

GM1 ACNS.C.PBN.501 Applicability .................................................................................................... 83

SUPPLEMENTARY FUNCTIONAL CRITERIA ................................................................................................... 83

RNP system .............................................................................................................................................. 83

CS ACNS.C.PBN.505 Vertical approach path ....................................................................................... 83

AMC 1 ACNS.C.PBN.505 Vertical approach path ............................................................................ 83

CS ACNS.C.PBN.515 Pressure settings ................................................................................................. 83

GM1 ACNS.C.PBN.515 Pressure settings ........................................................................................ 83

CS ACNS.C.PBN.520 Glide path intercept ............................................................................................ 83

AMC1 ACNS.C.PBN.520 Glide path intercept ................................................................................. 84

CS ACNS.C.PBN.525 Temperature compensation ............................................................................... 84

AMC1 ACNS.C.PBN.525 Temperature compensation ..................................................................... 84

Display of navigation data ....................................................................................................................... 84

CS ACNS.C.PBN.530 Vertical deviation display .................................................................................... 84

AMC1 ACNS.C.PBN.530 Vertical deviation display ......................................................................... 84

AMC2 ACNS.C.PBN.530 Vertical deviation display ......................................................................... 85

CS ACNS.C.PBN.535 Resolution and full-scale deflection of the vertical deviation display ................ 85

AMC1 ACNS.C.PBN.535 Resolution and full-scale deflection of the vertical deviation display ...... 85

GM1 ACNS.C.PBN.535 Resolution and full-scale deflection of the vertical deviation display ........ 86

CS ACNS.C.PBN.540 Barometric altitude ............................................................................................. 86

CS ACNS.C.PBN.545 Active approach mode display ............................................................................ 86

Monitoring and alerting .......................................................................................................................... 86

CS ACNS.C.PBN.550 Glide path alerting .............................................................................................. 86

AMC1 ACNS.C.PBN.550 Glide path alerting .................................................................................... 86

SUPPLEMENTARY PERFORMANCE CRITERIA ............................................................................................... 87

Vertical performance ............................................................................................................................... 87

CS ACNS.C.PBN.555 Vertical accuracy when using barometric VNAV ................................................ 87

AMC1 ACNS.C.PBN.555 Vertical accuracy when using barometric VNAV ...................................... 87

CS ACNS.C.PBN.560 Vertical accuracy when using SBAS/GNSS geometric altitude sources .............. 89

AMC1 ACNS.C.PBN.560 Vertical accuracy when using SBAS/GNSS geometric altitude sources .... 89

GM1 ACNS.C.PBN.560 Vertical accuracy when using SBAS/GNSS geometric altitude sources ...... 89

CS-ACNS Issue 5 Table of Contents

Annex to EDD 2024/003/R Page 9 of 270

CS ACNS.C.PBN.565 Transitions .......................................................................................................... 90

AMC 1 ACNS.C.PBN.565 Transitions ............................................................................................... 90

CS ACNS.C.PBN.570 Advisory VNAV .................................................................................................... 90

AMC1 ACNS.C.PBN.570 Advisory VNAV .......................................................................................... 90

GM1 ACNS.C.PBN.570 Advisory VNAV ............................................................................................ 91

CS ACNS.C.PBN.575 RNP system design — integrity in final approach ............................................... 91

AMC1 ACNS.C.PBN.575 RNP system design — integrity in final approach .................................... 91

CS ACNS.C.PBN.580 RNP system design — continuity ........................................................................ 91

AMC1 ACNS.C.PBN.580 RNP system design — continuity .............................................................. 91

Subsection 6 – Supplementary specifications for RNP authorisation required (RNP AR) ................................ 92

APPLICABILITY .............................................................................................................................................. 92

CS ACNS.C.PBN.601 Applicability ............................................................................................................. 92

AMC1 ACNS.C.PBN.601 Applicability .................................................................................................. 92

GM1 ACNS.C.PBN.601 Applicability .................................................................................................... 92

SUPPLEMENTARY SYSTEM QUALIFICATION ................................................................................................. 93

CS ACNS.C.PBN.605 System performance demonstration ...................................................................... 93

AMC1 ACNS.C.PBN.605 System performance demonstration ............................................................ 93

GM1 ACNS.C.PBN.605 System performance demonstration .............................................................. 95

CS ACNS.C.PBN.610 Source of horizontal position .................................................................................. 95

AMC1 ACNS.C.PBN.610 Source of horizontal position ........................................................................ 95

GM1 ACNS.C.PBN.610 Source of horizontal position .......................................................................... 95

SUPPLEMENTARY FUNCTIONAL CRITERIA ................................................................................................... 96

RNP system .............................................................................................................................................. 96

CS ACNS.C.PBN.615 Autopilot/Flight director ..................................................................................... 96

CS ACNS.C.PBN.620 Reversion ............................................................................................................ 96

GM1 ACNS.C.PBN.620 Reversion .................................................................................................... 96

CS ACNS.C.PBN.625 Go-around and missed approach ....................................................................... 96

GM1 ACNS.C.PBN.625 Go-around and missed approach ............................................................... 96

CS ACNS.C.PBN.630 Radius to fix (RF) leg transition ........................................................................... 96

AMC1 ACNS.C.PBN.630 Radius to fix (RF) leg transition ................................................................. 97

CS ACNS.C.PBN.635 Navigation accuracy for RNP AR operations ....................................................... 97

AMC1 ACNS.C.PBN.635 Navigation accuracy for RNP AR operations ............................................. 97

CS ACNS.C.PBN.640 RNP AR departures – Functional Requirements ................................................. 97

AMC1 ACNS.C.PBN.640 RNP AR departures ................................................................................... 98

GM1 ACNS.C.PBN.640 RNP AR departures ..................................................................................... 98

CS ACNS.C.PBN.645 RNP AR departures – Take off performance Data .............................................. 98

Display of navigation data ....................................................................................................................... 98

CS-ACNS Issue 5 Table of Contents

Annex to EDD 2024/003/R Page 10 of 270

CS ACNS.C.PBN.650 Display of aircraft track ....................................................................................... 98

CS ACNS.C.PBN.655 Lateral deviation display ..................................................................................... 98

AMC1 ACNS.C.PBN.655 Lateral deviation display ........................................................................... 98

Navigation database ................................................................................................................................ 99

CS ACNS.C.PBN.660 Use of a navigation database .............................................................................. 99

AMC1 ACNS.C.PBN.660 Use of a navigation database ................................................................... 99

Vertical performance ............................................................................................................................... 99

CS ACNS.C.PBN.670 Vertical accuracy ................................................................................................. 99

AMC1 ACNS.C.PBN.670 Vertical accuracy ...................................................................................... 99

AMC2 ACNS.C.PBN.670 Vertical accuracy .................................................................................... 100

SUPPLEMENTARY PERFORMANCE CRITERIA ............................................................................................. 100

CS ACNS.C.PBN.675 RNP system design – RNP AR integrity .................................................................. 100

AMC1 ACNS.C.PBN.675 RNP system design — RNP AR integrity ...................................................... 100

GM1 ACNS.C.PBN.675 RNP system design – RNP AR integrity ......................................................... 100

CS ACNS.C.PBN.680 RNP system design – RNP AR continuity ............................................................... 100

AMC1 ACNS.C.PBN.680 RNP system design — RNP AR continuity ................................................... 101

GM1 ACNS.C.PBN.680 RNP system design – RNP AR continuity ....................................................... 101

Subsection 7 – Supplementary specifications for applications for advanced RNP (A-RNP) ........................... 101

APPLICABILITY ............................................................................................................................................ 101

CS ACNS.C.PBN.701 Applicability ........................................................................................................... 101

SUPPLEMENTARY FUNCTIONAL CRITERIA ................................................................................................. 101

RNP system ............................................................................................................................................ 101

CS ACNS.C.PBN.705 Radius to Fix ...................................................................................................... 101

CS ACNS.C.PBN.710 Parallel offset .................................................................................................... 101

CS ACNS.C.PBN.715 RNP scalability................................................................................................... 101

AMC1 ACNS.C.PBN.715 RNP scalability ........................................................................................ 102

Display of navigation data ..................................................................................................................... 102

CS ACNS.C.PBN.725 Display of aircraft track ..................................................................................... 102

Subsection 8 – Supplementary specifications supporting radius to fix (RF) .................................................. 102

APPLICABILITY ............................................................................................................................................ 102

CS ACNS.C.PBN.801 Applicability ........................................................................................................... 102

SUPPLEMENTARY FUNCTIONAL CRITERIA ................................................................................................. 102

RNP system ............................................................................................................................................ 102

CS ACNS.C.PBN.805 RF functional requirements .............................................................................. 102

AMC1 ACNS.C.PBN.805 RF functional requirements .................................................................... 103

GM1 ACNS.C.PBN.805 RF functional requirements ...................................................................... 103

CS ACNS.C.PBN.810 RNP failure ........................................................................................................ 103

CS-ACNS Issue 5 Table of Contents

Annex to EDD 2024/003/R Page 11 of 270

CS ACNS.C.PBN.815 Autopilot/Flight director ................................................................................... 103

AMC1 ACNS.C.PBN.815 Autopilot/Flight director ........................................................................ 104

Display of navigation data ..................................................................................................................... 104

CS ACNS.C.PBN.820 Display of computed path ................................................................................. 104

Subsection 9 – Supplementary specifications supporting fixed radius transition (FRT) ................................ 104

APPLICABILITY ............................................................................................................................................ 104

CS ACNS.C.PBN.901 Applicability ........................................................................................................... 104

SUPPLEMENTARY FUNCTIONAL CRITERIA ................................................................................................. 104

RNP system ............................................................................................................................................ 104

CS ACNS.C.PBN.905 Fixed radius transition (FRT) requirements ...................................................... 104

AMC1 ACNS.C.PBN.905 Fixed radius transition (FRT) requirements ............................................ 104

GM1 ACNS.C.PBN.905 Fixed radius transition (FRT) requirements .............................................. 105

Display of navigation data ..................................................................................................................... 105

CS ACNS.C.PBN.910 Display of the computed path .......................................................................... 105

Subsection 10 – Supplementary specifications supporting parallel offset .................................................... 105

APPLICABILITY ............................................................................................................................................ 105

CS ACNS.C.PBN.1001 Applicability ......................................................................................................... 105

SUPPLEMENTARY FUNCTIONAL CRITERIA ................................................................................................. 105

RNP system ............................................................................................................................................ 105

CS ACNS.C.PBN.1005 Parallel offset capabilities ............................................................................... 105

AMC1 ACNS.C.PBN.1005 Parallel offset capabilities ..................................................................... 106

Display of navigation data ..................................................................................................................... 106

CS ACNS.C.PBN.1010 Indication of parallel offset status .................................................................. 106

Appendix A — Guidance on classification of Failure Conditions. ................................................................107

Appendix B — INS/IRU standard performance and functionality ................................................................107

Appendix C — Installation and testing guidance ........................................................................................108

Appendix D — RF leg demonstration templates .........................................................................................115

SUBPART D — SURVEILLANCE (SUR) ............................................................................... 130

Section 1 – Mode A/C only surveillance .....................................................................................................130

General ........................................................................................................................................................... 130

CS ACNS.D.AC.001 Applicability ................................................................................................................. 130

GM1 ACNS.D.AC.001 Applicability ......................................................................................................... 130

System Functional Requirements ................................................................................................................... 130

CS ACNS.D.AC.010 Transponder characteristics ........................................................................................ 130

AMC1 ACNS.D.AC.010 Transponder characteristics .............................................................................. 130

CS ACNS.D.AC.015 Data transmission ........................................................................................................ 131

AMC1 ACNS.D.AC.015 Data transmission .............................................................................................. 132

CS-ACNS Issue 5 Table of Contents

Annex to EDD 2024/003/R Page 12 of 270

CS ACNS.D.AC.020 Altitude source ............................................................................................................ 132

AMC1 ACNS.D.AC.020 Altitude source .................................................................................................. 133

CS ACNS.D.AC.025 Flight deck interface .................................................................................................... 133

AMC1 ACNS.D.AC.025 Flight deck interface .......................................................................................... 133

System Performance Requirements ............................................................................................................... 133

CS ACNS.D.AC.030 Integrity ....................................................................................................................... 133

CS ACNS.D.AC.035 Continuity .................................................................................................................... 134

Installation Requirements .............................................................................................................................. 134

CS ACNS.D.AC.040 Dual/multiple transponder installation ....................................................................... 134

AMC1 ACNS.D.AC.040 Dual/multiple transponder installation ............................................................. 134

CS ACNS.D.AC.045 Antenna installation .................................................................................................... 134

AMC1 ACNS.D.AC.045 Antenna Installation .......................................................................................... 134

Section 2 – Mode S elementary surveillance ..............................................................................................135

General ........................................................................................................................................................... 135

CS ACNS.D.ELS.001 Applicability ................................................................................................................ 135

AMC1 ACNS.D.ELS.001 Applicability ...................................................................................................... 135

System Functional Requirements ................................................................................................................... 135

CS ACNS.D.ELS.010 Transponder characteristics ....................................................................................... 135

AMC1 ACNS.D.ELS.010 Transponder characteristics ............................................................................. 135

CS ACNS.D.ELS.015 Data transmission ....................................................................................................... 136

AMC1 ACNS.D.ELS.015 Data transmission ............................................................................................. 137

CS ACNS.D.ELS.020 On-the-ground status determination ......................................................................... 139

AMC1 ACNS.D.ELS.020 On-the-ground status determination ............................................................... 139

CS ACNS.D.ELS.025 Altitude source ........................................................................................................... 139

AMC1 ACNS.D.ELS.025 Altitude source ................................................................................................. 140

CS ACNS.D.ELS.030 Flight deck interface ................................................................................................... 141

AMC1 ACNS.D.ELS.030 Flight deck interface ......................................................................................... 141

System Performance Requirements ............................................................................................................... 141

CS ACNS.D.ELS.040 Integrity ...................................................................................................................... 141

CS ACNS.D.ELS.045 Continuity ................................................................................................................... 141

AMC1 ACNS.D.ELS.045 Continuity ......................................................................................................... 142

Installation requirements ............................................................................................................................... 142

CS ACNS.D.ELS.050 Dual/multiple transponder installation ...................................................................... 142

AMC1 ACNS.D.ELS.050 Dual/multiple transponder installation ............................................................ 142

CS ACNS.D.ELS.055 ICAO 24-bit Aircraft address ....................................................................................... 142

CS ACNS.D.ELS.060 Antenna installation ................................................................................................... 142

AMC1 ACNS.D.ELS.060 Antenna Installation ......................................................................................... 142

CS-ACNS Issue 5 Table of Contents

Annex to EDD 2024/003/R Page 13 of 270

CS ACNS.D.ELS.065 Antenna diversity ....................................................................................................... 143

AMC1 ACNS.D.ELS.065 Antenna Diversity ............................................................................................. 143

Section 3 – Mode S Enhanced Surveillance ................................................................................................144

General ........................................................................................................................................................... 144

CS ACNS.D.EHS.001 Applicability ............................................................................................................... 144

AMC1 ACNS.D.EHS.001 Applicability ..................................................................................................... 144

System Functional Requirements ................................................................................................................... 144

CS ACNS.D.EHS.010 Transponder characteristics ...................................................................................... 144

AMC1 ACNS.D.EHS.010 Transponder characteristics ............................................................................ 144

CS ACNS.D.EHS.015 Data transmission ...................................................................................................... 145

AMC1 ACNS.D.EHS.015 Data transmission ............................................................................................ 145

System Performance Requirements ............................................................................................................... 148

CS ACNS.D.EHS.020 Integrity ..................................................................................................................... 148

CS ACNS.D.EHS.025 Continuity .................................................................................................................. 149

Section 4 – 1090 MHz Extended Squitter ADS-B .........................................................................................150

General ........................................................................................................................................................... 150

CS ACNS.D.ADSB.001 Applicability ............................................................................................................. 150

GM1 ACNS.D.ADSB.001 Applicability .................................................................................................... 150

System Functional Requirements ................................................................................................................... 150

CS ACNS.D.ADSB.010 ADS-B Out system approval .................................................................................... 150

AMC1 ACNS.D.ADSB.010 ADS-B Out system approval .......................................................................... 150

ADS-B Out Data .............................................................................................................................................. 151

CS ACNS.D.ADSB.020 ADS-B Out Data Parameters .................................................................................... 151

AMC1 ACNS.D.ADSB.020(a-b) ADS-B Out data parameters .................................................................. 152

CS ACNS.D.ADSB.025 Provision of data ..................................................................................................... 152

AMC1 ACNS.D.ADSB.025(a) Provision of data — Approved sources .................................................... 152

AMC1 ACNS.D.ADSB.025(c) Provision of data – Data quality indication and associated data .............. 153

ADS-B Transmit Unit ....................................................................................................................................... 153

CS ACNS.D.ADSB.030 ADS-B Transmit Unit Approval ................................................................................ 153

AMC1 ACNS.D.ADSB.030 ADS-B Transmit unit installation ................................................................... 154

CS ACNS.D.ADSB.035 ICAO 24-bit Aircraft address .................................................................................... 154

CS ACNS.D.ADSB.040 Antenna diversity .................................................................................................... 154

AMC1 ACNS.D.ADSB.040 Antenna Diversity.......................................................................................... 154

CS ACNS.D.ADSB.045 Antenna installation ................................................................................................ 154

CS ACNS.D.ADSB.050 Transmit power ....................................................................................................... 154

CS ACNS.D.ADSB.055 Simultaneous operation of ADS-B transmit units ................................................... 155

AMC1 ACNS.D.ADSB.055 Simultaneous operation of ADS-B transmit units ......................................... 155

CS-ACNS Issue 5 Table of Contents

Annex to EDD 2024/003/R Page 14 of 270

CS ACNS.D.ADSB.060 On-the-ground status determination ...................................................................... 155

AMC1 ACNS.D.ADSB.060 On-the-ground status Determination ........................................................... 155

Horizontal Position and Velocity Data Sources .............................................................................................. 155

CS ACNS.D.ADSB.070 Horizontal Position and Velocity Data Sources ....................................................... 155

AMC1 ACNS.D.ADSB.070 Horizontal Position and Velocity Data Sources ............................................. 156

Other Data Sources ........................................................................................................................................ 158

CS ACNS.D.ADSB.080 Data Sources as defined by Mode S Elementary and Enhanced Surveillance ......... 158

AMC1 ACNS.D.ADSB.080 Data sources as defined by Mode S elementary and enhanced surveillance ............................................................................................................................................................... 158

CS ACNS.D.ADSB.085 Geometric Altitude .................................................................................................. 160

AMC1 ACNS.D.ADSB.085 Geometric Altitude ....................................................................................... 160

Flight Deck Control and Indication Capabilities .............................................................................................. 161

CS ACNS.D.ADSB.090 Flight deck interface ................................................................................................ 161

AMC1 ACNS.D.ADSB.090(a) Flight deck interface ................................................................................. 161

AMC1 ACNS.D.ADSB.090(b) Flight Deck Interface ................................................................................. 161

System Performance Requirements ............................................................................................................... 162

CS ACNS.D.ADSB.100 Integrity ................................................................................................................... 162

CS ACNS.D.ADSB.105 Continuity ................................................................................................................ 162

AMC1 ACNS.D.ADSB.105 Continuity...................................................................................................... 163

Horizontal Position and Velocity Data Refresh Rate and Latency .................................................................. 163

CS ACNS.D.ADSB.110 Horizontal position and velocity data refresh rate ................................................. 163

AMC1 ACNS.D.ADSB.110 Horizontal Position and Velocity Data Refresh ............................................. 163

CS ACNS.D.ADSB.115 Horizontal Position and Velocity Total Latency ....................................................... 163

CS ACNS.D.ADSB.120 Horizontal Position Uncompensated Latency ......................................................... 163

AMC1 ACNS.D.ADSB.115 and 120 Horizontal Position and Velocity Total and Uncompensated Latency ............................................................................................................................................................... 163

Appendices ...............................................................................................................................................166

Appendix A – Background information on Mode A/C surveillance systems .................................................. 166

Appendix B – Background information on Mode S ELS .................................................................................. 167

Appendix C – Background information on Mode S EHS ................................................................................. 171

Appendix D – Differences between CS ACNS.D.ELS and JAA TGL 13 Rev1 ..................................................... 175

Appendix E – Differences between CS ACNS.D.EHS and EASA AMC 20-13 .................................................... 176

Appendix F – Example of Flight Manual Supplement for ELS/EHS ................................................................. 176

Appendix G – Example of Flight Manual Supplement for ADS-B out ............................................................. 177

Appendix H – Guidance on 1090 MHz extended squitter ADS-B Out ............................................................ 179

Appendix I – On-the-ground status Test and Validation Guidance for Aeroplanes ....................................... 203

Appendix J – Comparison between EASA CS ACNS.D.ADSB and FAA AC 20-165A Requirements ................. 204

SUBPART E — OTHERS .................................................................................................... 206

CS-ACNS Issue 5 Table of Contents

Annex to EDD 2024/003/R Page 15 of 270

Section 1 – Terrain Awareness and Warning System (TAWS) ......................................................................206

General ........................................................................................................................................................... 206

CS ACNS.E.TAWS.001 Applicability ............................................................................................................ 206

GM1 ACNS.E.TAWS.001 Applicability .................................................................................................... 206

CS ACNS.E.TAWS.005 TAWS Equipment Approval ..................................................................................... 206

AMC1 ACNS.E.TAWS.005 TAWS equipment approval ........................................................................... 206

System functional requirements .................................................................................................................... 206

CS ACNS.E.TAWS.010 Required Functions and Interfaces ......................................................................... 206

AMC1 ACNS.E.TAWS.010 Required functions ....................................................................................... 207

AMC 2 ACNS.E.TAWS.010 Required functions ...................................................................................... 208

CS ACNS.E.TAWS.015 FLTA function requirements ................................................................................... 208

AMC1 ACNS.E.TAWS.015 FLTA function requirements ......................................................................... 209

CS ACNS.E.TAWS.020 PDA function requirements .................................................................................... 209

GM1 ACNS.E.TAWS.020 PDA function requirements ............................................................................ 209

CS ACNS.E.TAWS.025 Class A TAWS inhibition .......................................................................................... 210

AMC1 ACNS.E.TAWS.025 Class A TAWS inhibition ................................................................................ 210

CS ACNS.E.TAWS.030 Terrain information display .................................................................................... 210

AMC1 ACNS.E.TAWS.030 Terrain information display .......................................................................... 211

CS ACNS.E.TAWS.035 Aural and visual alerts ............................................................................................. 211

AMC1 ACNS.E.TAWS.035 Aural and visual alerts .................................................................................. 211

System performance requirements ............................................................................................................... 213

CS ACNS.E.TAWS.040 Integrity .................................................................................................................. 213

AMC1 ACNS.E.TAWS.040 Integrity ........................................................................................................ 213

CS ACNS.E.TAWS.045 Continuity ............................................................................................................... 214

AMC1 ACNS.E.TAWS.045 Continuity ..................................................................................................... 214

GM1 ACNS.E.TAWS.045 Continuity ....................................................................................................... 214

CS ACNS.E.TAWS.050 GPWS ...................................................................................................................... 214

CS ACNS.E.TAWS.055 Terrain and airport information .............................................................................. 214

AMC1 ACNS.E.TAWS.055 Terrain and airport information ................................................................... 214

CS ACNS.E.TAWS.060 Positioning information .......................................................................................... 215

AMC1 ACNS.E.TAWS.060 Positioning information ................................................................................ 215

Installation requirements ............................................................................................................................... 216

CS ACNS.E.TAWS.070 Failure mode ........................................................................................................... 216

CS ACNS.E.TAWS.075 Prioritisation scheme .............................................................................................. 216

AMC1 ACNS.E.TAWS.075 Prioritisation schemes .................................................................................. 216

CS ACNS.E.TAWS.080 Pop-up mode .......................................................................................................... 217

AMC1 ACNS.E.TAWS.080 Pop-up mode ................................................................................................ 218

CS-ACNS Issue 5 Table of Contents

Annex to EDD 2024/003/R Page 16 of 270

Appendices ..................................................................................................................................................... 218

Appendix A – TAWS installations testing guidance material ..................................................................... 218

Appendix B – Example of an acceptable TAWS installation ....................................................................... 220

Appendix C – Background information on terrain awareness and warning systems (TAWSs) .................. 221

Section 2 – Reduced Vertical Separation Minimum (RVSM) .......................................................................223

General ........................................................................................................................................................... 223

CS ACNS.E.RVSM.001 Applicability ............................................................................................................ 223

AMC1 ACNS.E.RVSM.001 Applicability .................................................................................................. 223

CS ACNS.E.RVSM.005 RVSM system .......................................................................................................... 223

AMC1 ACNS.E.RVSM.005 RVSM system ................................................................................................ 223

System functional requirements .................................................................................................................... 224

CS ACNS.E.RVSM.010 Required functions.................................................................................................. 224

AMC1 ACNS.E.RVSM.010 Required functions ....................................................................................... 224

System performance requirements ............................................................................................................... 224

CS ACNS.E.RVSM.020 Integrity .................................................................................................................. 224

CS ACNS.E.RVSM.025 Continuity ............................................................................................................... 224

CS ACNS.E.RVSM.030 RVSM system performance .................................................................................... 224

AMC1 ACNS.E.RVSM.030 RVSM system performance requirement ..................................................... 225

CS ACNS.E.RVSM.035 Altimetry system accuracy ...................................................................................... 225

AMC1 ACNS.E.RVSM.035 Altimetry system accuracy ........................................................................... 225

GM1 ACNS.E.RVSM.035 Altimetry System Accuracy ............................................................................. 228

Appendices ..................................................................................................................................................... 229

APPENDIX A – ALTIMETRY SYSTEM ERROR COMPONENTS ....................................................................... 229

Appendix B – Examples of methods to establish and monitor static-source errors (group aircraft only) . 236

Section 3 – Location of an Aircraft in Distress ............................................................................................239

General ........................................................................................................................................................... 239

CS ACNS.E.LAD.001 Applicability and scope .............................................................................................. 239

GM1 ACNS.E.LAD.001 Applicability and scope ...................................................................................... 239

CS ACNS.E.LAD.010 Definitions .................................................................................................................. 240

GM1 ACNS.E.LAD.010 Definitions ......................................................................................................... 242

CS ACNS.E.LAD.020 System approval ......................................................................................................... 243

AMC1 ACNS.E.LAD.020 System approval .............................................................................................. 243

AMC2 ACNS.E.LAD.020 System approval .............................................................................................. 243

AMC3 ACNS.E.LAD.020 System approval .............................................................................................. 244

Transmission .................................................................................................................................................. 244

CS ACNS.E.LAD.110 Transmission of the activation signals ....................................................................... 244

AMC1 ACNS.E.LAD.110 Transmission of the activation signals ............................................................. 244

CS-ACNS Issue 5 Table of Contents

Annex to EDD 2024/003/R Page 17 of 270

AMC2 ACNS.E.LAD.110 Transmission of the activation signals ............................................................. 244

AMC3 ACNS.E.LAD.110 Transmission of the activation signals ............................................................. 245

GM1 ACNS.E.LAD.110 Transmission of the activation signals ............................................................... 245

CS ACNS.E.LAD.120 Repeated transmission of the activation signals ....................................................... 245

AMC1 ACNS.E.LAD.120 Repeated transmission of the activation signals ............................................. 245

CS ACNS.E.LAD.130 Transmission of the deactivation signals ................................................................... 245

AMC1 ACNS.E.LAD.130 Transmission of the deactivation signals ......................................................... 246

CS ACNS.E.LAD.140 Activation signals — essential information ................................................................ 246

AMC1 ACNS.E.LAD.140 Activation signals — essential information ..................................................... 246

GM1 ACNS.E.LAD.140 Activation signals — essential information ....................................................... 246

CS ACNS.E.LAD.150 Activation signals — supplementary .......................................................................... 247

GM1 ACNS.E.LAD.150 Activation signals — supplementary ................................................................. 247

CS ACNS.E.LAD.160 Deactivation signals — essential information ............................................................ 247

CS ACNS.E.LAD.170 Transmission of a homing signal ................................................................................ 247

AMC1 ACNS.E.LAD.170 Transmission of a homing signal ...................................................................... 248

GM1 ACNS.E.LAD.170 Transmission of a homing signal ........................................................................ 248

Operation, activation and deactivation .......................................................................................................... 248

CS ACNS.E.LAD.210 Normal operation....................................................................................................... 248

AMC1 ACNS.E.LAD.210 Normal operation ............................................................................................ 249

AMC2 ACNS.E.LAD.210 Normal operation ............................................................................................ 249

GM1 ACNS.E.LAD.210 Normal operation .............................................................................................. 249

GM2 ACNS.E.LAD.210 Normal operation .............................................................................................. 249

CS ACNS.E.LAD.230 Continued operation after losing normal electrical power........................................ 249

GM1 ACNS.E.LAD.230 Continued operation after losing normal electrical power ............................... 250

GM2 ACNS.E.LAD.230 Continued operation after losing normal electrical power ............................... 250

CS ACNS.E.LAD.240 Automatic activation .................................................................................................. 250

AMC1 ACNS.E.LAD.240 Automatic activation ....................................................................................... 250

AMC2 ACNS.E.LAD.240 Automatic activation ....................................................................................... 251

GM1 ACNS.E.LAD.240 Automatic activation ......................................................................................... 251

GM2 ACNS.E.LAD.240 Automatic activation ......................................................................................... 251

CS ACNS.E.LAD.250 Manual activation ...................................................................................................... 252

AMC1 ACNS.E.LAD.250 Manual activation ............................................................................................ 252

GM1 ACNS.E.LAD.250 Manual activation .............................................................................................. 252

CS ACNS.E.LAD.260 Automatic deactivation .............................................................................................. 252

GM1 ACNS.E.LAD.260 Automatic deactivation ..................................................................................... 252

CS ACNS.E.LAD.270 Manual deactivation .................................................................................................. 252

CS ACNS.E.LAD.280 Indications to the flight crew and self-monitoring .................................................... 253

CS-ACNS Issue 5 Table of Contents

Annex to EDD 2024/003/R Page 18 of 270

AMC1 ACNS.E.LAD.280 Indications to the flight crew and self-monitoring .......................................... 253

GM1 ACNS.E.LAD.280 Indications to the flight crew and self-monitoring ............................................ 253

CS ACNS.E.LAD.290 Means to analyse automatic activation ..................................................................... 253

AMC1 ACNS.E.LAD.290 Means to analyse automatic activation ........................................................... 253

Robustness ..................................................................................................................................................... 254

CS ACNS.E.LAD.310 Environmental and crash conditions encountered during accidents ........................ 254

AMC1 ACNS.E.LAD.310 Environmental and crash conditions encountered during accidents .............. 254

AMC2 ACNS.E.LAD.310 Environmental and crash conditions encountered during accidents .............. 258

AMC3 ACNS.E.LAD.310 Environmental and crash conditions encountered during accidents .............. 258

AMC4 ACNS.E.LAD.310 Environmental and crash conditions encountered during accidents .............. 258

GM1 ACNS.E.LAD.310 Environmental and crash conditions encountered during accidents ................ 259

CS ACNS.E.LAD.320 Flight dynamics and locating the aircraft ................................................................... 259

AMC1 ACNS.E.LAD.320 Flight dynamics and locating the aircraft ......................................................... 260

AMC2 ACNS.E.LAD.320 Flight dynamics and locating the aircraft ......................................................... 260

AMC3 ACNS.E.LAD.320 Flight dynamics and locating the aircraft ......................................................... 261

GM1 ACNS.E.LAD.320 Flight dynamics and locating the aircraft .......................................................... 262

CS ACNS.E.LAD.340 Activation and transmission over water and over land ............................................. 262

AMC1 ACNS.E.LAD.340 Activation and transmission over water and over land ................................... 262

CS ACNS.E.LAD.350 Means and procedures to prevent undesirable activation ........................................ 263

AMC1 ACNS.E.LAD.350 Means and procedures to prevent undesirable activation ............................. 263

GM1 ACNS.E.LAD.350 Means and procedures to prevent undesirable activation ............................... 263

CS ACNS.E.LAD.360 Shared airborne resources and transmission means ................................................. 264

GM1 ACNS.E.LAD.360 Shared airborne resources and transmission means ........................................ 264

Accuracy ......................................................................................................................................................... 264

CS ACNS.E.LAD.410 Position accuracy for non-survivable accidents ......................................................... 264

AMC1 ACNS.E.LAD.410 Position accuracy for non-survivable accidents ............................................... 264

AMC2 ACNS.E.LAD.410 Position accuracy for non-survivable accidents ............................................... 265

GM1 ACNS.E.LAD.410 Position accuracy for non-survivable accidents................................................. 265

CS ACNS.E.LAD.420 Position accuracy for survivable accidents ................................................................ 265

AMC1 ACNS.E.LAD.420 Position accuracy for survivable accidents ...................................................... 265

Interoperability .............................................................................................................................................. 266

CS ACNS.E.LAD.520 Frequency spectrum .................................................................................................. 266

AMC1 ACNS.E.LAD.520 Frequency spectrum ........................................................................................ 266

System performance ...................................................................................................................................... 266

CS ACNS.E.LAD.610 Continuity ................................................................................................................... 266

AMC1 ACNS.E.LAD.610 Continuity ........................................................................................................ 266

GM1 ACNS.E.LAD.610 Continuity .......................................................................................................... 267

CS-ACNS Issue 5 Table of Contents

Annex to EDD 2024/003/R Page 19 of 270

CS ACNS.E.LAD.620 Integrity ...................................................................................................................... 267

AMC1 ACNS.E.LAD.620 Integrity ........................................................................................................... 267

GM1 ACNS.E.LAD.620 Integrity ............................................................................................................. 267

CS ACNS.E.LAD.650 Risk for third parties ................................................................................................... 268

AMC1 ACNS.E.LAD.650 Risk for third parties ........................................................................................ 268

Appendices ..................................................................................................................................................... 268

Appendix A — Example flight trajectory .................................................................................................... 268

CS-ACNS Issue 5 Preamble

Annex to EDD 2024/003/R Page 20 of 270

PREAMBLE

CS-ACNS Issue 5

ED Decision 2024/003/R

The following is a list of paragraphs affected by this Issue:

Subpart A

CS ACNS.A.GEN.005 Amended (NPA 2023-07)

Subpart B

Section 2 — Data Link Services (DLS) Amended (NPA 2023-07)

General

CS ACNS.B.DLS.B1.001 Amended (NPA 2023-07)

GM1 ACNS.B.DLS.B1.001 Amended (NPA 2023-07)

GM2 ACNS.B.DLS.001 Added (NPA 2023-07)

CS ACNS.B.DLS.B1.005 Amended (NPA 2023-07)

AMC1 ACNS.B.DLS.005 Created (NPA 2023-07)

GM1 ACNS.B.DLS.B1.005 Amended (NPA 2023-07)

Flight deck control and indication capabilities

CS ACNS.B.DLS.B1.010 Amended (NPA 2023-07)

AMC1 ACNS.B.DLS.B1.010 Amended (NPA 2023-07)

CS ACNS.B.DLS.B1.015 Amended (NPA 2023-07)

AMC1.ACNS.B.DLS.B1.015 Amended (NPA 2023-07)

ATN B1 data link Amended (NPA 2023-07)

CS ACNS.B.DLS.B1.020 Amended (NPA 2023-07)

AMC1 ACNS.B.DLS.B1.020 Amended (NPA 2023-07)

GM1 ACNS.B.DLS.B1.020 Amended (NPA 2023-07)

GM2 ACNS.B.DLS.B1.020 Created (NPA 2023-07)

CS ACNS.B.DLS.B1.025 Amended (NPA 2023-07)

AMC1 ACNS.B.DLS.B1.025 Amended (NPA 2023-07)

AMC2 ACNS.B.DLS.B1.025 Deleted (NPA 2023-07)

AMC3 ACNS.B.DLS.B1.025 Deleted (NPA 2023-07)

GM1 ACNS.B.DLS.B1.025 Deleted (NPA 2023-07)

GM2 ACNS.B.DLS.B1.025 Deleted (NPA 2023-07)

GM3 ACNS.B.DLS.B1.025 Deleted (NPA 2023-07)

System performance requirements

CS ACNS.B.DLS.B1.030 Amended (NPA 2023-07)

CS ACNS.B.DLS.B1.035 Amended (NPA 2023-07)

AMC1 ACNS.B.DLS.B1.035 Amended (NPA 2023-07)

GM1 ACNS.B.DLS.B1.035 Amended (NPA 2023-07)

Time

CS ACNS.B.DLS.B1.040 Amended (NPA 2023-07)

CS-ACNS Issue 5 Preamble

Annex to EDD 2024/003/R Page 21 of 270

AMC1 ACNS.B.DLS.B1.040 Amended (NPA 2023-07)

Data link initiation capability (DLIC) service messages

CS ACNS.B.DLS.B1.050 Amended (NPA 2023-07)

AMC1 ACNS.B.DLS.B1.050 Amended (NPA 2023-07)

CS ACNS.B.DLS.B1.055 Amended (NPA 2023-07)

AMC1 ACNS.B.DLS.B1.055 Amended (NPA 2023-07)

CS ACNS.B.DLS.B1.060 Amended (NPA 2023-07)

CPDLC Messages

CS ACNS.B.DLS.B1.070 Amended (NPA 2023-07)

AMC1 ACNS.B.DLS.B1.070 Amended (NPA 2023-07)

GM1 ACNS.B.DLS.B1.070 Amended (NPA 2023-07)

GM2 ACNS.B.DLS.B1.070 Amended (NPA 2023-07)

CS ACNS.B.DLS.B1.075 Amended (NPA 2023-07)

AMC1 ACNS.B.DLS.B1.075 Amended (NPA 2023-07)

GM1 ACNS.B.DLS.B1.075 Amended (NPA 2023-07)

GM2 ACNS.B.DLS.B1.075 Amended (NPA 2023-07

GM3 ACNS.B.DLS.B1.075 Amended (NPA 2023-07

ADS-C EPP Data Created (NPA 2023-07)

CS ACNS.B.DLS.077 Created (NPA 2023-07)

AMC1 ACNS.B.DLS.077 Created (NPA 2023-07)

Data link services requirements Amended (NPA 2023-07)

CS ACNS.B.DLS.B1.080 Amended (NPA 2023-07)

AMC1 ACNS.B.DLS.B1.080 Amended (NPA 2023-07)

GM1 ACNS.B.DLS.B1.080 Amended (NPA 2023-07)

CS ACNS.B.DLS.B1.085 Amended (NPA 2023-07)

AMC1 ACNS.B.DLS.B1.085 Amended (NPA 2023-07)

GM1 ACNS.B.DLS.B1.085 Amended (NPA 2023-07)

CS ACNS.B.DLS.B1.090 Amended (NPA 2023-07)

AMC1 ACNS.B.DLS.B1.090 Amended (NPA 2023-07)

GM1 ACNS.B.DLS.B1.090 Amended (NPA 2023-07)

CS ACNS.B.DLS.B1.095 Amended (NPA 2023-07)

CS ACNS.B.DLS.097 Created (NPA 2023-07)

AMC1 ACNS.B.DLS.097 Created (NPA 2023-07)

Interoperability Requirements

CS ACNS.B.DLS.B1.100 Amended (NPA 2023-07)

AMC1 ACNS.B.DLS.B1.100 Amended (NPA 2023-07)

GM1 ACNS.B.DLS.B1.100 Amended (NPA 2023-07)

CS ACNS.B.DLS.B1.105 Amended (NPA 2023-07)

AMC1 ACNS.B.DLS.B1.105 Amended (NPA 2023-07)

GM1 ACNS.B.DLS.B1.105 Amended (NPA 2023-07)

CS ACNS.B.DLS.B1.110 Amended (NPA 2023-07)

AMC1 ACNS.B.DLS.B1.110 Amended (NPA 2023-07)

CS-ACNS Issue 5 Preamble

Annex to EDD 2024/003/R Page 22 of 270

CS ACNS.B.DLS.B1.115 Amended (NPA 2023-07)

AMC1 ACNS.B.DLS.B1.115 Amended (NPA 2023-07)

CS ACNS.B.DLS.B1.120 Amended (NPA 2023-07)

AMC1 ACNS.B.DLS.B1.120 Amended (NPA 2023-07)

GM1 ACNS.B.DLS.B1.120 Amended (NPA 2023-07)

CS ACNS.B.DLS.B1.125 Amended (NPA 2023-07)

GM1 ACNS.B.DLS.125 Created (NPA 2023-07)

Appendices

Appendix A Amended (NPA 2023-07)

Appendix B Deleted (NPA 2023-07)

CS-ACNS Issue 4

ED Decision 2022/008/R

The following is a list of paragraphs affected by this Issue:

Subpart A

CS ACNS.A.GEN.001 Amended (NPA 2021-04)

CS ACNS.A.GEN.005 Amended (NPA 2021-04)

Subpart B

CS ACNS.B.VCS.001 Amended (NPA 2021-04)

GM1 ACNS.B.VCS.001 New (NPA 2021-04)

CS ACNS.B.VCS.020 Amended (NPA 2021-04)

GM1 ACNS.B.DLS.B1.001 Amended (NPA 2021-04)

AMC1 ACNS.B.DLS.B1.010 Amended (NPA 2021-04)

GM1 ACNS.B.DLS.B1.020 Amended (NPA 2021-04)

GM1 ACNS.B.DLS.B1.020 (duplicated title) Deleted (NPA 2021-04)

CS ACNS.B.DLS.B1.035 Amended (NPA 2021-04)

AMC1 ACNS.B.DLS.B1.035 New (NPA 2021-04)

GM1 ACNS.B.DLS.B1.035 New (NPA 2021-04)

CS ACNS.B.DLS.B1.060 DLIC Amended (NPA 2021-04)

CS ACNS.B.DLS.B1.070 CPDLC Amended (NPA 2021-04)

AMC1 ACNS.B.DLS.B1.070 CPDLC Amended (NPA 2021-04)

AMC2 ACNS.B.DLS.B1.070 Deleted (NPA 2021-04)

CS ACNS.B.DLS.B1.075 CPDLC Amended (NPA 2021-04)

AMC1 ACNS.B.DLS.B1.075 Amended (NPA 2021-04)

GM1 ACNS.B.DLS.B1.075 Amended (NPA 2021-04)

CS ACNS.B.DLS.B1.080 Amended (NPA 2021-04)

CS ACNS.B.DLS.B1.085 Amended (NPA 2021-04)

CS ACNS.B.DLS.B1.090 Amended (NPA 2021-04)

CS ACNS.B.DLS.B1.095 Amended (NPA 2021-04)

CS ACNS.B.DLS.B1.115 Amended (NPA 2021-04)

Appendix A Amended (NPA 2021-04)

Appendix B Amended (NPA 2021-04)

Subpart C

CS-ACNS Issue 5 Preamble

Annex to EDD 2024/003/R Page 23 of 270

CS ACNS.C.PBN.255 Amended (NPA 2021-04)

GM1 ACNS.C.PBN.501 Amended (NPA 2021-04)

AMC1 ACNS.C.PBN.535 Amended (NPA 2021-04)

AMC1 ACNS.C.PBN.555 Amended (NPA 2021-04)

CS ACNS.C.PBN.615 Amended (NPA 2021-04)

CS ACNS.C.PBN.675 Amended (NPA 2021-04)

GM1 ACNS.C.PBN.675 New (NPA 2021-04)

CS ACNS.C.PBN.680 Amended (NPA 2021-04)

GM1 ACNS.C.PBN.680 New (NPA 2021-04)

Subpart D

CS ACNS.D.AC.001 Amended (NPA 2021-04)

GM1 ACNS.D.AC.001 New (NPA 2021-04)

CS ACNS.D.AC.040 Amended (NPA 2021-04)

AMC1 ACNS.D.AC.040 Amended (NPA 2021-04)

AMC1 ACNS.D.ELS.001 Amended (NPA 2021-04)

AMC1 ACNS.D.ELS.015 Amended (NPA 2021-04)

CS ACNS.D.ELS.025 Amended (NPA 2021-04)

AMC1 ACNS.D.ELS.025 Amended (NPA 2021-04)

CS ACNS.D.ELS.045 Amended (NPA 2021-04)

AMC1 ACNS.D.ELS.045 New (NPA 2021-04)

AMC1 ACNS.D.EHS.001 Amended (NPA 2021-04)

CS ACNS.D.EHS.015 Amended (NPA 2021-04)

GM1 ACNS.D.ADSB.001 Amended (NPA 2021-04)

CS ACNS.D.ADSB.025 Amended (NPA 2021-04)

AMC1 ACNS.D.ADSB.080 Amended (NPA 2021-04)

AMC1 ACNS.D.ADSB.090(a) Amended (NPA 2021-04)

CS ACNS.D.ADSB.105 Amended (NPA 2021-04)

AMC1 ACNS.D.ADSB.105 New (NPA 2021-04)

CS ACNS.D.ADSB.110 Amended (NPA 2021-04)

Appendix A Amended (NPA 2021-04)

Appendix B Amended (NPA 2021-04)

Appendix C Amended (NPA 2021-04)

Appendix D Amended (NPA 2021-04)

Appendix E Amended (NPA 2021-04)

Appendix H Amended (NPA 2021-04)

Subpart E

GM1 ACNS.E.TAWS.001 Amended (NPA 2021-04)

AMC1 ACNS.E.TAWS.010 Amended (NPA 2021-04)

AMC1 ACNS.E.TAWS.030 Amended (NPA 2021-04)

CS ACNS.E.TAWS.040 Amended (NPA 2021-04)

AMC1 ACNS.E.TAWS.040 New (NPA 2021-04)

CS ACNS.E.TAWS.045 Amended (NPA 2021-04)

AMC1 ACNS.E.TAWS.045 New (NPA 2021-04)

GM1 ACNS.E.TAWS.045 New (NPA 2021-04)

Appendix A Amended (NPA 2021-04)

Appendix B Amended (NPA 2021-04)

CS-ACNS Issue 5 Preamble

Annex to EDD 2024/003/R Page 24 of 270

Appendix C Amended (NPA 2021-04)

CS ACNS.E.RVSM.035 Amended (NPA 2021-04)

Appendix B Amended (NPA 2021-04)

CS-ACNS Issue 3

ED Decision 2021/008/R

The following is a list of paragraphs affected by this Issue:

Subpart E

Section 3 – Location of an aircraft in distress New (NPA 2020-03)

CS-ACNS Issue 2

ED Decision 2019/011/R

The following is a list of paragraphs affected by this Issue:

Subpart A

CS ACNS.A.GEN.001 Amended (NPA 2018-02)

CS ACNS.A.GEN.005 Amended (NPA 2018-02)

CS ACNS.A.GEN.015 New (NPA 2018-02)

AMC1 ACNS.A.GEN.015(a) New (NPA 2018-02)

CS ACNS.A.GEN.020 New (NPA 2018-02)

Subpart B

CS ACNS.B.VCS.020 Amended (NPA 2018-02)

CS ACNS.B.VCS.030 Amended (NPA 2018-02)

GM1 ACNS.B.VCS.030 New (NPA 2018-02)

Subpart C

CS ACNS.C.PBN.XXX New (NPA 2018-02)

AMC and GM ACNS.C.PBN.XXX New (NPA 2018-02)

Subpart E

AMC1 ACNS.E.TAWS.035 Amended (NPA 2018-02)

CS-ACNS Issue 5 Subpart A — General

Annex to EDD 2024/003/R Page 25 of 270

SUBPART A — GENERAL

CS ACNS.A.GEN.001 Applicability These certification specifications provide standards for the certification and approval of designs, or changes to designs of aircraft, allowing aircraft operators to comply with the applicable airspace requirements or mandatory equipage requirements in the areas of:

— Communication, Navigation and Surveillance (CNS);

— Terrain Awareness and Warning Systems (TAWS);

— Reduced Vertical Separation Minima (RVSM); and

— Location of an Aircraft in Distress (LAD / GADSS).

[Issue: CS-ACNS/2]

[Issue: CS-ACNS/4]

GM1 ACNS.A.GEN.001 Applicability A reference to compliance with the relevant section(s) of CS-ACNS in the aircraft flight manual (AFM) or other approved document may be used by operators to demonstrate compliance with the applicable airspace rules.

[Issue: CS-ACNS/4]

CS ACNS.A.GEN.005 Definitions This point contains the definitions of terms used in CS-ACNS:

Accuracy is, in the context of PBN operations, the degree of conformance between the estimated, measured or desired position and/or the velocity of a platform at a given time, and its true position or velocity.

ADS-B refers to automatic dependent surveillance - broadcast, a surveillance technique in which aircraft automatically provide, via a data link, data derived from on-board navigation and position- fixing systems. It refers to a surveillance technology where ADS-B Out equipped aircraft broadcast position, altitude, velocity, and other information in support of both air-to-ground and air-to-air surveillance applications.

ADS-B device failure refers to a condition announced to the flight crew whereby the ADS-B transmit unit is unable to transmit ADS-B messages.

ADS-B function failure refers to a condition announced to the flight crew whereby the position source(s) or interconnecting avionics fail to provide horizontal position data to the ADS-B transmit unit.

ADS-B Out system refers to the overall set of avionics that generate, transport, process, and transmit ADS-B data.

ADS-B transmit unit refers to that part of the ADS-B Out system that resides within the transponder and transmits 1090 MHz ES ADS-B data, including the data processing within that system.

ADS-C refers to automatic dependent surveillance-contract and is a means by which the terms of an ADS-C agreement will be exchanged between the ground system and the aircraft via data link.

CS-ACNS Issue 5 Subpart A — General

Annex to EDD 2024/003/R Page 26 of 270

Advisory alerts refers to the level or category of alert for conditions that require flight crew awareness and may require subsequent flight crew response.

Advisory vertical navigation (‘Advisory VNAV’) is an area navigation system function guiding the aircraft on a vertical path calculated by the area navigation system on an approach procedure that has been designed as a 2D procedure.

Aircraft Identification is an alphanumeric chain that contains information allowing operational identification of individual flights. It contains either the Aircraft Identification as registered in item 7 of the flight plan or the aircraft registration if no flight plan has been filed.

Airship is a power-driven lighter-than-air aircraft.

Alert is a generic term used to describe a flight deck indication meant to attract the attention of and identify to the flight crew a non-normal operational or aeroplane system condition. Alerts are classified at levels or categories corresponding to Warning, Caution, and Advisory. Alert indications also include non-normal range markings (for example, exceedances on instruments and gauges).

Altimetry system error (ASE) refers to the difference between the altitude indicated by the altimeter display, assuming a correct altimeter barometric setting, and the pressure altitude corresponding to the undisturbed ambient pressure.

Area navigation (RNAV) is a method of navigation which permits aircraft operation on any desired flight path within the coverage of ground or space-based navigation aids or within the limits of the capability of self-contained aids, or a combination of these.

Aircraft-based augmentation system (ABAS) is an augmentation system that augments and/or integrates the information obtained from the GNSS core constellation elements with other information available on board the aircraft.

ATN B1 refers to Aeronautical Telecommunication Network Build 1.

ATS communications management service (ACM) is a service that provides automated assistance to flight crews and air traffic controllers for conducting the transfer of ATC communications (voice and data).

ATS clearance and information service (ACL) is a service that provides flight crews and controllers with the ability to conduct operational exchanges.

ATS microphone check service (AMC) is a service that provides air traffic controllers with the capability to send an instruction to one or several data link equipped aircraft, at the same time, in order to instruct flight crew(s) to verify that his/their voice communication equipment is not blocking a given voice channel.

Aural alert is a discrete sound, tone, or verbal statement used to annunciate a condition, situation, or event.

Automatic altitude control system is any system that is designed to automatically control the aircraft to a referenced pressure altitude.

Barometric altitude rate refers to the rate of climb estimated by using the difference of pressure.

Barometric pressure setting is the barometric pressure setting used by the pilot when flying the aircraft.

Comm-B refers to a 112-bit Mode S reply containing a 56-bit MB message field containing the extracted transponder register.

Caution refers to the level or category of alert for conditions that require immediate flight crew awareness and a less urgent subsequent flight crew response than a warning alert.

CS-ACNS Issue 5 Subpart A — General

Annex to EDD 2024/003/R Page 27 of 270

Continuity of function refers, in the context of PBN operations, to the capability of the system to perform its intended function without unscheduled interruptions.

Continuity (system continuity) is the probability that a system will perform its required function without unscheduled interruption, assuming that the system is available at the initiation of the intended operation.

Controlled flight into terrain (CFIT) is an accident or incident in which an aircraft, under the full control of the pilot, is flown into terrain, obstacles, or water.

Controller–pilot data link communications (CPDLC) is a data link application that provides a means of communication between the controller and the pilot.

Data link is a communication technology where ‘Data Link’ equipped aircraft communicate with ‘Data Link’ capable ground units to exchange digital information (bi-directional exchange).

Data link communications initiation capability (DLIC) is a service that enables the exchange of the necessary information for the establishment of data link communications between the ground and aircraft data link systems.

Data quality indicator refers to integrity and/or accuracy quality metrics that are associated with some of the ADS-B Out surveillance data, in particular with the horizontal position.

Defined path is the output of the path definition function of the RNP System.

Desired path is the path that the flight crew and air traffic control can expect the aircraft to fly, given a particular route leg or transition.

Distance-measuring equipment (DME) refers to a ground–airborne positioning system based on interrogations from an airborne interrogator and replies from a ground-based transponder, that allows the aircraft to measure its slant range from the position of the ground-based DME transponder.

Downlink is a transfer of information, generated by an aircraft (not necessarily airborne) and sent to the ground for further processing by an ATC Centre.

Emergency indicators refers to specific Mode A Code values (7500 unlawful interference, 7600 radio failure, 7700 general emergency) or to ADS-C emergency/urgency status (emergency and/or unlawful interference or cancellation of the emergency/urgency).

Extended projected profile (EPP) provides the aircraft’s trajectory intent using ADS-C.

Failure condition terms are defined in AMC 25.1309, FAA AC 23.1309-1( ), AC 27-1B or AC 29-2C.

FANS 1/A refers to Future Air Navigation System 1 or Future Air Navigation System A.

False alert is an incorrect or spurious alert caused by a failure of the alerting system including the sensor.

Field of view refers to either the optimum or maximum vertical and horizontal visual fields from the design eye reference point that can be accommodated with eye rotation only, as described in the figure below.

CS-ACNS Issue 5 Subpart A — General

Annex to EDD 2024/003/R Page 28 of 270

Figure 1 – Optimum and maximum fields of view

Note: This CS defines the optimum and maximum fields of view. As the Federal Aviation Administration

(FAA) defines primary and secondary fields of view in its Advisory Circular (AC) 29-2C, ‘optimum’ should

be read as primary and ‘maximum’ as secondary fields of view.

Flight plan is, in the context of PBN operations, a set of route segments and flight procedures defined and activated by the flight crew in the required navigation performance (RNP) system, relative to an intended flight or a portion of a flight of an aircraft.

FMS selected altitude refers to the level altitude used by the FMS to manage the vertical profile of the aircraft.

Forward looking terrain avoidance (FLTA) looks ahead of the aeroplane along and below the aeroplane’s lateral and vertical flight path and provides suitable alerts if a potential CFIT exists.

Global navigation satellite system (GNSS) refers to a worldwide position and time determination system that includes one or more satellite constellations, aircraft receivers and system integrity monitoring.

CS-ACNS Issue 5 Subpart A — General

Annex to EDD 2024/003/R Page 29 of 270

Ground Comm-B refers to a protocol which allows the interrogator to extract Comm-B replies containing data from a defined source.

Ground speed is the speed of an aircraft relative to the surface, or relative to a horizontal plane at present position.

Group aircraft is a group of aircraft with similar altitude keeping equipment configurations and performance characteristics that are combined together for the purposes of statistical generic performance evaluation. Typically group aircraft refers to aircraft constructed to the same Type Certificate, Service Bulletin or Supplementary Type Certificate.

Hazard refers to a state or set of conditions that together with other conditions in the environment can lead to an accident.

Holding is a predetermined manoeuvre which keeps an aircraft within a specified airspace.

Horizontal velocity refers to the ground speed vector information.

ICAO 24-bit aircraft address is a technical address used by Mode S protocols to identify the transponder on the 1030/1090 MHz RF network. Each aircraft uses a unique 24-bit aircraft address allocated by their state of registry. This address may also be used by other types of avionics equipment for other purpose.

Inertial navigation system/inertial reference unit (INS/IRU) is an aircraft position sensor relying on accelerometers and gyroscopes to estimate position, direction and velocity.

Inertial vertical velocity is the rate of climb measure along the axis estimated using different sources including inertial reference.

Instrument landing system (ILS) is a system using ground-based transmitters and airborne receivers to provide lateral (‘localiser’) and vertical (’glide slope’) guidance to the runway.

Integrity (system integrity) is measured as the probability per operating hour of an undetected failure of a functional element that results in corrupted (erroneous) data, or a failure in the processing as specified, leading to the (partial) loss of otherwise available data.

Lateral navigation (LNAV) refers to area navigation in the horizontal plane.

Magnetic Heading is the angle between the aircraft centreline and magnetic North (angle between the direction to which the aircraft nose is pointing and the magnetic North).

MCP/FCU Selected Altitude is the level selected by the flight crew on the MCP or FCU of the aircraft. This altitude constitutes the level-off target input to the auto-pilot.

Mean sea level (MSL) is a reference for measuring and specifying altitudes in aeronautical information.

Mode S elementary surveillance refers to the use of Mode S surveillance data to downlink aircraft information from airborne installations.

Mode S enhanced surveillance refers to the use of other airborne information in addition to data used for Elementary Surveillance.

Navigation aid refers to a space- or ground-based facility that transmits signals that the aircraft’s navigation system may use to determine its position or its bearing.

Navigation functionality is the detailed capability of the navigation system required to meet the needs of the proposed operations in the airspace.

Navigation specification is a set of aircraft and aircrew requirements needed to support performance- based navigation operations within a defined airspace.

CS-ACNS Issue 5 Subpart A — General

Annex to EDD 2024/003/R Page 30 of 270

Non-group aircraft refers to an aircraft that is not a group aircraft but which is submitted for airworthiness approval on the characteristics of the unique airframe

Nuisance alert is an alert generated by a system that is functioning as designed but which is inappropriate or unnecessary for the particular condition.

Performance-based navigation (PBN) is area navigation based on performance requirements for aircraft operating along an ATS route, on an instrument approach procedure or in designated airspace.

Qualitative probability terms are defined in AMC 25.1309, FAA AC 23.1309-1( ), AC 27-1B or AC 29- 2C.

Required obstacle clearance (ROC) refers to the required vertical clearance expressed in ft between an aircraft and an obstruction.

Required Terrain Clearance (RTC) is a terrain awareness and warning system (TAWS) FLTA mode that alerts when the aeroplane is above the terrain in the aeroplane’s projected flight path, but the projected amount of terrain clearance is considered unsafe for the particular phase of flight.

RNAV (X) specification refers to a navigation specification based on area navigation that does not include the requirement for on-board performance monitoring and alerting, designated by the prefix RNAV, where ‘X’ refers to the lateral navigation accuracy in nautical miles.

RNP (X) specification refers to a navigation specification based on area navigation that includes the requirement for on-board performance monitoring and alerting, designated by the prefix RNP, where ‘X’ refers to the lateral navigation accuracy in nautical miles or the operation type.

RNP system is a system that supports area navigation operations by integrating information from one or more positioning sensors and providing flight crew with the means to define a desired flight path.

Roll angle is the angle of wings compared to horizon representing the angle of rotation around the roll axis going along the centreline of the aircraft.

RVSM flight envelope may be considered to be in two parts; the basic RVSM flight envelope and the full RVSM flight envelope. The basic envelope includes those ranges of Mach numbers and gross weights at which the aircraft can most frequently be expected to operate at RVSM levels (i.e. FL 290 to FL 410 (or maximum attainable altitude)). The full envelope refers to the entire range of Mach numbers, gross weights and altitude values that the aircraft can be operated in RVSM airspace.

RVSM operational flight envelope is the Mach number, W/, and altitude ranges over which an aircraft can be operated in cruising flight within the RVSM airspace.

Satellite-based augmentation system (SBAS) is a wide coverage augmentation system which monitors the GNSS core constellation(s) and provides the user with augmentation information through a satellite-based transmitter.

Search volume is a volume of airspace around the aeroplane’s current and projected path that is used to define a TAWS alert condition.

Static source error (SSE) is the difference between the pressure sensed by the static system at the static port and the undisturbed ambient pressure.

Static source error correction (SSEC) is the correction for the residual static error to ensure compliance with performance requirements.

Terrain cell is a grid of terrain provided by the TAWS database which identifies the highest terrain elevation within a defined geographical area. Terrain cell dimensions and resolution can vary depending on the needs of the TAWS system and availability of data. If a supplier desires, obstacle height can be included in the terrain elevation.

CS-ACNS Issue 5 Subpart A — General

Annex to EDD 2024/003/R Page 31 of 270

Track is the projection on the earth’s surface of the path of an aircraft, the direction of which is usually expressed in degrees from north (true, magnetic or grid).

Track angle rate is the rate of change of the track angle.

Transmit refers to the provision of surveillance data by the transponder.

Transponder is a device that transmits airborne surveillance data spontaneously or when requested. The transmissions are performed on 1090 MHz RF band and the interrogations are received on 1030 MHz RF band using SSR/Mode S protocols. It is also named Secondary Surveillance Radar transponder.

Transponder level is an indication of which Mode S data-link protocols are supported by a transponder. There are 5 transponder levels defined by ICAO.

Transponder register is a transponder data buffer containing different pieces of information. It has 56 bits which are split in different fields. The definition of the transponder registers can be found in ICAO Doc 9871 edition 2 and in transponder MOPS ED-73E with the ICAO document being the reference document in case of conflict. Transponder registers are numbered in hexadecimal (00hex to FFhex). The register number is also known as the BDS code (Comm-B data selector). In this documentation a register is named: register XY16 or register addressed by BDS code X,Y. Outside this document, it is also often referenced as just BDS X,Y.

True track angle is the angle between the track (course over ground or path) of the aircraft and true north.

Uplink is a transfer of information, issued from any ground-based entity (typically: the ATC Centre under which the aircraft is under responsibility) to an aircraft (not necessarily airborne).

Vertical navigation (VNAV) refers to a method of navigation based on a computed vertical path.

VHF omnidirectional range (VOR) is a ground–airborne positioning system based on signals in space transmitted by the VOR ground station to the aircraft VOR receiver to measure its angular position from the ground station.

Warning refers to the level or category of alert for conditions that require immediate flight crew awareness and immediate flight crew response.

Worst case avionics is a combination of tolerance values, specified by the aircraft constructor for the altimetry fit into the aircraft, which gives the largest combined absolute value for residual SSE plus avionics errors.

[Issue: CS-ACNS/2]

[Issue: CS-ACNS/4]

[Issue: CS-ACNS/5]

CS ACNS.A.GEN.010 Instructions for continued airworthiness (See AMC1 ACNS.A.GEN.10)

Instructions for continued airworthiness for each system, part or appliance as specified in this CS ACNS and any information related to the interface of those systems, parts or appliances with the aircraft are to be provided

CS-ACNS Issue 5 Subpart A — General

Annex to EDD 2024/003/R Page 32 of 270

AMC1 ACNS.A.GEN.010 Instructions for Continued Airworthiness (a) Transponder testing

The Instructions for Continued Airworthiness should include the following measures and precautions in order to minimise the possibility of causing nuisance warnings to ACAS equipped aircraft.

(1) When not required, ensure all transponders are selected to ‘OFF‘ or ‘Standby‘.

(2) Before starting any test, contact the local Air Traffic Control Unit and advise them of your intention to conduct transponder testing. Advise the Air Traffic Unit of your start time and test duration. Also inform them of the altitude(s) at which you will be testing, your intended Aircraft Identification (Flight Id) and your intended Mode A code.

Note: Certain altitudes may not be possible due to over flying aircraft.

(3) Set the Mode A code to 7776 (or other Mode A code agreed with Air Traffic Control Unit).

Note: The Mode A code 7776 is reserved for SSR ground transponder monitoring. This code may be used for transponder testing after having received agreement from the Air Traffic Control Unit.

(4) Set the Aircraft Identification (Flight Id) with the first 8 characters of the company name. This is the name of the company conducting the tests.

(5) Set the on-the-ground status for all Mode S replies, except when an airborne reply is required (e.g. for altitude testing).

(6) Where possible, perform the testing inside a hangar to take advantage of any shielding properties it may provide.

(7) As a precaution, use antenna transmission covers whether or not testing is performed inside or outside.

(8) When testing the altitude (Mode C or S) parameter, radiate directly into the ramp test set via the prescribed attenuator.

(9) In between testing, i.e., to transition from one altitude to another, select the transponder to ‘standby’ mode.

(10) If testing transponder parameters other than ‘altitude‘, set altitude to minus 300 m (minus 1 000 feet) or over 18 250 m (60 000 feet). This will minimise the possibility of ACAS warning to airfield and overflying aircraft.

(11) When testing is complete, select the transponder(s) to ‘OFF‘ or ‘Standby’.

(b) Reduced Vertical Separation Minima

When developing the instructions for continued airworthiness, attention should be given to the following items:

(1) All RVSM equipment should be maintained in accordance with the component manufacturers' maintenance instructions and the performance criteria of the RVSM approval data package.

(2) Any repairs, not covered by approved maintenance documents, that may affect the integrity and accuracy of the altimeter system , e.g. those affecting the alignment of pitot/static probes, repairs to dents or deformation around static plates should be subject to a design review which is acceptable to the competent authority.

CS-ACNS Issue 5 Subpart A — General

Annex to EDD 2024/003/R Page 33 of 270

(3) Airframe geometry or skin waviness checks should be performed following repairs or alterations which have an effect on airframe surface and airflow.

(4) The maintenance and inspection programme for the autopilot should ensure continued accuracy and integrity of the automatic altitude control system.

CS ACNS.A.GEN.015 Aircraft documentation (a) The aircraft flight manual (AFM), or similar documentation approved by EASA, provides the list

of aircraft capabilities for which the aircraft is certified in accordance with this CS.

(b) If there are deviations from this CS which result in limitation(s), they are to be clearly stated in the AFM or similar documentation approved by EASA.

[Issue: CS-ACNS/2]

AMC1 ACNS.A.GEN.015(a) Aircraft documentation An acceptable means of compliance in the case of aircraft PBN capabilities is to specify in the documentation which of the following navigation specifications and functionalities the aircraft is certified for:

(a) RNAV 10,

(b) RNAV 5,

(c) RNAV 2,

(d) RNAV 1,

(e) RNP 4,

(f) RNP 2,

(g) RNP 1,

(h) RNP 0.3,

(i) A-RNP,

(j) RNP APCH,

(k) RNP AR (for approach and/or departures),

(l) RF (specify the associated navigation specifications),

(m) FRT,

(n) parallel offset.

[Issue: CS-ACNS/2]

CS ACNS.A.GEN.020 Deviation from equipment standards Any deviations from the ETSO referenced in this CS and associated AMC are to be evaluated to ensure compliance with the CS requirements.

[Issue: CS-ACNS/2]

CS-ACNS Issue 5 Subpart B — Communications (COM)

Section 1 — Voice Channel Spacing (VCS)

Annex to EDD 2024/003/R Page 34 of 270

SUBPART B — COMMUNICATIONS (COM)

SECTION 1 — VOICE CHANNEL SPACING (VCS)

GENERAL

CS ACNS.B.VCS.001 Applicability (See GM1 ACNS.B.VCS.001)

The section provides standards for aircraft voice communication systems operating in the band 117,975-137 MHz.

[Issue: CS-ACNS/4]

GM1 ACNS.B.VCS.001 Applicability Background information on voice communication systems is provided in Appendix A – Background information on voice communication systems.

[Issue: CS-ACNS/4]

SYSTEM FUNCTIONAL REQUIREMENTS

CS ACNS.B.VCS.010 Voice Communication System (see AMC1 ACNS.B.VCS.010)

(a) The voice communication system is capable of 8.33 kHz and 25 kHz channel spacing

(b) Voice communication system is capable of operating with off-set carrier frequencies on 25 kHz channel spacing.

AMC1 ACNS.B.VCS.010 Voice Communication Systems The VCS equipment composing of the system should be approved in accordance with ETSO-2C37e, ETSO-2C38e or ETSO-2C169a.

For the 25 kHz channel spacing off-set carrier frequency operations the equipment composing the system should conform with the requirements of EUROCAE document ED-23C

In airspace where 8.33 kHz channel spacing communication equipment is mandatory and the carriage of two radios is required, both radios should be 8.33 kHz capable (as opposed to one 8.33 kHz system and one 25 kHz system).

CS-ACNS Issue 5 Subpart B — Communications (COM)

Section 1 — Voice Channel Spacing (VCS)

Annex to EDD 2024/003/R Page 35 of 270

SYSTEM PERFORMANCE REQUIREMENTS

CS ACNS.B.VCS.020 Performance requirements Voice communication systems conform to the performance requirements of the following sections of ICAO Annex 10, Volume III, Part 2 (Second Edition – July 2007 incorporating Amendment No 90), Chapter 2, ‘Aeronautical Mobile Service’:

(a) Section 2.1 ‘Air-ground VHF communication system characteristics’;

(b) Section 2.3.1 ‘Transmitting function’; and

(c) Section 2.3.2 ‘Receiving function’ excluding sub-section 2.3.2.8 ‘VDL – Interference Immunity Performance’.

[Issue: CS-ACNS/2]

[Issue: CS-ACNS/4]

CS ACNS.B.VCS.025 Integrity The voice communication systems is designed commensurate with a ‘major’ failure condition.

CS ACNS.B.VCS.030 Continuity (See AMC1 ACNS.B.VCS.030 and GM1 ACNS.B.VCS.030)

The voice communication system, including radio, controls, and antenna(s), is designed to provide a level of continuity that supports the intended operation.

[Issue: CS-ACNS/2]

AMC1 ACNS.B.VCS.030 Continuity For aircraft that are foreseen to be operated within airspace where continuous air-ground voice communications is required, the continuity of the voice communication system is designed to an allowable qualitative probability of ‘remote’, except for

(a) Class I aircraft, as defined in FAA AC 23-1309-1E, certified to a CS-23 amendment prior to 5, and;

(b) aircraft with type code 1SRXXXXX or 2SRXXXXX as defined in ASTM International Standards F3061/F3061M – 17 and certified to CS-23 Amendment 5 or subsequent amendments

where the continuity of the voice communication system may be designed to an allowable qualitative probability of ‘probable’.

[Issue: CS-ACNS/2]

GM1 ACNS.B.VCS.030 Continuity Information about European Union requirements for continuous air-ground communications is provided in Commission Implementing Regulation (EU) No 923/2012 of 26 September 2012 laying down the common rules of the air and operational provisions regarding services and procedures in air navigation. Specific requirements for the operation of radio equipment may be found in the respective States’ aeronautical information publications (AIPs).

CS-ACNS Issue 5 Subpart B — Communications (COM)

Section 1 — Voice Channel Spacing (VCS)

Annex to EDD 2024/003/R Page 36 of 270

Aircraft type codes are defined in ASTM International Standards F3061/F3061M – 17, Standard Specification for Systems and Equipment in Small Aircraft.

[Issue: CS-ACNS/2]

INSTALLATION REQUIREMENTS

CS ACNS.B.VCS.040 Flight Deck Interface (See AMC1 ACNS.B.VCS.040)

A means is provided to:

(a) select the voice communications channel;

(b) display the selected voice communications channel to the flight crew;

(c) indicate the non-operational status or failure of the system without undue delay;

AMC1 ACNS.B.VCS.040 Flight Deck Interface Flight Crew control and display of communication frequencies information should be consistent with the overall crew flight deck design philosophy.

CS-ACNS Issue 5 Subpart B — Communications (COM)

Section 2 — Data Link Services (DLS)

Annex to EDD 2024/003/R Page 37 of 270

SECTION 2 — DATA LINK SERVICES (DLS)

GENERAL

CS ACNS.B.DLS.001 Applicability (See GM1 ACNS.B.DLS.001 and GM2 ACNS.B.DLS.001)

This section provides the airworthiness standards for ATN B1 and ATS B2 limited to the provision of ADS-C EPP.

[Issue: CS-ACNS/5]

GM1 ACNS.B.DLS.001 Applicability ATN B1 data link installations referred to in this section (Section 2) support the data link services ‘ATC Communications Management’ (ACM), ‘ATC Clearances and Information’ (ACL) and ‘ATC Microphone Check’ (AMC) through CPDLC Version 1, as defined in EUROCAE Document ED-110B.

This section also refers to the capability of the data link installations to downlink the extended projected profile (EPP) through ADS-C Version 1, as defined in EUROCAE Document ED-229A, as part of the ATS B2 data link.

The Context Management (CM) application and the DLIC service are prerequisites for the initiation of CPDLC and ADS-C connections.

[Issue: CS-ACNS/4]

[Issue: CS-ACNS/5]

GM2 ACNS.B.DLS.001 Applicability

EASA recognises that ATS B2 in accordance with ED-228A and ED-229A (or later acceptable revisions) is the reference application for data link services in the future. EASA will accept and support applications for the approval of systems that offer ATS B2 data link services in lieu of ATN B1 systems. Applicants are encouraged to contact EASA at their earliest convenience to discuss the means to demonstrate compliance with the relevant applicable standards.

[Issue: CS-ACNS/5]

CS ACNS.B.DLS.005 Installation Requirements (See AMC1 ACNS.B.DLS.005 and GM1 ACNS.B.DLS.005)

The data link system includes a means to enable data communication and flight deck annunciations and controls.

[Issue: CS-ACNS/5]

CS-ACNS Issue 5 Subpart B — Communications (COM)

Section 2 — Data Link Services (DLS)

Annex to EDD 2024/003/R Page 38 of 270

AMC1 ACNS.B.DLS.005 Installation Requirements (VDL Mode 2 Sub- Network)

The data link system should comply with ICAO Document 9776 and ARINC 631-6 for VDL Mode 2 multi-frequency operations.

[Issue: CS-ACNS/5]

GM1 ACNS.B.DLS.005 Data Link System Installation An example of installation may be a system comprising the following components or inputs:

— A VHF Data Radio (VDR) with Mode 2 capability and its associated antenna;

— A Unit for Communication Management;

— A means for crew to be notified of ATS Requests and Clearances, and issue downlink crew requests to controllers or responses to outstanding messages (from controllers);

— An adequate source for UTC time, e.g. a Global Navigation Satellite System (GNSS);

— An adequate source of information for conducted flight plan (e.g. Departure Airport, Destination Airport, Estimated Time of Arrival) and trajectory intent, e.g. Flight Management System (FMS);

— An adequate source of aeroplane position, e.g. Flight Management System (FMS), or a Global Navigation Satellite System (GNSS) or both;

— An adequate source for Air/Ground Status information, e.g. an interface with the landing gear or Flight Management System (FMS) or both;

— An adequate aural attention getter for announcements;

— Adequate indication means of system and service availability;

— Adequate control means for the crew.

[Issue: CS-ACNS/5]

FLIGHT DECK CONTROL AND INDICATION CAPABILITIES

CS ACNS.B.DLS.010 Flight Deck Interface (See AMC1 ACNS.B.DLS.010)

(a) A means is provided:

(1) to inform clearly and unambiguously when uplinked messages are received;

(2) for the flight crew to initiate the logon, to terminate the CPDLC connection and to terminate the ADS-C connections;

(3) for the flight crew to know in real time the identifier of the CPDLC ATS provider(s) and the established ADS-C connections;

(4) to display all messages, with minimal flight crew action, in a format that is easy to comprehend and distinguishable from each other;

CS-ACNS Issue 5 Subpart B — Communications (COM)

Section 2 — Data Link Services (DLS)

Annex to EDD 2024/003/R Page 39 of 270

(5) for the flight crew to respond to ATS messages;

(6) to inform the flight crew that pending or open messages are waiting for a response;

(7) for the flight crew to determine the status of the data link system.

(b) A means is provided to prohibit the deletion, confirmation, or clearance of a message until the entire message is displayed.

[Issue: CS-ACNS/5]

AMC1 ACNS.B.DLS.010 Flight Deck Interface Flight crew control and display of data-link-related information (connectivity status, outstanding messages, etc.) should be consistent with the overall flight deck design philosophy.

Flight crew control and display of data link messages should satisfy integrity and interface design criteria appropriate for the intended purpose. Reference to the applicable CS xx.1309 requirements should be observed.

If a direct interface exists between the data link application and other on-board systems (e.g. flight planning and navigation), a means may be provided for the flight crew to initiate the use of the data contained in the message by the other on-board system. The means provided should be separate from that used to respond to a message.

Flight deck annunciations should be compatible with the overall alerting scheme of the aircraft.

Audible and visual indications should be given by the data link system for each uplinked ATS message, including those messages not displayed immediately because of the lack of crew response to an earlier ATS message. Visual alerts alone may be used for non-ATS messages.

Annunciation of the receipt of a message during critical flight phases should be inhibited until after the critical flight phase. The criteria that define critical flight phases should be consistent with the particular flight deck philosophy and the particular data link services supported.

Means should be provided for the flight crew to list, select, and retrieve the most recent ATS messages received and sent by the flight crew during the flight segment. The status of each message and the time it was received or sent should be accessible.

When CPDLC messages are displayed:

(a) such location should be in the maximum field of view.

(b) messages should be provided in a dedicated display (or in a dedicated window of a display). Shared use of CPDLC and other applications in a common display (or in the same window of a display) should be avoided.

Note 1: (a) and (b) are intended for future extension of CPDLC use beyond the en-route flight phase. Installations not in accordance with these recommendations are liable to be limited for CPDLC operations in the en-route or prior departure flight phase.

Note 2: Where data link messages are displayed on a shared display or on a shared display area, the selection of another display format or function should not result in the loss of uplinked messages which are waiting for a response. In case the pilot is working on another task and a message is uplinked, the uplinked message should not interrupt the current work, nor result in the loss of any uplinked message and/or data entered while accomplishing the other task.

CS-ACNS Issue 5 Subpart B — Communications (COM)

Section 2 — Data Link Services (DLS)

Annex to EDD 2024/003/R Page 40 of 270

(c) messages from the ATSU (Air Traffic Service Unit) should remain displayed until responded, or cleared, or until the flight crew selects another message.

(d) means should be provided for the flight crew to clear uplinked messages from the display. However, this capability should be protected against inadvertent deletion.

(e) If only part of the message is displayed, a visual indication should be provided to the pilot to indicate the presence of the remaining message.

Means should be provided for the flight crew to create, store, retrieve, edit, delete, and send data link messages.

The data link system should indicate when message storage and/or printing is not available.

A flight deck printer could be used as a means of storing data communications messages received or sent during flight.

If a message intended for visual display is greater than the available display area and only part of the message is displayed, a visual indication is to be provided to the pilot to indicate the presence of the remaining message.

The status of each message (i.e. source, time sent, open/closed) should be displayed together with the message.

[Issue: CS-ACNS/4]

[Issue: CS-ACNS/5]

CS ACNS.B.DLS.015 Dual Data Link Capabilities (Dual stack) (See AMC1 ACNS.B.DLS.015)

For aircraft integrating both FANS 1/A and ATN B1 CPDLC applications:

(a) Control and display: Messages with the same intent that are transmitted or received through these technologies are displayed in the same way.

(b) Alerting: Where common alerting is not demonstrable, a means is provided to distinguish between the alerting schemes in a format that is easy to comprehend.

[Issue: CS-ACNS/5]

AMC1.ACNS.B.DLS.015 Dual Data Link Capabilities (Dual stack) Note 1: A dual stack system is either a bilingual system capable of automatically selecting the data

link network or a dual system that uses manual selection with an interlock system.

The data link system should comply with ED-154A, interoperability requirements IR-207, IR-209, IR- 210, IR-211, IR-212, IR-214, and IR-215 to ensure seamless transition between two adjacent ATSUs, one using FANS 1/A+ and the other using ATN B1.

The data link system should demonstrate common accessibility to the FANS 1/A and ATN B1 CPDLC applications. Accessibility demonstration should include common controls (i.e. line select keys) or, where different, the potential to introduce confusion or unacceptable flight crew workload should be evaluated.

The data link system should demonstrate common control and input procedures for retrieving and responding to FANS 1/A and ATN B1 uplink messages.

CS-ACNS Issue 5 Subpart B — Communications (COM)

Section 2 — Data Link Services (DLS)

Annex to EDD 2024/003/R Page 41 of 270

The data link system should demonstrate common control and input procedures for composing and sending FANS 1/A and ATN B1 downlink messages.

The data link system should demonstrate common flight deck indications for incoming FANS 1/A and ATN B1 messages. Where common alerting is not demonstrable, the alerting scheme should be evaluated to ensure that neither confusion nor unnecessary flight crew workload is introduced.

Annunciations and indications should be clear, unambiguous, timely, and consistent with the flight deck philosophy.

Note 2: FANS 1/A standard (ED-100A) identifies the term ‘IMMEDIATELY’, within the phraseology standardised for CPDLC communications. This term is to be understood within the required communications performance (RCP) scope, which for oceanic and remote operations is either 240 seconds or 400 seconds. The use of the terms ‘IMMEDIATELY’ and ‘EXPEDITE’ are not to be confused with the terminology used in material related to CS 25.1322. However, annunciations and indications should allow flight crews to easily identify these messages (associated with Urgent and Distress urgency attribute) among the normal messages.

Flight Deck Display of Messages from either FANS 1/A or ATN B1 CPDLC Applications:

A common flight deck display should be capable of displaying messages with the same operational intent resulting from same message elements that may be implemented differently between FANS 1/A and ATN B1 CPDLC applications. The common format to display FANS 1/A messages may be in accordance with the preferred format denoted in Annex A to ED 122, which is consistent with ICAO Doc 4444, 15th Edition, and ATN B1 message formats.

Dual Stack ATS Data Link System Status Indication:

The system should provide the flight crew with a means to clearly identify the status of different modes of the data link system that affect significantly operational capability. Examples of different modes of data link may include situations where downlink messages are available in one airspace, but not the other, or messages that may or may not be loadable depending on system status, i.e. ATN B1 or FANS 1/A.

ATSU (Air Traffic Service Unit) Connections and Handoffs:

The system should be capable of the following functions:

(1) Proper connection and termination for FANS 1/A ATSU.

(2) Proper connection and termination for ATN B1 ATSU.

(3) Transfer to next data authority (e.g. FANS 1/A ATSU to ATN B1 ATSU), in both directions. This should include proper connection, maintenance of connection and connection termination protocol to ensure that the aircraft does not hold two simultaneous active CPDLC connections except for the transfer to the next data authority.

(4) Ability for flight crew to manually terminate existing connection and initiate a DLIC ‘logon’ in both directions (i.e. FANS 1/A-to-ATN B1 and ATN B1-to-FANS 1/A).

(5) Ability for flight crew to verify current and next facility designation or name.

Note 3: FAA AC 20-140C provides adequate guidance related to the application interoperability, sub- networks and performance designators (refer to Tables 5.1 and 5.2).

[Issue: CS-ACNS/5]

CS-ACNS Issue 5 Subpart B — Communications (COM)

Section 2 — Data Link Services (DLS)

Annex to EDD 2024/003/R Page 42 of 270

ATN B1 DATA LINK AND ADS-C EPP DOWNLINK CAPABILITY

CS ACNS.B.DLS.020 Data Link Capabilities (See AMC1 ACNS.B.DLS.020, GM1 ACNS.B.DLS.020 and GM2 ACNS.B.DLS.020)

The data link system provides the following capabilities:

(a) Data Link Initiation Capability (DLIC);

(b) ATC Communications Management (ACM);

(c) ATC Clearances and Information (ACL);

(d) ATC Microphone Check (AMC); and

(e) Downlink of ADS-C EPP.

[Issue: CS-ACNS/5]

AMC1 ACNS.B.DLS.020 Data Link Capabilities When the aircraft has no CPDLC Current Data Authority, the aircraft’s data link equipment should provide crew members that enter the airspace of a data-link-equipped ATS unit with the capability to initiate a DLIC ‘Logon’ function (e.g. send a CMLogonRequest message) with the applicable ATS unit, in order to identify the aircraft and initiate the use of data link services.

[Issue: CS-ACNS/5]

GM1 ACNS.B.DLS.020 Data Link Capabilities Data link capabilities should be demonstrated using a representative ground data link system or a ground data link system simulator able to support the transactions and information exchange defined in Subpart B, Section 2.

(a) Data Link Initiation Capability (DLIC) Service

The DLIC service enables the exchange of information between aircraft and ground data link equipment, necessary for the establishment of data link communications. It ensures:

(1) the unambiguous association of flight data from the aircraft with flight plan data used by an ATS unit;

(2) the exchange of the supported air–ground application type and version information;

(3) the delivery of the addressing information of the entity hosting the application.

(b) ATC Communications Management (ACM) Service

The ACM service provides automated assistance to flight crews for conducting the transfer of ATC communications (voice and data). It includes:

(1) the initial establishment of CPDLC with an ATS unit;

(2) the CPDLC ATC transfer instruction from one ATS unit to the next ATS unit;

(3) the CPDLC ATC instructions for a change in voice channel;

(4) the normal termination of CPDLC with an ATS unit.

(c) ATC Clearances and Information (ACL) Service

CS-ACNS Issue 5 Subpart B — Communications (COM)

Section 2 — Data Link Services (DLS)

Annex to EDD 2024/003/R Page 43 of 270

The ACL service provides flight crews with the ability to:

(1) send requests and reports to air traffic controllers;

(2) receive clearances, instructions and notifications issued by air traffic controllers to flight crews.

(d) ATC Microphone Check (AMC) Service

The AMC service provides CPDLC ATC instructions to flight crews requesting them to verify the status of their voice communication equipment.

(e) Downlink of ADS-C EPP

ADS-C provides the capabilities to:

(1) establish and terminate ADS-C contracts (demand, periodic, event);

(2) downlink the EPP report commensurate with the type of ADS-C contract.

[Issue: CS-ACNS/4]

[Issue: CS-ACNS/5]

GM2 ACNS.B.DLS.020 Data Link Capabilities — Testing

Testing demonstrations could be based on two main steps:

— Equipment testing (performed by the equipment manufacturer) using adequate simulation testing tools.

— System testing at system test bench and/or at aircraft test level (either on ground or in flight).

Equipment qualification testing data may be reused from the avionics manufacturer, provided that full and unrestricted access to the compliance data is established and maintained. However, the applicant remains responsible for all test data used in the course of compliance demonstration.

[Issue: CS-ACNS/5]

CS ACNS.B.DLS.025 Protection mechanism (See AMC1 ACNS.B.DLS.025)

A means is provided to protect the integrity of the message.

[Issue: CS-ACNS/5]

AMC1 ACNS.B.DLS.025 Protection mechanism The data link system that complies with EUROCAE Documents ED-110B and ED-229A satisfies the requirement.

[Issue: CS-ACNS/5]

CS-ACNS Issue 5 Subpart B — Communications (COM)

Section 2 — Data Link Services (DLS)

Annex to EDD 2024/003/R Page 44 of 270

SYSTEM PERFORMANCE REQUIREMENTS

CS ACNS.B.DLS.030 Integrity The data link system integrity is designed commensurate with a ‘major’ failure condition.

[Issue: CS-ACNS/5]

CS ACNS.B.DLS.035 Data Link System Continuity (See AMC1 ACNS.B.DLS.035 and GM1 ACNS.B.DLS.035)

The data link system is designed to provide a level of continuity that supports the intended operation.

[Issue: CS-ACNS/4]

[Issue: CS-ACNS/5]

AMC1 ACNS.B.DLS.035 Data Link System Continuity The loss of the data link system function is considered to be a minor failure condition.

[Issue: CS-ACNS/4] [Issue: CS-ACNS/5]

GM1 ACNS.B.DLS.035 Data Link System Continuity The definition of continuity in CS-ACNS is different from the definition of continuity in EUROCAE Documents ED-120 and ED-228A. Throughout CS-ACNS, continuity (system continuity) refers to ‘the probability that a system will perform its required function without unscheduled interruption’.

In the context of ED-120 and ED-228A, ‘continuity’ refers to the probability that the transaction is completed before the transaction expiration time, assuming that the communication system is available when the transaction is initiated.

[Issue: CS-ACNS/4] [Issue: CS-ACNS/5]

TIME

CS ACNS.B.DLS.040 Universal Time Coordinated (UTC) (See AMC1 ACNS.B.DLS.040)

For time synchronisation, a valid UTC time source is used.

Wherever time is utilised in the application of data link communications, it is accurate to within 1 second of UTC.

[Issue: CS-ACNS/5]

AMC1 ACNS.B.DLS.040 Universal Time Coordinated (UTC) A Global Navigation Satellite System (GNSS) sensor provides an acceptable source of synchronised UTC time.

CS-ACNS Issue 5 Subpart B — Communications (COM)

Section 2 — Data Link Services (DLS)

Annex to EDD 2024/003/R Page 45 of 270

[Issue: CS-ACNS/5]

DATA LINK INITIATION CAPABILITY (DLIC) SERVICE MESSAGES

CS ACNS.B.DLS.050 DLIC Uplink Messages (See AMC1 ACNS.B.DLS.050)

The data link system is capable of receiving and processing the following messages for the DLIC Logon and Contact functions:

Function Message

Logon CMLogonResponse

Contact CMContactRequest

[Issue: CS-ACNS/5]

AMC1 ACNS.B.DLS.050 DLIC Uplink Messages The data link system should comply with EUROCAE Document ED-110B, Section 2.2.1 or ED-229A, Section 2.4.1.

Note 1: The B1 and B2 CM applications are fully compatible.

Note 2: Although ICAO Doc 9705 is not maintained any more, the DLIC message syntax should comply with ICAO Doc 9705 as referred to in ED-110B.

[Issue: CS-ACNS/5]

CS ACNS.B.DLS.055 DLIC Downlink Messages (See AMC1 ACNS.B.DLS.055)

The data link system is capable of sending the following messages for the DLIC Logon and Contact functions:

Function Message

Logon CMLogonRequest

Contact CMContactResponse

[Issue: CS-ACNS/5]

AMC1 ACNS.B.DLS.055 DLIC Downlink Messages The data link system should comply with EUROCAE Document ED-110B, Section 2.2.1 or ED-229A, Section 2.4.1.

Note 1: The B1 and B2 CM applications are fully compatible.

Note 2: Although ICAO Doc 9705 is not maintained any more, the DLIC message syntax should comply with ICAO Doc 9705 as referred to in ED-110B.

[Issue: CS-ACNS/5]

CS-ACNS Issue 5 Subpart B — Communications (COM)

Section 2 — Data Link Services (DLS)

Annex to EDD 2024/003/R Page 46 of 270

CS ACNS.B.DLS.060 DLIC initiation when in ‘CPDLC inhibited’ state (uplink) When the data link system is in the ‘CPDLC inhibited’ state, a DLIC Contact Request is processed but the system remains in the ‘CPDLC inhibited’ state.

[Issue: CS-ACNS/4] [Issue: CS-ACNS/5]

CPDLC MESSAGES

CS ACNS.B.DLS.070 CPDLC Uplink Messages (See AMC1 ACNS.B.DLS.070, GM1 ACNS.B.DLS.070 and GM2 ACNS.B.DLS.070)

The data link system is capable of receiving, processing and displaying the following message elements:

ID Message

UM0 UNABLE

UM1 STANDBY

UM3 ROGER

UM4 AFFIRM

UM5 NEGATIVE

UM19 MAINTAIN [level]

UM20 CLIMB TO [level]

UM23 DESCEND TO [level]

UM26 CLIMB TO REACH [level] BY [time]

UM27 CLIMB TO REACH [level] BY [position]

UM28 DESCEND TO REACH [level] BY [time]

UM29 DESCEND TO REACH [level] BY [position]

UM46 CROSS [position] AT [level]

UM47 CROSS [position] AT OR ABOVE [level]

UM48 CROSS [position] AT OR BELOW [level]

UM51 CROSS [position] AT [time]

UM52 CROSS [position] AT OR BEFORE [time]

UM53 CROSS [position] AT OR AFTER [time]

UM54 CROSS [position] BETWEEN [time] AND [time]

UM55 CROSS [position] AT [speed]

UM61 CROSS [position] AT AND MAINTAIN [level] AT [speed]

UM64 OFFSET [specifiedDistance] [direction] OF ROUTE

UM72 RESUME OWN NAVIGATION

UM74 PROCEED DIRECT TO [position]

UM79 CLEARED TO [position] VIA [routeClearance]

UM80 CLEARED [routeClearance]

UM82 CLEARED TO DEVIATE UP TO [specifiedDistance] [direction] OF ROUTE

UM92 HOLD AT [position] AS PUBLISHED MAINTAIN [level]

CS-ACNS Issue 5 Subpart B — Communications (COM)

Section 2 — Data Link Services (DLS)

Annex to EDD 2024/003/R Page 47 of 270

UM94 TURN [direction] HEADING [degrees]

UM96 CONTINUE PRESENT HEADING

UM106 MAINTAIN [speed]

UM107 MAINTAIN PRESENT SPEED

UM108 MAINTAIN [speed] OR GREATER

UM109 MAINTAIN [speed] OR LESS

UM116 RESUME NORMAL SPEED

UM117 CONTACT [unitname] [frequency]

UM120 MONITOR [unitname] [frequency]

UM123 SQUAWK [code]

UM133 REPORT PRESENT LEVEL

UM148 WHEN CAN YOU ACCEPT [level]

UM157 CHECK STUCK MICROPHONE [frequency]

UM159 ERROR [errorInformation]

UM162 SERVICE UNAVAILABLE

UM165 THEN

UM171 CLIMB AT [verticalRate] MINIMUM

UM172 CLIMB AT [verticalRate] MAXIMUM

UM173 DESCEND AT [verticalRate] MINIMUM

UM174 DESCEND AT [verticalRate] MAXIMUM

UM179 SQUAWK IDENT

UM183 [freetext]

UM190 FLY HEADING [degrees]

UM196 [freetext]

UM203 [freetext]

UM205 [freetext]

UM211 REQUEST FORWARDED

UM213 [facilitydesignation] ALTIMETER [altimeter]

UM215 TURN [direction] [degrees]

UM222 NO SPEED RESTRICTION

UM231 STATE PREFERRED LEVEL

UM232 STATE TOP OF DESCENT

UM237 REQUEST AGAIN WITH NEXT UNIT

The data link system is capable of receiving and processing the following message elements:

UM160 NEXT DATA AUTHORITY [facility]

UM227 LOGICAL ACKNOWLEDGEMENT

[Issue: CS-ACNS/4] [Issue: CS-ACNS/5]

AMC1 ACNS.B.DLS.070 CPDLC Uplink Messages The data link system should comply with EUROCAE Document ED-110B.

Note: Although ICAO Doc 9705 is not maintained any more, the CPDLC message syntax should comply with ICAO Doc 9705 as referred to in ED-110B.

CS-ACNS Issue 5 Subpart B — Communications (COM)

Section 2 — Data Link Services (DLS)

Annex to EDD 2024/003/R Page 48 of 270

The data link system should prepare the appropriate response downlink message to a received uplink message in compliance with EUROCAE Document ED-110B, Section 2.2.3.3, Table 2-4.

The aircraft data link system should also handle unsupported messages (i.e. uplink messages not referenced in CS ACNS.B.DLS.070) as specified in EUROCAE Document ED-110B, Section 3.3.7.6.

[Issue: CS-ACNS/5]

GM1 ACNS.B.DLS.070 Uplink Messages The following table associates uplink CPDLC messages to data link services.

ID Message ACM ACL AMC

UM0 UNABLE x

UM1 STANDBY x

UM3 ROGER x

UM4 AFFIRM x

UM5 NEGATIVE x

UM19 MAINTAIN [level] x

UM20 CLIMB TO [level] x

UM23 DESCEND TO [level] x

UM26 CLIMB TO REACH [level] BY [time] x

UM27 CLIMB TO REACH [level] BY [position] x

UM28 DESCEND TO REACH [level] BY [time] x

UM29 DESCEND TO REACH [level] BY [position] x

UM46 CROSS [position] AT [level] x

UM47 CROSS [position] AT OR ABOVE [level] x

UM48 CROSS [position] AT OR BELOW [level] x

UM51 CROSS [position] AT [time] x

UM52 CROSS [position] AT OR BEFORE [time] x

UM53 CROSS [position] AT OR AFTER [time] x

UM54 CROSS [position] BETWEEN [time] AND [time] x

UM55 CROSS [position] AT [speed] x

UM61 CROSS [position] AT AND MAINTAIN x

UM64 OFFSET [specifiedDistance] [direction] OF ROUTE x

UM72 RESUME OWN NAVIGATION x

UM74 PROCEED DIRECT TO [position] x

UM79 CLEARED TO [position] VIA [routeClearance] x

UM80 CLEARED [routeClearance] x

UM82 CLEARED TO DEVIATE UP TO [specifiedDistance] [direction] OF ROUTE

x

UM92 HOLD AT [position] AS PUBLISHED MAINTAIN [level] x

UM94 TURN [direction] HEADING [degrees] x

UM96 CONTINUE PRESENT HEADING x

UM106 MAINTAIN [speed] x

UM107 MAINTAIN PRESENT SPEED x

UM108 MAINTAIN [speed] OR GREATER x

UM109 MAINTAIN [speed] OR LESS x

UM116 RESUME NORMAL SPEED x

CS-ACNS Issue 5 Subpart B — Communications (COM)

Section 2 — Data Link Services (DLS)

Annex to EDD 2024/003/R Page 49 of 270

UM117 CONTACT [unitname] [frequency] x

UM120 MONITOR [unitname] [frequency] x

UM123 SQUAWK [code] x

UM133 REPORT PRESENT LEVEL x

UM148 WHEN CAN YOU ACCEPT [level] x

UM157 CHECK STUCK MICROPHONE [frequency] x

UM159 ERROR [errorInformation] x x

UM160 NEXT DATA AUTHORITY [facility] x

UM162 SERVICE UNAVAILABLE x

UM165 THEN x

UM171 CLIMB AT [verticalRate] MINIMUM x

UM172 CLIMB AT [verticalRate] MAXIMUM x

UM173 DESCEND AT [verticalRate] MINIMUM x

UM174 DESCEND AT [verticalRate] MAXIMUM x

UM179 SQUAWK IDENT x

UM183 [freetext] x x x

UM190 FLY HEADING [degrees] x

UM196 [freetext] x

UM203 [freetext] x

UM205 [freetext] x

UM211 REQUEST FORWARDED x

UM213 [facilitydesignation] ALTIMETER [altimeter] x

UM215 TURN [direction] [degrees] x

UM222 NO SPEED RESTRICTION x

UM227 LOGICAL ACKNOWLEDGEMENT x x

UM231 STATE PREFERRED LEVEL x

UM232 STATE TOP OF DESCENT x

UM237 REQUEST AGAIN WITH NEXT UNIT x x

[Issue: CS-ACNS/5]

GM2 ACNS.B.DLS.070 Uplink Messages The above ACL messages correspond to the common subset of ACL messages defined in EUROCAE Document ED-120, Section 5.2.1.1.5.

[Issue: CS-ACNS/5]

CS ACNS.B.DLS.075 CPDLC Downlink Messages (See AMC1 ACNS.B.DLS.075, GM1 ACNS.B.DLS.075, GM2 ACNS.B.DLS.075 and GM3 ACNS.B.DLS.075)

The data link system is capable of preparing and sending the following downlink message elements:

ID Message

DM0 WILCO

DM1 UNABLE

DM2 STANDBY

DM3 ROGER

CS-ACNS Issue 5 Subpart B — Communications (COM)

Section 2 — Data Link Services (DLS)

Annex to EDD 2024/003/R Page 50 of 270

DM4 AFFIRM

DM5 NEGATIVE

DM6 REQUEST [level]

DM18 REQUEST [speed]

DM22 REQUEST DIRECT TO [position]

DM32 PRESENT LEVEL [level]

DM62 ERROR [errorInformation]

DM63 NOT CURRENT DATA AUTHORITY

DM65 DUE TO WEATHER

DM66 DUE TO AIRCRAFT PERFORMANCE

DM81 WE CAN ACCEPT [level] AT [time]

DM82 WE CANNOT ACCEPT [level]

DM98 [freetext]

DM99 CURRENT DATA AUTHORITY

DM100 LOGICAL ACKNOWLEDGEMENT

DM106 PREFERRED LEVEL [level]

DM107 NOT AUTHORISED NEXT DATA AUTHORITY

DM109 TOP OF DESCENT [time]

[Issue: CS-ACNS/4] [Issue: CS-ACNS/5]

AMC1 ACNS.B.DLS.075 Downlink Messages The data link system should comply with EUROCAE Document ED-110B.

Note: Although ICAO Doc 9705 is not maintained any more, the CPDLC message syntax should comply with ICAO Doc 9705 as referred to in ED-110B.

The data link system should prepare the appropriate downlink message response to a received uplink message in compliance with EUROCAE Document ED-110B, Section 2.2.3.3, Table 2-4.

[Issue: CS-ACNS/4] [Issue: CS-ACNS/5]

GM1 ACNS.B.DLS.075 Downlink Messages The following table associates downlink messages with data link services.

ID Message ACM ACL AMC

DM0 WILCO x x

DM1 UNABLE x x

DM2 STANDBY x x

DM3 ROGER x

DM4 AFFIRM x

DM5 NEGATIVE x

DM6 REQUEST [level] x

DM18 REQUEST [speed] x

DM22 REQUEST DIRECT TO [position] x

DM32 PRESENT LEVEL [level] x

DM62 ERROR [errorInformation] x x

CS-ACNS Issue 5 Subpart B — Communications (COM)

Section 2 — Data Link Services (DLS)

Annex to EDD 2024/003/R Page 51 of 270

DM63 NOT CURRENT DATA AUTHORITY x

DM65 DUE TO WEATHER x

DM66 DUE TO AIRCRAFT PERFORMANCE x

DM81 WE CAN ACCEPT [level] AT [time] x

DM82 WE CANNOT ACCEPT [level] x

DM98 [freetext] x x

DM99 CURRENT DATA AUTHORITY x

DM100 LOGICAL ACKNOWLEDGEMENT x x

DM106 PREFERRED LEVEL [level] x

DM107 NOT AUTHORISED NEXT DATA AUTHORITY x x

DM109 TOP OF DESCENT [time] x

[Issue: CS-ACNS/4] [Issue: CS-ACNS/5]

GM2 ACNS.B.DLS.075 Downlink Messages The above ACL messages correspond to the common subset of ACL messages defined in EUROCAE Document ED-120 Section 5.2.1.1.5.

[Issue: CS-ACNS/5]

GM3 ACNS.B.DLS.075 Optional ACL Downlink Messages The data link system may also allow sending the following ACL messages defined in EUROCAE Document ED-120 Section 5.2.1.1.5.

Note 1: Although ICAO Doc 9705 is not maintained any more, the CPDLC message syntax should comply with ICAO Doc 9705 as referred to in ED-110B.

ID Message

DM9 REQUEST CLIMB TO [level]

DM10 REQUEST DESCENT TO [level]

DM27 REQUEST WEATHER DEVIATION UP TO [specifiedDistance] [direction] OF ROUTE

Note 2: To prevent costly retrofitting, implementation of the above optional messages is highly recommended.

[Issue: CS-ACNS/5]

ADS-C EPP DATA

CS ACNS.B.DLS.077 ADS-C EPP Data

(See AMC1 ACNS.B.DLS.077)

CS-ACNS Issue 5 Subpart B — Communications (COM)

Section 2 — Data Link Services (DLS)

Annex to EDD 2024/003/R Page 52 of 270

The data link system is capable of:

— receiving and processing ADS-C contract requests (demand, periodic, event); and

— preparing and downlinking EPP through ADS-C contract reports according to the ADS-C contract requests.

[Issue: CS-ACNS/5]

AMC1 ACNS.B.DLS.077 ADS-C EPP Data

The data link system should comply with EUROCAE Document ED-228A, Section 6.2 and EUROCAE ED-229A, Sections 3.2 and 5.3 to support the exchange of EPP data.

[Issue: CS-ACNS/5]

DATA LINK SERVICES AND ADS-C EPP DOWNLINK REQUIREMENTS

CS ACNS.B.DLS.080 Data Link Initiation Capability (DLIC) Service (See AMC1 ACNS.B.DLS.080 and GM1 ACNS.B.DLS.080)

The data link system for DLIC service complies with EUROCAE Documents ED-120, Sections 4.1, 4.2.2 and 4.3.2, and ED-110B, Sections 2.2.1 and 4.1.

[Issue: CS-ACNS/4] [Issue: CS-ACNS/5]

AMC1 ACNS.B.DLS.080 Data Link Initiation Capability (DLIC) Service (a) The data link aircraft equipment DLIC Logon function should comply with the aircraft system

PR-DLIC-Init-ETRCTP and PR-DLIC-Init-TT performance values, respectively 6 seconds and 4 seconds, as specified in EUROCAE Document ED-120 Table A-3.

(b) The data link aircraft equipment DLIC Contact function should comply with the aircraft system PR-DLIC-Cont-ETRCTP and PR-DLIC-Cont-TT performance values, respectively 12 seconds and 8 seconds, as specified in EUROCAE Document ED-120 Table A-3.

(c) The data link system should:

(1) not permit data link services when there are incompatible DLIC version numbers;

(2) reinitiate the service with the applicable ATSUs when any of the application or flight information changes;

(3) insert the relevant initiation data in the initiation messages;

(4) not affect the intent of the DLIC message during processing (data entry/encoding/ transmitting/decoding/displaying).

[Issue: CS-ACNS/5]

GM1 ACNS.B.DLS.080 Data Link Initiation Capability (DLIC) Service The Performance Tables in EUROCAE Document ED-120 for DLIC service (Table 4-8 and Table 4-9) provide the allocated values for the required transaction performance.

CS-ACNS Issue 5 Subpart B — Communications (COM)

Section 2 — Data Link Services (DLS)

Annex to EDD 2024/003/R Page 53 of 270

A detailed allocation for aircraft delays is provided in EUROCAE Document ED-120 Annex A Table A-3.

[Issue: CS-ACNS/5]

CS ACNS.B.DLS.085 ATC Communications Management (ACM) Service (See AMC1 ACNS.B.DLS.085 and GM1 ACNS.B.DLS.085)

The data link system for ACM service complies with EUROCAE Document ED-120, Sections 5.1.1, 5.1.2.3 (excluding the requirements relating to downstream clearance) and 5.1.3.2.

[Issue: CS-ACNS/4] [Issue: CS-ACNS/5]

AMC1 ACNS.B.DLS.085 ATC Communications Management (ACM) Service The data link system for ACM service should comply with the aircraft system PR-ACM-ETRCTP and PR-ACM-TT performance values, respectively 6 seconds and 4 seconds, as specified in EUROCAE Document ED-120 Annex A Table A-3.

[Issue: CS-ACNS/5]

GM1 ACNS.B.DLS.085 ATC Communications Management (ACM) Service The Performance Tables in EUROCAE Document ED-120 for ACM service (Table 5-21) provide the allocated values for the required transaction performance.

A detailed allocation for aircraft delays is provided in EUROCAE Document ED-120 Annex A Table A-3.

[Issue: CS-ACNS/5]

CS ACNS.B.DLS.090 ACL Service Safety Requirements (See AMC1 ACNS.B.DLS.090 and GM1 ACNS.B.DLS.090)

The data link system for ACL service complies with EUROCAE Document ED-120, Sections 5.2.1, 5.2.2.3 and 5.2.3.2.

[Issue: CS-ACNS/4] [Issue: CS-ACNS/5]

AMC1 ACNS.B.DLS.090 ATC Clearances and Information (ACL) Service The data link system for ACL service should comply with the aircraft system PR-ACL-ETRCTP and PR-ACL-TT performance values, respectively 6 seconds and 4 seconds, as specified in EUROCAE Document ED-120 Annex A Table A-3.

[Issue: CS-ACNS/5]

CS-ACNS Issue 5 Subpart B — Communications (COM)

Section 2 — Data Link Services (DLS)

Annex to EDD 2024/003/R Page 54 of 270

GM1 ACNS.B.DLS.090 ATC Clearances and Information (ACL) Service The Performance Tables in EUROCAE Document ED-120 for ACL service (Table 5-31 and Table 5-32) provide the allocated values for the required transaction performance.

A detailed allocation for aircraft delays is provided in EUROCAE Document ED-120 Annex A Table A-3.

[Issue: CS-ACNS/5]

CS ACNS.B.DLS.095 ATC Microphone Check (AMC) Service The data link system for AMC service complies with EUROCAE Document ED-120, Sections 5.3.1, 5.3.2.3 and 5.3.3.2.

[Issue: CS-ACNS/4] [Issue: CS-ACNS/5]

CS ACNS.B.DLS.097 ADS-C EPP Safety and Performance Requirements

(See AMC1 ACNS.B.DLS.097)

The data link system for ADS-C EPP complies with EUROCAE Document ED-228A, Sections 6.1, 6.3.1 and 6.3.2.

[Issue: CS-ACNS/5]

AMC1 ACNS.B.DLS.097 ADS-C EPP Safety and Performance Requirements

The required surveillance performance (RSP) 160 should apply, in accordance with the intended use of ADS-C EPP within the SES.

[Issue: CS-ACNS/5]

INTEROPERABILITY REQUIREMENTS

CS ACNS.B.DLS.100 Network Layer Requirements (See AMC1 ACNS.B.DLS.100 and GM1 ACNS.B.DLS.100)

The ATN Router conforms to Class 6 with the capability to support inter-domain routing protocol (IDRP).

[Issue: CS-ACNS/5]

CS-ACNS Issue 5 Subpart B — Communications (COM)

Section 2 — Data Link Services (DLS)

Annex to EDD 2024/003/R Page 55 of 270

AMC1 ACNS.B.DLS.100 Network Layer Requirements The ATN Router should comply with ICAO Document 9705 (Edition 2), Sections 5.2.4.1 and 5.2.4.3, with an IDRP Hold Time value of 900 seconds.

[Issue: CS-ACNS/5]

GM1 ACNS.B.DLS.100 Network Layer Requirements Compression Schemes

Airborne ATN Routers may implement several distinct, yet complementary, compression schemes.

Airborne ATN Routers should support the CLNP Header Compression (also known as ‘LREF Compression’). Other compression schemes in ICS are optional.

In addition to the CLNP Header Compression, data link ATN Routers that claims support for optional DEFLATE compression should also support ICAO PDU M0070002 (‘Interoperability impact when deflate compression is used. Non-compliance with Zlib’).

[Issue: CS-ACNS/5]

CS ACNS.B.DLS.105 Transport Layer Protocol Requirements (See AMC1 ACNS.B.DLS.105 and GM1 ACNS.B.DLS.105)

The ATN Connection Oriented Transport Protocol (COTP), conforms to Transport Protocol Class 4.

[Issue: CS-ACNS/5]

AMC1 ACNS.B.DLS.105 Transport Layer Protocol Requirements The ATN End System of the data link aircraft equipment should comply with Transport Protocol Class 4 specified in ICAO Document 9705 (Edition 2), Sub-volume V, Section 5.5.2.

The data link aircraft equipment should implement Transport Protocol Class 4 parameter settings in accordance with the following table:

Scope Parameter Definition Value

Inactivity Inactivity time (I) A bound for the time after which a transport entity will, if it does not receive a Transport Protocol Data Unit (TPDU), initiate the release procedure to terminate the transport connection.

360 seconds

Retransmission Retransmission time (T1)

A bound for the maximum time the transport entity will wait for acknowledgement before retransmitting a TPDU. The retransmission time is adaptive.

Initial value 30 seconds

Maximum Retransmission (N)

Maximum number of TPDU retransmissions. 7

Window Window time (W) A bound for the maximum time a transport entity will wait before retransmitting up-to- date window information.

120 seconds

CS-ACNS Issue 5 Subpart B — Communications (COM)

Section 2 — Data Link Services (DLS)

Annex to EDD 2024/003/R Page 56 of 270

Flow Control Local Acknowledgement delay (Al)

A bound for the maximum time which can elapse between the receipt of a TPDU by the local transport entity from the network layer and the transmission of the corresponding acknowledgement.

1 second

[Issue: CS-ACNS/5]

GM1 ACNS.B.DLS.105 Transport Layer Protocol Requirements Transport Protocol Classes

ICAO Doc 9705 (Edition 2), Sub-volume V, Section 5.5 identifies both Connection-Oriented and Connection-Less Transport Protocols (as specified in ISO/IEC 8073 for COTP and ISO/IEC 8602 for CLTP respectively). The only mandated support is for COTP (i.e. CLTP support is not required).

In addition, ISO/IEC 8073 identifies five distinct possible implementations for COTP support, ranging from Class 0 (the less constraining to implement, but also the less reliable) to Class 4 (most reliable). The fifth class, i.e. COTP Class 4 (also known as ‘TP4’), is the only mandated implementation (all other implementation classes are useless for the ATN COTP support).

In the ATN Baseline 1 SARPs (i.e. ICAO Doc 9705 (Edition 2)), Transport Class 4 — also known as ‘TP4’ — is as specified in ISO 8073 that mandates support for a 16-bit checksum. Such checksum is considered insufficient to detect, and thus compensate, all potential misdeliveries of CLNP Packets by the underlying network routers. The analysis that concluded TP4 inability to detect and compensate all CLNP misdeliveries is available in ICAO PDR M00040002. The use of a 32-bit long checksum is identified as a solution to address this potential issue.

[Issue: CS-ACNS/5]

CS ACNS.B.DLS.110 Session Layer Requirements (See AMC1 ACNS.B.DLS.110)

The ATN Session protocol is capable of supporting the following session protocol data units (SPDUs):

Abbreviation Full SPDU Name

SCN Short Connect

SAC Short Accept

SACC Short Accept Continue

SRF Short Refuse

SRFC Short Refuse Continue

[Issue: CS-ACNS/5]

AMC1 ACNS.B.DLS.110 Session Layer Requirements (a) The ATN End System of the data link aircraft equipment should support a Session Protocol as

specified in ICAO Doc 9705 (Edition 2), Sub-volume IV, Section 4.4 including ISO/IEC 8327 Technical Corrigendum 1 (2002) listed in the following table.

Value (Hex) Abbreviation Full SPDU Name

E8 SCN Short Connect

F0 SAC Short Accept

D8 SACC Short Accept Continue

CS-ACNS Issue 5 Subpart B — Communications (COM)

Section 2 — Data Link Services (DLS)

Annex to EDD 2024/003/R Page 57 of 270

E0-E3 SRF Short Refuse E0: TC retained, transient refusal E1: TC retained, persistent refusal E2: TC released, transient refusal E3: TC released, persistent refusal

A0 SRFC Short Refuse Continue

(b) The ATN End System Session Protocol of the data link system should make use of the value ‘E3’ to encode the Short Refuse (SRF) SPDU.

[Issue: CS-ACNS/5]

CS ACNS.B.DLS.115 Presentation Layer Requirements (See AMC1 ACNS.B.DLS.115)

The ATN Presentation protocol is capable of supporting the presentation protocol data units (PPDUs) listed in the following table:

Abbreviation Full PPDU Name

SHORT-CP Short Presentation Connect, unaligned PER

SHORT-CPA Short Presentation Connect Accept, unaligned PER

SHORT-CPR Short Presentation Connect Reject

[Issue: CS-ACNS/4] [Issue: CS-ACNS/5]

AMC1 ACNS.B.DLS.115 Presentation Layer Requirements (a) The ATN End System of the data link aircraft equipment should support a Presentation Protocol

as specified in ICAO Doc 9705 (Edition 2), Sub-volume IV, Section 4.5, and listed in the following table:

Value (Hex) Abbreviation Full PPDU Name

02 SHORT-CP Short Presentation Connect, unaligned PER

02 SHORT-CPA Short Presentation Connect Accept, unaligned PER

x2 SHORT-CPR Short Presentation Connect Reject Where x = reason code: 02: presentation-user 12: reason not specified (transient) 22: temporary congestion (transient) 32: local limit exceeded (transient) 42: called presentation address unknown (permanent) 52: protocol version not supported (permanent) 62: default context not supported (permanent) 72: user data not readable (permanent)

(b) The ATN End System Presentation Protocol of the aircraft’s data link equipment should make use of the value ‘02’ to encode the SHORT-CPR PPDU.

[Issue: CS-ACNS/5]

CS-ACNS Issue 5 Subpart B — Communications (COM)

Section 2 — Data Link Services (DLS)

Annex to EDD 2024/003/R Page 58 of 270

CS ACNS.B.DLS.120 Application Layer Requirements (See AMC1 ACNS.B.DLS.120 and GM1 ACNS.B.DLS.120)

The Application Layer is application-independent (also known as ‘Layer 7a’) and composed of a Control Function supporting operations of an Application Control Service Element (ACSE).

[Issue: CS-ACNS/5]

AMC1 ACNS.B.DLS.120 Application Layer Requirements (a) The ATN End System of the data link system should support an ATN Control Function compliant

with ICAO Doc 9705 (Edition 2), Sub-volume IV, Section 4.3.

(b) The ATN End System of the data link system should support an ATN Association Control Service Element (ACSE) compliant with ICAO Doc 9705 (Edition 2), Sub-volume IV, Section 4.6.

[Issue: CS-ACNS/5]

GM1 ACNS.B.DLS.120 Application Layer Requirements From an OSI perspective, the ATN Application Layer is composed of three distinct parts:

— Layer 7a, which includes all application-independent services (Control Function + ACSE).

— Layer 7b, which includes all application-dependent service elements (such as the CPDLC-ASE).

— Layer 7c, which includes applications (such as the CPDLC application, which uses CPDLC-ASE for its communications with ground-based systems).

[Issue: CS-ACNS/5]

CS ACNS.B.DLS.125 Database (See GM1 ACNS.B.DLS.125)

The Network Service Access Point (NSAP) address database is capable of being updated.

[Issue: CS-ACNS/5]

GM1 ACNS.B.DLS.125 Database

The Network Service Access Point (NSAP) address database is subject to regular update in accordance with ICAO EUR Doc 028.

[CS-ACNS/5]

APPENDICES

Appendix A — Background information on voice communication systems (a) General

CS-ACNS Issue 5 Subpart B — Communications (COM)

Section 2 — Data Link Services (DLS)

Annex to EDD 2024/003/R Page 59 of 270

This appendix provides additional references, background information, and guidance for maintenance testing, as appropriate to Voice Communication System installations.

(b) Related References

(1) EASA

i. ETSO-2C37e, VHF Radio Communication Transmitting Equipment Operating Within the Radio Frequency Range 117.975–137 Megahertz

ii. ETSO-2C38e,VHF Radio Communication Receiving Equipment Operating Within the Radio Frequency Range 117.975–137 Megahertz

iii. ETSO-2C169a VHF Radio Communications Transceiver Equipment Operating Within the Radio Frequency Range 117.975 To 137 Megahertz.

(2) ICAO

ICAO Annex 10, Volume III, Part II, Voice Communication Systems, Chapter 2 Aeronautical Mobile Service — Second Edition including amendment 85.

(3) EUROCAE

ED-23C June 2009 MOPS for airborne VHF Receiver-Transmitter operating in the frequency range 117.975 – 137.000 MHz.

[Issue: CS-ACNS/4]

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 60 of 270

SUBPART C — NAVIGATION (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

SUBSECTION 1 – APPLICABILITY – GENERAL

CS ACNS.C.PBN.101 Applicability (See AMC1 ACNS.C.PBN.101, GM1 ACNS.C.PBN.101 and GM2 ACNS.C.PBN.101)

(a) Table 1 indicates the applicable airworthiness requirements to be met by the airborne RNP system installation in order to obtain airworthiness approval for the RNP specifications addressed in this CS. Applicants should select the target PBN specification from the left column and then follow the respective row to the right.

(b) Subsection 2 provides also certification criteria for RNAV 10, RNAV 5, RNAV 2 and RNAV 1.

(c) The RNP 0.3 specification is applicable to helicopters.

Table 1: PBN specifications — Mandatory and optional airworthiness requirements

Basic criteria

Supplementary criteria

PBN specification

Subsection s 1 & 2 LNAV

Subsection 3 LNAV in final approach

Subsectio n 4 VNAV

Subsection 5 VNAV in final approach

Subsection 6 RNP AR

Subsection 7 Advanced- RNP

Subsectio n 8 RF

Subsectio n 9 FRT

Subsection 10 Parallel offset

RNP 4 Required Optional Required

RNP 2 Required Optional Optional

RNP 1 Required Optional Optional

RNP 0.3 Required Optional Optional

RNP APCH Required Required Optional Required Optional

RNP AR Required Required Required Required Required Required

A-RNP Required Required Optional Required Required Required Optional Required

Subsection 1: General applicability for performance-based lateral navigation

Subsection 2: Generic specifications for performance-based lateral navigation

Subsection 3: Supplementary specifications for lateral navigation in final approach

Subsection 4: Supplementary specifications for vertical navigation

Subsection 5: Supplementary specifications for vertical navigation in final approach

Subsection 5 includes criteria for RNP APCH approaches to LNAV/VNAV minima, either supported by barometric VNAV or by SBAS VNAV, as well as for RNP APCH approaches to LPV minima, which are supported by SBAS VNAV only. An applicant may opt to apply for

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 61 of 270

approval of the RNP system to conduct operations to LNAV/VNAV minima, LPV minima or both.

Subsection 6: Supplementary specifications for RNP authorisation required (AR)

Subsection 6 includes criteria for RNP AR APCH and RNP AR departures. An applicant may opt to only apply for approval for RNP AR APCH.

Subsection 7: Supplementary specifications for applications for advanced RNP (A-RNP)

Subsection 8: Supplementary specifications supporting radius to fix (RF)

Subsection 9: Supplementary specifications supporting fixed radius transition (FRT)

Subsection 10: Supplementary specifications supporting parallel offset

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.101 Applicability RNAV certification is granted as follows:

(a) Aircraft that comply with the requirements of Subsection 2 comply with all the criteria of the RNAV 1, RNAV 2, and RNAV 5 specifications.

(b) Aircraft equipped with dual multi-sensor RNP systems which integrate inertial position source(s) that meet the criteria of Appendix B and which conform to the requirements of Subsection 2 comply with the criteria of the RNAV 10 specification.

(c) Aircraft that are equipped with dual stand-alone RNP systems with integrated GNSS sensors that comply with the requirements of Subsection 2, comply with the criteria of the RNAV 10 specification if the AFM (or equivalent) contains a requirement stating that:

— an approved fault detection and exclusion (FDE) availability-prediction program is used, and;

— the maximum allowable time for which FDE capability is projected to be unavailable is 34 minutes for any one occasion.

[Issue: CS-ACNS/2]

GM1 ACNS.C.PBN.101 Applicability Subpart C of CS-ACNS provides certification criteria for performance-based navigation. EASA has considered the current and future aircraft equipment and has assumed that most, if not all, aircraft are equipped with one or more GNSS receivers. Subpart C, therefore, considers GNSS equipped aircraft and focuses on compliance with RNP navigation specifications. Compliance with Subsection 2, however, also assures compliance with the RNAV 10, RNAV 5, RNAV 2, and RNAV 1 navigation specifications.

Where the term ‘Required’ is used in Table 1, it refers to compliance with the navigation specification.

It should be noted that for multi-sensor RNP systems, loss of RNP capability does not imply loss of RNAV capability if an inertial or DME navigation source(s) is(are) still operable.

It should be noted that this Subpart does not address communication and surveillance considerations that are, in some cases, related to the implementation of a navigation specification (e.g. controller- pilot data link communications (CPDLC) and automatic dependent surveillance — contract (ADS-C) for RNP 4) within a particular airspace.

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 62 of 270

The ICAO PBN Manual (Doc 9613) contains 11 navigation specifications, each of them addressing specific operations by flight phase:

(a) RNAV 10, historically referred to as RNP 10, is applied for oceanic and remote continental navigation operations;

(b) RNAV 5, RNAV 2 and RNAV 1 are applied for continental en-route and terminal navigation operations;

(c) RNP 4 and RNP 2 and A-RNP are applied for oceanic and remote continental navigation operations;

(d) RNP 2 and A-RNP are applied for continental en-route navigation operations;

(e) RNP 1 and A-RNP are applied for terminal navigation operations;

(f) A-RNP, RNP APCH, and RNP AR APCH are applied for initial, intermediate, final, and missed approach navigation operations, and may include requirements for vertical navigation (VNAV);

(g) RNP 0.3 was specifically written to facilitate (low-level) en-route operations with rotorcraft.

Subpart C on performance-based navigation contains basic and supplemental certification criteria. The basic criteria must always be complied with, regardless of the navigation specification, and ensure compliance with the navigational requirements of the RNAV 10, RNAV 5, RNAV 2, RNAV 1, RNP 2, RNP 1 and RNP 0.3 criteria.

Some navigation specifications require compliance with supplemental criteria, e.g. compliance with Subsection 10 for parallel offsets for RNP 4.

The criteria for navigation specifications that include approach, i.e. A-RNP, RNP APCH and RNP AR, are more specific. Subsection 3 (‘LNAV in final approach’) and Subsection 5 (‘VNAV in final approach’) apply to these operations. In addition, both RNP AR and A-RNP have their own specific criteria that need to be met, as described in Subsection 6 for RNP AR and Subsection 7 for A-RNP.

Subsection 4 addresses vertical navigation (VNAV) outside the final approach part of the flight. It contains criteria for compliance with altitude constraints considered in Commission Implementing Regulation (EU) 2018/1048.

In addition to the criteria for RNP APCH approaches, Subsection 5 also contains optional requirements for advisory VNAV, which apply to the final approach segment (FAS) only.

Subsections 8, 9, and 10 contain criteria for specific functions. These functions (radius to fix, fixed radius transition, and parallel offset) are required for some applications and are optional for some others.

In some instances, the CS requirements deviate from the ICAO navigation specification, for example by requiring VNAV for RNP APCH. This is based on recent certification experience, the fact that CS- ACNS is a forward-looking document that is based on the latest ICAO and industry standards, and it is also a consequence of the way Section 1 has been structured. Where applicants intent to strictly apply the criteria of the ICAO navigation specification, they are invited to consult EASA (e.g. an applicant applying for RNP APCH without VNAV down to LNAV minima or LP minima only).

Applicants intending to apply strictly for RNAV navigation specifications predicated on conventional ground navigation aids, i.e. non-GNSS-based navigation, are also invited to consult EASA.

Example application of Table 1:

Question: An applicant wishes to apply for certification of an aircraft for RNP APCH. Which subsections of Subpart C should the applicant demonstrate compliance with?

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 63 of 270

Answer: Subsections 1 and 2, and the supplemental and the more stringent criteria provided in Subsections 3 and 5 for lateral and vertical navigation, respectively. The applicant may need to also demonstrate compliance with Subsection 8, which is optional, as the RF functionality could be used in the initial and intermediate approach segments, and in the final phase of the missed approach.

Additionally, Appendix C to Subpart C provides guidance material for the installation of equipment constituting the aircraft’s RNP system and for testing the aircraft’s RNP system.

[Issue: CS-ACNS/2]

GM2 ACNS.C.PBN.101 Applicability With the publication of CS-ACNS, AMC 20-4A, AMC 20-5, AMC 20-12, AMC 20-26, AMC 20-27A, AMC 20-28, JAA TGL-10 and CM-AS-002 Issue 2 have become obsolete. This, however, does not invalidate existing approvals to these references.

Changes to aircraft/systems that were approved to the above AMC-20 references or TGL will be handled as follows:

— Where the change remains within the original scope of the AMC or TGL, i.e. no new functionality is added, the applicant may continue to use the criteria of the AMC or TGL as the certification basis for the change.

— Where the change is outside the original scope of the AMC or TGL, i.e. a new functionality is added, the corresponding certification criteria in CS-ACNS are to be applied. Given the differences in the set-up of the AMC/TGL compared to CS-ACNS, an applicant may, within reason, claim credit for items already demonstrated to an AMC or TGL that are similar to the requirements in CS-ACNS.

Examples:

1) An aircraft has been approved to perform RNP AR operations to the criteria of AMC 20-26. The applicant is updating the software of the flight management system, but no additional functionality is being added. In that case, the criteria of AMC 20-26 continue to be applicable.

2) An aircraft has been approved to conduct RNP APCH operations to LNAV or LNAV/VNAV using barometric VNAV in accordance with AMC 20-27A. The applicant is replacing the GNSS receiver with one that can receive differential correction signals from a satellite based augmentation system (SBAS) and adds the capability to operate on RNP APCH approach procedures to LP or LPV minima. This capability was not within the original scope of AMC 20-27A. The applicant should, therefore, apply the criteria of the new CS-ACNS. Credit may be claimed for items already demonstrated as part of the compliance demonstration to AMC 20-27A, where these may be considered to be reasonably similar and applicable.

[Issue: CS-ACNS/2]

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 64 of 270

SUBSECTION 2 – GENERIC SPECIFICATIONS FOR PERFORMANCE-BASED LATERAL

NAVIGATION

APPLICABILITY

CS ACNS.C.PBN.201 Applicability Subsection 2 provides the functional and performance criteria that are common to all PBN specifications for lateral navigation.

[Issue: CS-ACNS/2]

SYSTEM QUALIFICATION CRITERIA

CS ACNS.C.PBN.205 RNP system approval (See AMC1 ACNS.C.PBN.205, AMC2 ACNS.C.PBN.205, GM1 ACNS.C.PBN.205, GM2 ACNS.C.PBN.205 and GM3 ACNS.C.PBN.205)

All equipment contributing to the area navigation function is approved.

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.205 RNP system approval For all navigation specifications except RNP 0.3:

(a) where the RNP system architecture is based on a stand-alone system, the RNP system should be granted a European Technical Standard Order (ETSO) authorisation against the following ETSO:

(1) ETSO-C146c (operational Class 3).

(2) ETSO-C190 active antenna.

(b) where the RNP system architecture is based on a flight management system (FMS) receiving input from various sources of position, the FMS should be granted an ETSO authorisation against ETSO-C115d and, depending on the type of sources to determine position, these should be granted an ETSO authorisation against the following ETSO or be compliant with the following standards:

(1) GNSS position source against ETSO-C196a or ETSO-C145c (operational Class 3);

(2) GNSS antenna against:

(i) ETSO-C144a passive antenna when an ETSO-C196a GNSS position source is installed, or;

(ii) ETSO-C190 active antenna when an ETSO-C196a or ETSO-C145c GNSS position source is installed.

(3) DME/DME horizontal position source based on a DME interrogator that has been granted an ETSO authorisation against ETSO-2C66b;

(4) barometric altimeter: ETSO-C106 Amendment 1.

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 65 of 270

(c) with reference to CS ACNS.A.GEN.020, any deviations from the ETSOs should be evaluated against the relevant sections of EUROCAE ED-75D Minimum Aviation System Performance Standard (MASPS).

(d) noting that there is no equipment standard for INS/IRU horizontal position source, this equipment should comply with the functionality and performance that is detailed in Appendix B.

[Issue: CS-ACNS/2]

AMC2 ACNS.C.PBN.205 RNP system approval For compliance with the RNP 0.3 navigation specification, the RNP system is supported by an SBAS capable GNSS position source, i.e. one that has been authorised against ETSO-C145c (operational Class 3) or ETSO-C146c (operational Class 3).

[Issue: CS-ACNS/2]

AMC3 ACNS.C.PBN.205 RNP system approval Where AMC to Section 1 of Subpart C contain a reference to the criteria of EUROCAE Document ED- 75D, these criteria are considered to be means to comply with the related CSs. Therefore, these criteria may be applied instead of installing ETSO-authorised equipment.

Where AMC to Section 1 of Subpart C contain a reference to a specific amendment to an ETSO, it indicates the minimum acceptable standard, so any subsequent amendments are also considered to be acceptable.

[Issue: CS-ACNS/2]

GM1 ACNS.C.PBN.205 RNP system approval Subpart C of CS-ACNS is based on EUROCAE ED-75D (RTCA DO-236C and Change 1), except for RNP AR, and on the ICAO PBN Manual (Doc 9613).

The AMC to Subpart C requirements encourage the installation of ETSO-authorised equipment, recognising the fact that many of the EUROCAE ED-75D requirements are covered through compliance with ETSO requirements. Recognition of ETSO authorisation generally limits the burden on the applicant that demonstrates compliance with the CS requirements.

[Issue: CS-ACNS/2]

GM2 ACNS.C.PBN.205 RNP system approval ETSO-C145c and ETSO-C146c (operational Class 3) support the following operations:

(a) oceanic/remote en route;

(b) continental en route;

(c) arrival;

(d) approach down to LNAV minima;

(e) approach down to LNAV/VNAV minima;

(f) approach down to LP minima;

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 66 of 270

(g) approach down to LPV minima; and

(h) departure;

ETSO-C146c (functional Class D, operational Class 4) only supports approach down to LP and LPV minima and is, therefore, only recognised as AMC for lateral navigation in final approach (see AMC1 ACNS.C.PBN.305).

The minimum system requirements may also depend on the intended airspace to be flown; hence, carriage of additional navigation systems could be required.

[Issue: CS-ACNS/2]

GM3 ACNS.C.PBN.205 RNP system approval Integrated GNSS/INS position solutions reduce the rate of degradation after loss of position updating. For ‘tightly coupled’ GNSS/IRUs, RTCA Document DO-229D, Appendix R, and RTCA Document DO-316, Appendix R, provide additional guidance on ‘tightly coupled’ GNSS/IRUs.

[Issue: CS-ACNS/2]

CS ACNS.C.PBN.210 Position source (See AMC1 ACNS.C.PBN.210 )

The RNP system uses GNSS as the primary source of horizontal position.

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.210 Position source If other horizontal position sources are available, they may be used to complement the GNSS- computed position, provided that the output position continues to meet the required performance.

If the position is no longer available from a GNSS position source and if additional sources are available, the system should revert to the best available source (e.g. the source that can provide the best computed position in terms of accuracy and integrity).

Installation of equipment with an ETSO authorisation against ETSO-C115d satisfies the requirement.

[Reference: ED-75D § 3.7.3.1.2]

[Issue: CS-ACNS/2]

FUNCTIONAL CRITERIA

RNP system

CS ACNS.C.PBN.215 Position estimation (See AMC1 ACNS.C.PBN.215 and GM1 ACNS.C.PBN.215)

The RNP system continuously estimates:

(a) the present lateral position of the aircraft; and

(b) the accuracy and integrity of the lateral position, when supported by the navigation sensors.

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 67 of 270

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.215 Position estimation Installation of equipment with an ETSO authorisation against ETSO-C115d or ETSO-C146c (operational Class 3) satisfies the requirement.

[Reference: ED-75D § 3.1.1.1]

[Issue: CS-ACNS/2]

GM1 ACNS.C.PBN.215 Position estimation The estimated lateral position accuracy is a measure that is based on a defined scale, in nautical miles, which conveys the current position estimation performance. The lateral position accuracy can be related to the required navigation performance (RNP) value.

[Issue: CS-ACNS/2]

CS ACNS.C.PBN.220 Navigation source selection and reversion (See AMC1 ACNS.C.PBN.220)

When a multi-sensor RNP system is installed, it has the capability to automatically, or manually, select the best available navigation source(s).

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.220 Navigation source selection and reversion Installation of equipment with an ETSO authorisation against ETSO-C115d satisfies the requirement.

[Reference: ED-75D § 3.7.3.1]

[Issue: CS-ACNS/2]

CS ACNS.C.PBN.225 Reasonableness check of distance-measuring equipment (DME) (See AMC1 ACNS.C.PBN.225)

When the RNP system uses DME, it has the capability to perform a reasonableness check of the radio navigation data.

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.225 Reasonableness check of distance- measuring equipment (DME) Installation of equipment with an ETSO authorisation against ETSO-C115d satisfies the requirement.

[Reference: ED-75D § 3.7.3.1.1]

[Issue: CS-ACNS/2]

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 68 of 270

CS ACNS.C.PBN.230 Flight plan management (See AMC1 ACNS.C.PBN.230)

The RNP system provides flight crew with the capability to create, review, modify and activate a flight plan. Activation of any new flight plan or modification of an existing flight plan requires a positive action by the flight crew. Guidance output is not affected until the flight plan or its modification is activated. Once the plight plan is activated, the RNP system has the capacity to execute it.

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.230 Flight plan management (a) The RNP system should be capable of displaying:

(1) the along-track distance between any flight plan waypoints;

(2) the distance to go to any waypoint selected by the flight crew; and

(3) the actual waypoint and the data that defines it.

(b) The RNP system should enable modification of any flight plan, or flight plan segment, including procedures that were loaded from the on-board navigation database. However, FAS data blocks protected by a cyclic redundancy check (CRC) code can never be modified.

(c) The RNP system should allow the creation and insertion of pilot-defined fixes and related data.

Installation of equipment with an ETSO authorisation against ETSO-C115d is considered to meet the criteria of (b), and (c). It also supports item (a); however, the applicant should ensure the flight deck interface complies with this CS.

Installation of equipment with an ETSO authorisation against ETSO-C146c (operational Class 3) is considered to meet the criteria of (a) through (d).

[Reference: ED-75D § 3.7.2.1.1.1]

[Issue: CS-ACNS/2]

CS ACNS.C.PBN.235 Automatic leg sequencing (See AMC1 ACNS.C.PBN.235 )

The RNP system has the capability to automatically sequence legs and display the sequencing to the flight crew in a readily visible manner.

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.235 Automatic leg sequencing Installation of equipment with an ETSO authorisation against ETSO-C115d and ETSO-C146c satisfies the requirement.

[Reference: ED-75D § 3.7.2.1.4]

[Issue: CS-ACNS/2]

CS ACNS.C.PBN.240 Route/procedure extraction and loading (See AMC1 ACNS.C.PBN.240)

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 69 of 270

The RNP system has the capability to extract routes/procedures from the on-board navigation database in their entirety, including all their characteristics, and to load them into the RNP system’s flight plan.

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.240 Route/procedure extraction and loading Installation of equipment with an ETSO authorisation against ETSO-C115d satisfies the requirement.

The installation of equipment with an ETSO authorisation against ETSO-C146c satisfies the CS requirement, provided that the applicant ensures that speed constraints are extracted from the database.

[Reference: ED-75D § 3.7.2.1.1.1]

[Issue: CS-ACNS/2]

CS ACNS.C.PBN.245 Path definition and leg transition (See AMC1 ACNS.C.PBN.245 and GM1 ACNS.C.PBN.245)

(a) The RNP system allows flight crew to define the flight path for the intended route.

(b) The RNP system has the capability to execute leg transitions and maintain tracks consistent with the following path terminators:

(1) direct to fix (DF), track to a fix (TF), initial fix (IF), fix to an altitude (FA), and course to a fix (CF);

(2) heading to an altitude (VA), heading to a manual termination (VM), and heading to an intercept (VI);

(3) course to an altitude (CA), and from a fix to a manual termination (FM).

(c) The RNP system has the capability to execute fly-by turns.

(d) Unless otherwise specified in the on-board navigation database, the RNP system constructs the flight path between waypoints in the same manner as a TF leg.

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.245 Path definition and leg transition Installation of equipment with an ETSO authorisation against ETSO-C115d satisfies the requirements.

Installation of equipment with an ETSO authorisation against ETSO-C146e satisfies the requirements.

Installation of equipment with an ETSO authorisation against ETSO-C146c satisfies the requirements of (a), (b)(1), (c) and (d).

Subject to EASA’s agreement, where the RNP system does not support the execution of VA, VM, and VI path terminators, the applicant may demonstrate that the aircraft and flight systems allow the flight crew to manually fly the aircraft on a heading to intercept a course or to go direct to another fix after reaching a procedure-specified altitude. The manual execution of VA, VM and VI terminators should be supported by a flight crew workload assessment.

Subject to EASA’s agreement, where the RNP system does not support the execution of CA and FM path terminators, the applicant may demonstrate that the RNP system allows the flight crew to readily

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 70 of 270

designate a waypoint and select a desired course to or from a designated waypoint. The manual execution of CA and FM terminators should be supported by a flight crew workload assessment.

[References: ED-75D § 3.2.1.2 and ED-75D § 3.2.5.4]

[Issue: CS-ACNS/2]

GM1 ACNS.C.PBN.245 Path definition and leg transition (a) The intent of CS ACNS.C.PBN.245(d) is to ensure a smooth transition.

(b) Path terminators and leg transitions are defined in Aeronautical Radio, Inc. (ARINC) 424 documents, and their application is described in more detail in EUROCAE ED-75D, and ED-77 (RTCA documents DO-236C Change 1, and DO-201A).

[Issue: CS-ACNS/2]

CS ACNS.C.PBN.250 ‘Direct-to’ function (See AMC1 ACNS.C.PBN.250)

The RNP system has the capability to generate and execute a geodesic path to any designated fix, at any time, without ‘S-turning’ and without undue delay, known as ‘direct-to’ function.

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.250 ‘Direct-to’ function Installation of equipment with an ETSO authorisation against ETSO-C115d or ETSO-C146c satisfies the requirement.

[Reference: ED-75D § 3.2.4.2]

[Issue: CS-ACNS/2]

CS ACNS.C.PBN.255 Magnetic variation (See AMC1 ACNS.C.PBN.255)

(a) The required navigation performance (RNP) system has the capability to assign a magnetic variation at any location within the region where flight operations are conducted, using the magnetic north as reference.

(b) For paths defined by a course, the RNP system uses the appropriate magnetic variation value available in the navigation database.

(c) The conditions under which the magnetic variation table (MAGVAR table), certified as part of the aircraft configuration, is updated are included in the aircraft’s instructions for continued airworthiness (ICAs).

[Issue: CS-ACNS/2]

[Issue: CS-ACNS/4]

AMC1 ACNS.C.PBN.255 Magnetic variation Installation of equipment with an ETSO authorisation against ETSO-C115d or ETSO-C146c satisfies the requirement of (a) and (b).

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 71 of 270

[Reference: ED-75D § 3.2.5.2]

[Issue: CS-ACNS/2]

CS ACNS.C.PBN.260 RNAV holding (See AMC1 ACNS.C.PBN.260 and GM1 ACNS.C.PBN.260)

(a) The RNP system has the capability to initiate, maintain and discontinue holding procedures at any point and at all altitudes. When a holding procedure is initiated, the RNP system:

(1) permits the flight crew to readily select a desired course to the holding waypoint;

(2) retains all subsequent waypoints in the active flight plan in the same sequence; and

(3) permits the flight crew to readily initiate the return to automatic waypoint sequencing at any time and continue with the existing flight plan.

(b) The RNP system allows for manual or automatic definition of the holding pattern.

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.260 RNAV holding Installation of equipment with an ETSO authorisation against ETSO-C115d satisfies the requirement, provided that the equipment meets the criteria defined in RTCA DO-283B § 2.2.1.2.6.

Installation of equipment with an ETSO authorisation against ETSO-C146c satisfies the requirement.

[Reference: ED-75D § 3.7.2.2.3.1]

[Issue: CS-ACNS/2]

GM1 ACNS.C.PBN.260 RNAV holding The intent of the CS is to require RNAV holding, not RNP holding.

[Issue: CS-ACNS/2]

CS ACNS.C.PBN.265 User-defined routes and fixes (See AMC1 ACNS.C.PBN.265 and GM1 ACNS.C.PBN.265)

The RNP system provides means for the flight crew to build a user-defined route by:

(a) entering unique waypoints extracted from the on-board navigation database; and

(b) manually creating user-defined fixes.

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.265 User-defined routes and fixes Installation of equipment with an ETSO authorisation against ETSO-C115d or ETSO-C146c satisfies the requirement.

[References: ED-75D § 3.7.2.1.2.1 & ED-75D § 3.7.2.1.2.2]

[Issue: CS-ACNS/2]

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 72 of 270

GM1 ACNS.C.PBN.265 User-defined routes and fixes User-defined fixes are usually defined via the entry of latitude/longitude, place/along-track, place/bearing-place/bearing, and place/bearing/distance.

[Issue: CS-ACNS/2]

CS ACNS.C.PBN.270 Navigation accuracy (See AMC1 ACNS.C.PBN.270)

(a) The RNP system is capable of acquiring and setting the RNP value for each segment of a route or procedure.

(b) When an aircraft flies an RNP route or procedure and the RNP value changes to a lower value, the RNP completes the change no later than reaching the leg with the lower RNP value.

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.270 Navigation accuracy (a) The RNP value associated with a leg or segment should be assigned in the following order of

precedence:

(1) flight crew manually entered RNP value for the leg or segment;

(2) the RNP value coded in the on-board navigation database for the current leg or segment, if implemented;

(3) the RNP value coded in the on-board navigation database for the current area, if implemented; and last

(4) a system default RNP value, if provided by the RNP system.

(b) Installation of equipment with an ETSO authorisation against ETSO-C115d or ETSO-C146c satisfies the requirement.

[References: ED-75D § 3.7.2.1.3.1, ED-75D § 3.2.6, ED-75D § 3.2.6.2]

[Issue: CS-ACNS/2]

Display of navigation data

CS ACNS.C.PBN.275 Display and entry of navigation data — resolution (See AMC1 ACNS.C.PBN.275)

The RNP system displays and allows manual entry of navigation data with a resolution that supports the intended operation.

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.275 Display and entry of navigation data — resolution Installation of equipment with an ETSO authorisation against ETSO-C115d or ETSO-C146c satisfies the requirement.

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 73 of 270

[Reference: ED-75D § 3.6.2]

[Issue: CS-ACNS/2]

CS ACNS.C.PBN.280 Deviation display (See AMC1 ACNS.C.PBN.280, AMC2 ACNS.C.PBN.280 and AMC3 ACNS.C.PBN.280)

(a) For defined paths, the RNP system continuously displays, in each flight crew’s optimum field of view, the computed path and the deviation from that path.

(b) The lateral deviation display is automatically slaved to the RNP system’s computed path.

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.280 Deviation display An acceptable means of compliance is to provide a non-numeric deviation display. The full-scale deflection of the non-numeric lateral deviation display should be:

(a) comparable with the applicable RNP value; and

(b) made available to the flight crew.

Alternatively, subject to EASA’s agreement, a moving map display with appropriate map scales, and which provides a sufficiently equivalent functionality to a non-numeric lateral deviation display, may be accepted. EASA’s agreement will be based on a human factor and workload assessment performed by the applicant.

[Issue: CS-ACNS/2]

AMC2 ACNS.C.PBN.280 Deviation display When used to conduct a departure procedure off the runway, the RNP system should display lateral deviations not later than when reaching 50 feet above the departure runway. Installation of equipment with an ETSO authorisation against ETSO-C115d or ETSO-C146c supports this.

[Reference: ED-75D § 3.3.3.1]

[Issue: CS-ACNS/2]

AMC3 ACNS.C.PBN.280 Deviation display Subject to EASA’s agreement, a lateral deviation display not slaved to the RNP system associated with adequate operational procedures may be accepted for type-certification application against RNP 2, RNP 1 or RNP APCH. The applicant should provide a human factor and workload assessment in support of the application.

Note: The alleviation provided above is intended to address particular concerns on small CS-23, Level 1, 2, and 3 aircraft.

[Issue: CS-ACNS/2]

CS ACNS.C.PBN.285 Display of active waypoint (See AMC1 ACNS.C.PBN.285 and AMC2 ACNS.C.PBN.285)

The RNP system displays in the flight crew’s maximum field of view:

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 74 of 270

(a) the identification of the active (To) waypoint; and

(b) the distance, estimated time of arrival at, or time-to go to, and bearing to the active (To) waypoint.

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.285 Display of active waypoint The installation of equipment with an ETSO authorisation against ETSO-C146c satisfies the CS requirement, provided that the applicant ensures that both the distance to and the estimated time of arrival at the active waypoint are available to the flight crew.

[Issue: CS-ACNS/2]

AMC2 ACNS.C.PBN.285 Display of active waypoint Subject to EASA’s agreement, the display of the data on a page on a multifunction control and display unit (MCDU), readily accessible to the flight crew, may be accepted for type-certification application against RNP 4 or RNP 2. EASA’s agreement will be based on a human factor and workload assessment performed by the applicant.

[Issue: CS-ACNS/2]

CS ACNS.C.PBN.290 Display of ground speed (See AMC1 ACNS.C.PBN.290)

The RNP system displays the ground speed in the flight crew’s maximum field of view.

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.290 Display of ground speed The installation of equipment in the flight crew’s maximum field of view with an ETSO authorisation against ETSO-C146c satisfies the requirement.

Installation of equipment with an ETSO authorisation against ETSO-C115d supports the requirement, provided that the applicant ensures that the flight deck interface complies with this CS.

[Reference: ED-75D § 3.7.5.2.1]

[Issue: CS-ACNS/2]

CS ACNS.C.PBN.2105 Display of speed constraints (See AMC1 ACNS.C.PBN.2105)

The RNP system displays speed constraints to the flight crew in the maximum field of view.

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.2105 Display of speed constraints Subject to EASA’s agreement, a display of speed constraints outside the maximum field of view with adequate operational procedures may be accepted. The applicant should provide a human factor and workload assessment in support of the application.

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 75 of 270

[Issue: CS-ACNS/2]

CS ACNS.C.PBN.2110 Display of navigation aid frequencies and/or identifiers The RNP system has the capability to display the frequencies and/or identifiers of the ground positioning navigation aids selected on a page which is readily available to the flight crew.

[Issue: CS-ACNS/2]

Navigation database

CS ACNS.C.PBN.2115 Use of navigation database (See AMC1 ACNS.C.PBN.2115 and GM1 ACNS.C.PBN.2115)

The RNP system uses an on-board navigation database which:

(a) is protected against flight crew modification of the stored data; and

(b) has a capacity appropriate for the intended operation.

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.2115 Use of navigation database The installation of equipment with an ETSO authorisation against ETSO-C115d or ETSO-C146C satisfies the CS requirement, provided that the applicant ensures that the database capacity is appropriate for the intended operation.

[References: ED-75D § 3.8.1, ED -75D § 3.8.2]

[Issue: CS-ACNS/2]

GM1 ACNS.C.PBN.2115 Use of navigation database The storage capacity is consistent with the intended use of the aircraft. For example, the database of a regional aircraft may contain data for a given region only, whereas the database of a long-range aircraft may contain worldwide data.

[Issue: CS-ACNS/2]

CS ACNS.C.PBN.2120 Data quality requirements (DQRs) (See AMC1 ACNS.C.PBN.2120)

The applicant ensures that the DQRs associated with the navigation database have been defined and are compatible with the intended function through formal arrangements that are signed with the corresponding data services provider(s) (DAT provider).

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.2120 Data quality requirements (DQRs) Since database process assurance levels are normally addressed at equipment design level, the applicant should verify with the equipment manufacturer that the DQRs have been established and

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 76 of 270

provided to the navigation database provider(s). Formal arrangements should also ensure that deficiencies and/or errors detected by the DAT provider can be reported to the applicant, whenever DQRs could be compromised.

Documentation that these data quality requirements are valid at aircraft level must be confirmed during the airworthiness approval.

[Issue: CS-ACNS/2]

CS ACNS.C.PBN.2125 Extraction and display of navigation data (See AMC1 ACNS.C.PBN.2125 and GM1 ACNS.C.PBN.2125)

The RNP system has the means to:

(a) process the data with the resolution provided by the database; and

(b) enable flight crew to:

(1) verify the validity period of the on-board navigation database; and

(2) load from the on-board navigation database, by its identifier(s), the procedure(s) to be flown.

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.2125 Extraction and display of navigation data The installation of equipment with an ETSO authorisation against ETSO-C115d or ETSO-C146c satisfies the requirement.

[Reference: ED-75D § 3.8.2]

[Issue: CS-ACNS/2]

GM1 ACNS.C.PBN.2125 Extraction and display of navigation data The intent of CS ACNS.C.PBN.2125(a) is not to prevent truncating resolution to optimise performance as long as the truncation is commensurate with the procedure. Rather, the intent is to ensure compatibility between the database and the RNP system.

[Issue: CS-ACNS/2]

Monitoring and alerting

CS ACNS.C.PBN.2130 Alerting associated with degradation of navigation (See AMC1 ACNS.C.PBN.2130)

When the RNP system is unable to meet the RNP value, the RNP system provides, without undue delay, an indication in the flight crew’s optimum field of view.

[Issue: CS-ACNS/2]

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 77 of 270

AMC1 ACNS.C.PBN.2130 Alerting associated with degradation of navigation The alerting requirement is satisfied by installation of equipment with an ETSO authorisation against ETSO-C115d or ETSO-C146c, provided that the applicant ensures that the alert is appropriately indicated in the flight crew’s optimum field of view, and assess any processing delays caused by the aircraft flight deck alerting system.

Subject to EASA’s agreement, display of the alert in the flight crew’s maximum field of view may be accepted. The applicant should support the deviation by providing a human factor and workload assessment.

Note: The alleviation provided above is intended to address particular concerns on smaller aircraft, for example, CS-23, Level 1, 2, and 3 aircraft.

[Reference: ED-75D § 3.7.6]

[Issue: CS-ACNS/2]

CS ACNS.C.PBN.2135 Navigation accuracy alerting (See AMC1 ACNS.C.PBN.2135)

The RNP system provides an annunciation if a manually entered RNP value is greater than the RNP value associated with the current routes and procedures as defined in the on-board navigation database. Any subsequent reduction of the latter RNP value reinstates this annunciation.

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.2135 Navigation accuracy alerting Installation of equipment with an ETSO authorisation against ETSO-C115d satisfies the CS criteria, provided that the applicant ensures that the flight deck interface complies with the CS.

This CS is typically not relevant for equipment with an ETSO authorisation against ETSO-C146c. If this equipment provides a facility to the flight crew to enter the RNP value, then this alerting mechanism should be implemented as well.

Note: This functionality is not part of the functionalities specified in RTCA Document DO-229D (MOPS).

[Reference: ED-75D § 3.7.6.1]

[Issue: CS-ACNS/2]

PERFORMANCE CRITERIA

Lateral performance

CS ACNS.C.PBN.2140 Lateral navigation accuracy (See AMC1 ACNS.C.PBN.2140)

The lateral navigation accuracy provided by the RNP system supports the intended operations.

[Issue: CS-ACNS/2]

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 78 of 270

AMC1 ACNS.C.PBN.2140 Lateral navigation accuracy Installation of equipment with an ETSO authorisation against ETSO-C115d and ETSO-C146c satisfies the requirement.

[References ED-75D §1.7.1, §1.7.2 and §2.1.1]

[Issue: CS-ACNS/2]

CS ACNS.C.PBN.2145 RNP system design — integrity (See AMC1 ACNS.C.PBN.2145)

The RNP system, including position sensors, displays, etc., is designed to provide a level of integrity that supports the intended operation.

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.2145 RNP system design — integrity Guidance on the integrity (provisioning of erroneous output or display of data) of the RNP system related to lateral position or guidance is provided in Appendix A to Subpart C.

[Issue: CS-ACNS/2]

CS ACNS.C.PBN.2150 RNP system design — continuity (See AMC1 ACNS.C.PBN.2150)

The RNP system, including position sensors, displays, etc., is designed to provide a level of continuity that supports the intended operation.

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.2150 RNP system design — continuity Guidance on the continuity (loss of the function) of the RNP system to provide lateral position or guidance is provided in Appendix A to Subpart C.

[Issue: CS-ACNS/2]

SUBSECTION 3 – SUPPLEMENTARY SPECIFICATIONS FOR LATERAL NAVIGATION IN

FINAL APPROACH

APPLICABILITY

CS ACNS.C.PBN.301 Applicability (See GM1 ACNS.C.PBN.301)

Subsection 3 provides the supplementary functional and performance criteria that are applicable to the lateral navigation function for the final approach segment; these criteria are necessary to obtain certification against the RNP specifications that support approach operations (i.e. A-RNP, RNP APCH and RNP AR APCH).

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 79 of 270

[Issue: CS-ACNS/2]

GM1 ACNS.C.PBN.301 Applicability The lateral navigation capabilities of RNP systems that are required to support initial, intermediate, and missed approach segments of an approach procedure are described in Subsection 2.

[Issue: CS-ACNS/2]

SUPPLEMENTARY FUNCTIONAL CRITERIA

RNP system

CS ACNS.C.PBN.305 RNP system approval (See AMC1 ACNS.C.PBN.305)

All equipment contributing to the area navigation function is approved.

[Issue: CS-ACNS/2]

AMC 1 ACNS.C.PBN.305 RNP system approval In addition to the systems referenced in AMC1 ACNS.C.PBN.205, equipment authorised against ETSO- C146c functional Class Delta (operational Class 4) supports operations to LP and LPV minima.

[Issue: CS-ACNS/2]

CS ACNS.C.PBN.310 Final approach intercept (See AMC1 ACNS.C.PBN.310 and GM1 ACNS.C.PBN.310)

The RNP system has the capability to intercept the final approach course at or before the final approach fix or the final approach point.

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.310 Final approach intercept The installation of equipment with an ETSO authorisation against ETSO-C146c Class 3 or 4 and ETSO- C115d Class A satisfies the requirement.

[Reference: ED-75D § 3.2.8.4]

[Issue: CS-ACNS/2]

GM1 ACNS.C.PBN.310 Final approach intercept The capability to intercept the final approach provides the pilot with the ability to capture the published final approach segment following a period when the aircraft has been flown manually, or in autopilot/automatic flight control system heading mode, following ATC vectors to support final approach sequencing.

[Issue: CS-ACNS/2]

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 80 of 270

Display of navigation data

CS ACNS.C.PBN.320 Approach mode indication (See GM1 ACNS.C.PBN.320)

The RNP system provides unambiguous indications in the flight crew’s maximum field of view that enables the flight crew to readily identify:

(a) the type of approach that is being flown and the applicable line of minima; and

(b) whether the guidance is angular or linear.

[Issue: CS-ACNS/2]

GM1 ACNS.C.PBN.320 Approach mode indication The requirement is intended to avoid confusion with regard to the type of approach procedure that is being flown and the line of minima applicable to that approach procedure, e.g. down to LNAV/VNAV minima. It is not required to actually indicate the value associated with the applicable minima.

[Issue: CS-ACNS/2]

CS ACNS.C.PBN.325 Lateral deviation display (See AMC1 ACNS.C.PBN.325)

The RNP system continuously displays on a non-numeric lateral deviation display, in each flight crew’s optimum field of view, the deviation from the computed path.

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.325 Lateral deviation display The deviation indicators on the non-numerical lateral display should appear in a timely fashion to allow the flight crew to intercept the final approach segment.

[Issue: CS-ACNS/2]

CS ACNS.C.PBN.330 Non-numeric lateral deviation display scaling for approach (See AMC1 ACNS.C.PBN.330)

The full-scale deflection of the non-numeric lateral deviation display supports the applicable track- keeping accuracy that is required for the approach.

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.330 Non-numeric lateral deviation display scaling for approach (a) When linear lateral deviation is provided, the full-scale deflection of the non-numeric deviation

display should not exceed two times the RNP value.

(b) When angular lateral deviation is provided:

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 81 of 270

(1) installation of equipment with an ETSO authorisation against ETSO-C146c operational Class 3 or 4 satisfies the requirement; or

(2) the full-scale deflection of the non-numeric deviation display should allow the aircraft to remain within the two times RNP value of (a) above

[Issue: CS-ACNS/2]

CS ACNS.C.PBN.335 Display of distance to threshold For approaches to LPV minima, the RNP system continuously displays in the flight crew’s maximum field of view the distance to the landing threshold point/fictitious threshold point (LTP/FTP) or missed approach point (MAPt) after passing the final approach fix/final approach point.

[Issue: CS-ACNS/2]

SUBSECTION 4 – SUPPLEMENTARY SPECIFICATIONS FOR VERTICAL NAVIGATION

APPLICABILITY

CS ACNS.C.PBN.401 Applicability (See GM1 ACNS.C.PBN.401)

Subsection 4 provides the supplementary requirements that support the use of vertical navigation outside the final approach segment.

[Issue: CS-ACNS/2]

GM1 ACNS.C.PBN.401 Applicability (See CS ACNS.C.PBN.401)

The criteria of Subsection 4 are based on the PBN Manual, Volume II, Attachment A, and are intended to support the definition of vertical paths in airspace where vertical navigation outside the approach is intended to be applied in environments with high traffic density, traffic complexity, or terrain features, as for example those defined in the Commission Implementing Regulation (EU) 2018/1048.

[Issue: CS-ACNS/2]

SUPPLEMENTARY FUNCTIONAL CRITERIA

RNP system

CS ACNS.C.PBN.405 Vertical path The RNP system has the capability to define a vertical path to a fix.

[Issue: CS-ACNS/2]

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 82 of 270

CS ACNS.C.PBN.410 Altitude constraints (See AMC1 ACNS.C.PBN.410)

Where barometric altimetry is used as the source for vertical guidance (BARO-VNAV), the RNP system has the capability to specify a vertical path between altitude constraints at two fixes in the flight plan.

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.410 Altitude constraints The altitude constraints should be defined as follows:

(a) an ‘AT or ABOVE’ altitude constraint;

(b) an ‘AT or BELOW’ altitude constraint;

(c) an ‘AT’ altitude constraint; or

(d) a ‘WINDOW’ altitude constraint.

The installation of equipment with an ETSO authorisation against ETSO-C115d satisfies the requirement.

[Reference: ED-75D § 3.2.8.1]

[Issue: CS-ACNS/2]

CS ACNS.C.PBN.420 Pressure settings (See GM1 ACNS.C.PBN.420)

Where barometric altimetry is used as the source for vertical guidance (BARO-VNAV), the RNP system uses the same pressure-setting input as the aircraft’s altimetry system.

[Issue: CS-ACNS/2]

GM1 ACNS.C.PBN.420 Pressure settings This requirement is intended to prevent potential flight crew errors due to different altimeter settings in the aircraft altimeter system and RNP system.

[Issue: CS-ACNS/2]

SUBSECTION 5 – SUPPLEMENTARY SPECIFICATIONS FOR VERTICAL NAVIGATION IN

FINAL APPROACH

APPLICABILITY

CS ACNS.C.PBN.501 Applicability (See GM1 ACNS.C.PBN.501)

Subsection 5 provides the supplementary functional and performance criteria that are applicable to vertical navigation function for final approach.

[Issue: CS-ACNS/2]

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 83 of 270

GM1 ACNS.C.PBN.501 Applicability Subsection 5 sets out the certification specifications for systems that use either a barometric VNAV (BARO-VNAV) or a GNSS space-based augmented source of vertical position (SBAS-VNAV) for procedures where vertical guidance is based on a published vertical path to LNAV/VNAV or Localizer Performance with Vertical guidance (LPV) minima respectively.

The vertical performance of systems that comply with CS ACNS.C.PBN.555 is not adequate to support required navigation performance (RNP) authorisation required approach (AR APCH) operations, but the requirements contained in CS ACNS.C.PBN.670 should be applied instead.

[Issue: CS-ACNS/2]

[Issue: CS-ACNS/4]

SUPPLEMENTARY FUNCTIONAL CRITERIA

RNP system

CS ACNS.C.PBN.505 Vertical approach path (See GM1 ACNS.C.PBN.5015)

The RNP system has the capability to define a vertical approach path.

[Issue: CS-ACNS/2]

AMC 1 ACNS.C.PBN.505 Vertical approach path The installation of equipment with an ETSO authorisation against ETSO-C115d or ETSO-C146c Class 3 or 4 satisfies the requirement.

[Reference: ED-75D § 3.2.8.4.3]

[Issue: CS-ACNS/2]

CS ACNS.C.PBN.515 Pressure settings (See GM1 ACNS.C.PBN.515)

Where barometric VNAV is provided, the RNP system uses the same pressure-setting input as the aircraft’s altimetry system.

[Issue: CS-ACNS/2]

GM1 ACNS.C.PBN.515 Pressure settings This requirement is intended to prevent potential flight crew errors due to different altimeter settings in the aircraft altimeter system and RNP system.

[Issue: CS-ACNS/2]

CS ACNS.C.PBN.520 Glide path intercept (See AMC1 ACNS.C.PBN.520)

The RNP system has the capability to automatically intercept the final approach glide path.

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 84 of 270

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.520 Glide path intercept The RNP system should allow the glide path to be intercepted at the final approach fix (FAF) using a fly-by technique with a normal acceleration factor of not less than 0.03 g.

The installation of equipment with an ETSO authorisation against ETSO-C115d or ETSO-C146c Class 3 or 4 satisfies the requirement.

[Reference: ED-75D § 3.2.8.5]

CS ACNS.C.PBN.525 Temperature compensation (See AMC1 ACNS.C.PBN.525)

(a) For operations below the promulgated temperature limits on RNP APCH procedures down to LNAV/VNAV minima, area navigation systems that provide barometric VNAV apply automatic temperature compensation along the final approach segment (FAS).

(b) If the automatic temperature compensation is also provided outside the FAS of the procedure, the function providing automatic temperature compensation is pilot-selectable.

(c) Systems supporting pilot-selectable automatic temperature compensation, either within or outside of the FAS, provide a clear and distinct indication when the function is activated.

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.525 Temperature compensation The RNP system providing temperature compensation capability for the vertical path should comply with EUROCAE ED-75D, Appendix H.2.

The capability to provide automatic temperature compensation is an optional function for ETSO authorisation against ETSO C115d. Consequently, the applicant should ensure that this function has been implemented into the RNP system.

[Issue: CS-ACNS/2]

Display of navigation data

CS ACNS.C.PBN.530 Vertical deviation display (See AMC1 ACNS.C.PBN.530 and AMC2 ACNS.C.PBN.530)

The RNP system continuously displays, on the non-numeric vertical deviation display located in the flight crew’s optimum field of view, the deviation from the defined vertical approach path, including the extended vertical approach path.

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.530 Vertical deviation display Deviations from the defined path should be displayed in a timely fashion to support the flight crew to intercept the extended vertical approach path.

[Issue: CS-ACNS/2]

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 85 of 270

AMC2 ACNS.C.PBN.530 Vertical deviation display Installation of equipment with an ETSO authorisation against ETSO-C115d or ETSO-C146c supports the requirement, provided that the applicant ensures the display characteristics comply with this CS.

[Reference: ED-75D § 3.7.5.1.2.1 and § 3.7.5.1.4]

[Issue: CS-ACNS/2]

CS ACNS.C.PBN.535 Resolution and full-scale deflection of the vertical deviation display (See AMC1 ACNS.C.PBN.535 and GM1 ACNS.C.PBN.535)

The vertical deviation display has a resolution and a full-scale deflection that suitably supports the monitoring and bounding of the vertical deviation.

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.535 Resolution and full-scale deflection of the vertical deviation display Compliance with CS ACNS.C.PBN.535 can be demonstrated with one of the following ways:

(1) Installation of equipment with an ETSO authorisation against ETSO-C115d or ETSO-C146c supports the requirement of the CS, provided that the applicant ensures that the display characteristics comply with the CS.

(2) Required navigation performance (RNP) systems that provide fixed vertical scaling should provide a non-numerical vertical deviation display with a full-scale deflection of ± 150 ft. In addition, the display should provide the flight crew with an easy way to readily identify a path deviation of 75 ft using the vertical deviation display alone, i.e. provide clear markings at + 75 ft and at – 75 ft.

Note: Subject to EASA’s agreement, the use of a scale of other than ± 150 ft may be accepted, provided that the scaling is suitable to control the aircraft on the intended path, and the 75-ft deviation can be easily identified by the flight crew. The applicant should provide a human factors and workload assessment, as well as relevant operating procedures that ensure that the aircraft’s deviation from the path can be monitored and bounded within the ± 75-ft interval, supporting this deviation.

(3) Systems that use a type of angular vertical scaling other than the scaling defined in RTCA DO-229D should meet the following:

(a) The deviation scaling suitably supports the flight technical error (FTE) monitoring and bounding (± 75-ft deviation);

(b) The deviation limits are equivalent to the operational limits for glideslope deviations during an ILS approach.

To meet the primary safety objective of not exceeding an FTE of 75 ft below the path to maintain obstacle clearance, it may be required to put a limitation on the length of the approach that the RNP system is able to support.

A vertical situation display is not considered to satisfy the requirements.

[Issue: CS-ACNS/2]

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 86 of 270

[Issue: CS-ACNS/4]

GM1 ACNS.C.PBN.535 Resolution and full-scale deflection of the vertical deviation display Vertical deviation displays that rely on the flight crew to assess the deviation based on whether or not the pointer still touches a marker are not considered acceptable. Neither does EASA consider solutions requiring the flight crew to verify the vertical deviation on a (multifunction) control display unit ((M)CDU) acceptable.

[Issue: CS-ACNS/2]

CS ACNS.C.PBN.540 Barometric altitude When the approach is supported by barometric VNAV, the aircraft displays the barometric altitude from two independent altimetry sources:

(a) one in each of the flight crew’s optimum field of view, if the required minimum flight crew is two; or

(b) one in the flight crew’s optimum field of view and the other visible from the flight crew’s normal position, if the required minimum flight crew is one.

[Issue: CS-ACNS/2]

CS ACNS.C.PBN.545 Active approach mode display If the RNP system provides both barometric VNAV and SBAS/GNSS VNAV, an unambiguous indication is provided in the flight crew’s maximum field of view that enables the flight crew to identify the active source for the VNAV, barometric altitude or SBAS/GNSS geometric altitude.

[Issue: CS-ACNS/2]

Monitoring and alerting

CS ACNS.C.PBN.550 Glide path alerting (See AMC1 ACNS.C.PBN.550)

For approaches to LPV minima, aircraft equipped with a Class A TAWS provide an alert for excessive deviation below the glide path.

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.550 Glide path alerting The excessive-deviation-below-the-glide-path alert may be provided by another system other than the TAWS. If this is the case, the alert should have equivalent effect to the Mode 5 alert provided by a Class A TAWS system.

Note: Applicants are highly encouraged to install a similar glide path deviation alerting function for systems that support RNP APCH down to LNAV/VNAV minima.

[Issue: CS-ACNS/2]

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 87 of 270

SUPPLEMENTARY PERFORMANCE CRITERIA

Vertical performance

CS ACNS.C.PBN.555 Vertical accuracy when using barometric VNAV (See AMC1 ACNS.C.PBN.555)

The accuracy of the vertical position that is provided by the RNP system when providing barometric VNAV supports the intended operations.

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.555 Vertical accuracy when using barometric VNAV When supporting VNAV, the vertical total system error (TSEZ), taking into account all the errors in the aircraft processing chain of the vertical guidance, should be lower than or equal to the values specified in the table below.

Altitude bands Level flight segments & climb/descent intercept of clearance altitudes

Flight along specified vertical descent profile

At or below 5 000 ft MSL 150 ft 160 ft

Above 5 000 to 29 000 ft MSL 200 ft 210 ft

Above 29 000 to 41 000 ft MSL 200 ft 260 ft

Maximum vertical total system error (TSEZ)

TSEZ should be calculated as the combination of the altimetry system error (ASE), the vertical path steering error (PSEZ), the vertical path definition error (PDEZ) and the horizontal coupling error (HCE) — see the figure below. Vertical navigation accuracy (TSEZ) is expected to be achieved for at least 99.7 % of the flight time. Assuming that these four errors are Gaussian and independent, the distribution of TSEz is also Gaussian with a standard deviation equal to the root sum square (RSS) of the standard deviations of the ASE, PSEZ, PDEZ, and HCE.

= √2 + 2 +

2 + 2

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 88 of 270

Vertical errors

(a) Altimetry system error (ASE)

Altimetry system performance is demonstrated separately from the VNAV certification through the static pressure system certification process (e.g. CS XX.1325). Altimetry systems that meet such a requirement satisfy the ASE requirements for VNAV operations. No further demonstration or compliance is necessary, and the following formula should be used to calculate the ASE (in ft) as a function of the aircraft altitude H (in ft), representing the maximum value which is expected to be achieved for at least 99.7 % of the flight time.

= − 8.8 × 10−8 × 2 + 6.5 × 10−3 × + 50

(b) Vertical path definition error (PDEZ)

VNAV path definition error is the error associated to the vertical path computation. It includes path definition error (PDE) and the approximation made by the VNAV equipment for the vertical path construction, if any. This is addressed through equipment approval (ETSO).

(c) Horizontal coupling error (HCE)

HCE (vertical error component of along-track positioning error) is a function of the horizontal NSE and is directly reflected in the along-track tolerance offset used in BARO-VNAV procedure design criteria. The HCE should only be taken into account in the final approach segment.

HCE is expected to be achieved for at least 99.7 % of the flight time and, in this context, may be assumed to be equal to 24 ft on a vertical path of 3 degrees°.

(d) Vertical path steering error (PSEZ)

The vertical path steering performance varies depending on how operations are conducted (manual, flight director or autopilot). The use of a flight director or autopilot may be required to support the PSEZ requirement in certain conditions. In this case, the required navigation performance (RNP) system coupling to the flight director and/or autopilot should be unambiguously displayed in the flight crew’s optimum field of view. This should also be documented in the AFM.

[Issue: CS-ACNS/2]

[Issue: CS-ACNS/4]

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 89 of 270

CS ACNS.C.PBN.560 Vertical accuracy when using SBAS/GNSS geometric altitude sources (See AMC1 ACNS.C.PBN.560 and GM1 ACNS.C.PBN.560)

When supporting approach operations down to LNAV/VNAV or LPV minima using SBAS/GNSS vertical position source, the accuracy of the RNP system is demonstrated to be suitable for the intended operation.

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.560 Vertical accuracy when using SBAS/GNSS geometric altitude sources The vertical total system error (TSEZ) is dependent on the navigation system error (NSE), the path definition error (PDEZ) and the flight technical error (FTEZ).

(a) Navigation system error (NSE)

The NSE should be within the accuracy requirements of ICAO Annex 10, Volume 1 to the Chicago Convention with respect to signal-in-space performance. These NSE requirements are considered to be fulfilled without any demonstration if the equipment has been granted an ETSO authorisation against ETSO-C145c, operational Class 3 or ETSO-C146c, operational Class 3 or 4.

(b) Flight technical error (FTEZ)

FTEZ is considered to be equivalent to the ILS approach if the angular deviations are displayed to the flight crew on the existing or comparable display, and the system meets the integration criteria of paragraph 7(a) of Appendix C to Subpart C of CS-ACNS and the SBAS/GNSS receiver has been granted an ETSO authorisation against ETSO-C145c, operational Class 3 or ETSO- C146c, operational Class 3 or 4.

For flight guidance systems, the FTEZ performance is considered acceptable if it meets the criteria of paragraph 7(a) of Appendix C to Subpart C of CS-ACNS and the SBAS/GNSS receiver has been granted an ETSO authorisation against ETSO-C145c, operational Class 3 or ETSO- C146c, operational Class 3 or 4.

(c) Path definition error (PDEZ)

For approaches to LPV minima, there are no performance or demonstration requirements for PDEZ. PDEZ is considered negligible based on the requirements for the FAS data block generation process.

For approaches to LNAV/VNAV minima, the applicant may assume that the PDEZ is negligible, provided that the RNP system’s internal resolution is equal to or better than the resolution provided for the path definition.

[Issue: CS-ACNS/2]

GM1 ACNS.C.PBN.560 Vertical accuracy when using SBAS/GNSS geometric altitude sources The lateral and vertical full-scale deflection requirements detailed in RTCA DO-229D, which is the basis for ETSO-C145c (operational Class 3) and ETSO-C146c (operational Class 3 or 4), ensure an ILS

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 90 of 270

‘lookalike’ presentation. The deflection may be fully angular with no limitation or angular but bounded at a certain value (e.g. bounded at ± 1 NM laterally and ± 150 m vertically).

[Issue: CS-ACNS/2]

CS ACNS.C.PBN.565 Transitions (See AMC1 ACNS.C.PBN.565)

RNP systems that provide both barometric VNAV and SBAS/GNSS VNAV perform smooth transitions from barometric VNAV to SBAS/GNSS VNAV and vice versa.

[Issue: CS-ACNS/2]

AMC 1 ACNS.C.PBN.565 Transitions Transitions from one source of VNAV to another should not cause discontinuities or transients that have the potential to destabilise the aircraft on final or missed approach. Aspects to consider when transitioning from one source to the other include:

(a) temperature errors, particularly if operating outside the allowable BARO-VNAV temperature range;

(b) MSL versus WGS-84 ellipsoid for path definition;

(c) curved BARO-VNAV path versus straight SBAS/GNSS path; and

(d) linear BARO-VNAV guidance versus angular SBAS/GNSS guidance.

[Issue: CS-ACNS/2]

CS ACNS.C.PBN.570 Advisory VNAV (See AMC1 ACNS.C.PBN.570 and GM1 ACNS.C.PBN.570)

(a) RNP systems that provide advisory VNAV comply with the criteria of this Subsection for barometric VNAV or SBAS/GNSS VNAV:

(1) Advisory VNAV provided within the FAS that is based on barometric altitude meets the intent of the temperature compensation function defined in CS ACNS.C.PBN.525.

(2) When Advisory VNAV is provided and the performance criteria of this Subsection for barometric VNAV or SBAS/GNSS VNAV cannot be met, a clear and unambiguous indication that the VNAV is advisory is provided.

(b) Advisory VNAV is based on a correct path definition:

(1) Either provided by the State’s AIP; or

(2) Through an alternative approved process.

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.570 Advisory VNAV Attachment 5 to ARINC 424 provides an acceptable method of origination of the data.

If the data does not originate from an authoritative source, the data should be validated in accordance with ED-76A, Section 2.4.1, item 6.

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 91 of 270

[Issue: CS-ACNS/2]

GM1 ACNS.C.PBN.570 Advisory VNAV With reference to (a)(2), the indication should be plain and easy to interpret to avoid confusion. The use of typographic characters (e.g. ‘+’ or ‘/’) as the only means to distinguish whether the vertical guidance is advisory or is referenced to a published procedure is not considered adequate.

The use of the function should be documented in AFM, pilot operating handbook (POH) or similar documents and supplements to these documents and should contain a statement to inform the flight crew that, when advisory VNAV is provided, the primary barometric altimeter should be used as the primary reference for compliance with all altitude restrictions that are associated with the instrument approach procedure, including compliance with step-down fixes.

[Issue: CS-ACNS/2]

CS ACNS.C.PBN.575 RNP system design — integrity in final approach (See AMC1 ACNS.C.PBN.575)

The integrity of the vertical guidance provided by the aircraft’s RNP system supports the intended operations.

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.575 RNP system design — integrity in final approach Guidance on the integrity (provisioning of erroneous output or display of data) by the RNP system related to vertical position or guidance is provided in Appendix A to Subpart C.

[Issue: CS-ACNS/2]

CS ACNS.C.PBN.580 RNP system design — continuity (See AMC1 ACNS.C.PBN.580)

The continuity of vertical guidance provided by the RNP system supports the intended operation.

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.580 RNP system design — continuity Guidance on the continuity (loss of the function) of the RNP system to provide vertical position or guidance is provided in Appendix A to Subpart C.

[Issue: CS-ACNS/2]

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 92 of 270

SUBSECTION 6 – SUPPLEMENTARY SPECIFICATIONS FOR RNP AUTHORISATION

REQUIRED (RNP AR)

APPLICABILITY

CS ACNS.C.PBN.601 Applicability Subsection 6 provides the supplementary functional and performance criteria that are applicable to obtain certification for RNP AR APCH. Criteria for RNP AR departures (RNP AR DP) are provided consistently with the draft ICAO Navigation Specification for RNP AR departures.

The criteria of Subsection 6 only apply to operations on RNP AR procedures designed in accordance with the requirements of ICAO Doc 9905 ‘Required Navigation Performance Authorization Required (RNP AR) Procedure Design Manual.

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.601 Applicability Compliance with the criteria of CS-ACNS for RNP AR operations ensure that the probability of the aircraft exiting the lateral or vertical extent of the obstacle clearance volume of the procedure (i.e. 2 x RNP and – 75 ft.) does not exceed 10-7 per procedure; in the case of RNP AR APCH, this includes the missed approach.

Applicants who deviate from the criteria in Subsection 6 should demonstrate that they meet the aforementioned objective.

[Issue: CS-ACNS/2]

GM1 ACNS.C.PBN.601 Applicability Compliance demonstration of aircraft eligibility for RNP AR approval is often a long and very demanding process. It requires full and unrestricted access to the aircraft’s safety (i.e. the data used to support compliance with CS XX.1309), aerodynamics and performance data. Furthermore, the applicant should have, as a minimum, access to a representative simulator for prolonged periods of time. Occasionally, access to the aircraft for flight testing will be required.

More stringent criteria may apply to aircraft that operate with special or proprietary procedures which are not designed to conform to ICAO Doc 9905.

Applicants who intend to apply for RNP AR approval are encouraged to contact EASA at the earliest opportunity to discuss the technical details of the compliance demonstration.

[Issue: CS-ACNS/2]

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 93 of 270

SUPPLEMENTARY SYSTEM QUALIFICATION

CS ACNS.C.PBN.605 System performance demonstration (See AMC1 ACNS.C.PBN.605 and GM1 ACNS.C.PBN.605)

The performance (including the RF function) of the aircraft’s system is demonstrated under a variety of operational, meteorological, and failure conditions, commensurate with the intended operation.

Criteria for assessing RNP significant failures under design limit performance conditions are the following:

(a) the lateral excursions observed as a result of probable failures are contained within a 1 × RNP corridor;

(b) the lateral excursions observed as a result of one-engine-inoperative (OEI) are contained within a 1 × RNP corridor;

(c) the lateral excursions observed as a result of remote failures are contained within a 2 × RNP corridor; and

(d) a demonstration is made that the aircraft remains manoeuvrable and a safe extraction can be flown for all extremely remote failures.

For criteria (a), (b), and (c) above, the vertical excursion does not exceed 75 feet below the desired path.

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.605 System performance demonstration The applicant should demonstrate the aircraft capability in terms of performance under design limit operational conditions (e.g. tailwinds and crosswinds, centre-of-gravity (CG) limits, temperature limits), and on representative procedures that include RF legs of varying radii. The applicant should also assess the effects of configuration changes (e.g. gear and flap extension and retraction).

The applicant should conduct a safety impact assessment based on the aircraft’s system safety assessments (SSAs) and identify any failure conditions that could potentially impact on performance. The functional hazard assessment (FHA) and SSA of all the aircraft’s systems that support RNP AR operations (RNAV systems, flight controls systems, flight guidance systems, displays, etc.) should, therefore, be revisited to identify these failures. System failures should include latent failures (‘integrity’) and detected failures (‘continuity’). For the detected failures, the monitor limit of the alert, the time to alert, the flight crew reaction time, and the aircraft response should all be taken into account and verified to ensure that the aircraft does not exit the obstacle clearance volume.

The intent of this requirement is to ensure robustness of the aircraft and its systems to failure conditions. Consequently, performing a safe extraction contingency procedure, i.e. initiating a missed approach, is not an acceptable means of demonstrating compliance against the criteria of CS ACNS.C.PBN.605(a), (b), and (c). These demonstrations may rely on crew action to intervene and place the aircraft back on the target track even if, in an operational environment, the crew is expected to initiate a missed approach procedure when the lateral or vertical criteria are exceeded. For compliance demonstration purposes, however, executing a safe extraction is not considered appropriate for demonstration of compliance with these criteria.

(a) With reference to CS ACNS.C.PBN.605(a), any failure that is classified as ‘probable’ and supports the RNP AR operation should be assessed. Those failures that would require the flight crew to

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 94 of 270

act or intervene should be assessed in a representative environment and design limit operational conditions by the applicant’s flight test pilots. The impact of the failure and the flight crew intervention should be such that the aircraft can be maintained within the 1 × RNP value and within – 75 ft altitude deviation.

(b) With reference to CS ACNS.C.PBN.605(b), the same requirements apply for the case of an engine failure. If the engine failure would require the flight crew to act or intervene, then this should be assessed in a representative environment and design limit operational conditions by the applicant’s flight test pilots. The impact of the failure and the flight crew intervention should be such that the aircraft can be maintained within the 1 × RNP value and within – 75 ft altitude deviation.

(c) With reference to CS ACNS.C.PBN.605(c), the same requirements apply, except that, for the case of failures classified as ‘remote’ but not ‘extremely remote’, the impact of the failure and the flight crew intervention should be such that the aircraft can be maintained within the 2 × RNP value and within – 75 ft altitude deviation.

(d) With reference to CS ACNS.C.PBN.605(d), the applicant should demonstrate that no ‘extremely remote’ failure limits the flight crew’s ability to:

— intervene and place the aircraft back on the target track contained within the alert threshold; or

— safely extract the aircraft through manual intervention.

Safe extraction is defined as within 2 × RNP for the applicable approach and missed approach procedure, until such time that the aircraft is stabilised and reaches a safe altitude. The RNP for the missed approach procedure is usually higher than the RNP for the continued approach. For extremely remote navigational failure conditions (e.g. all flight management computers (FMCs) failed), the flight crew must be able to navigate the aircraft free of obstacles.

For departure procedures with close-in RF legs at or just beyond the departure end of the runway, and for missed approach procedures with close-in RF legs, the retraction of the landing gear and flaps and subsequent rapid acceleration may affect the RNP system’s ability to conduct accurate turn anticipation. An inaccurate turn anticipation calculation may result in an overshoot of a close-in RF turn. When this performance characteristic is present, the applicant should consider including a limiting airspeed for the initial phase of the departure or the missed approach in the AFM. The airspeed limit should not be lower than the best-climb airspeed with one-engine-inoperative.

The severity level of the above demonstrations (failure conditions in combination with the RNP approach containment requirements), as assessed by the test pilot, must still match the probability of the applicable failure condition (ref.: CS 25.1309).

Specific evaluations should be conducted to assess path excursions upon failures and the resulting RNP levels. Results should be documented in the AFM, AFM Supplement, or any appropriate aircraft operational support document which is approved by EASA and made available to the operator. In other words: If, for example, the worst-case result of the assessments that have been conducted to demonstrate compliance for ‘remote’ failures shows that the aeroplane diverts 0.40 NM from the published track, then the applicant should limit the authorised RNP to 0.20 NM.

[Issue: CS-ACNS/2]

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 95 of 270

GM1 ACNS.C.PBN.605 System performance demonstration As regards applications for RNP AR approval, the involvement of flight test pilots in this exercise has been shown to be crucial. Flight crew intervention is an essential aspect of these demonstrations and on occasion it has been proven difficult for flight crews to timely recognise the failure and intervene adequately. An appropriate level of specific training for RNP AR operations may be assumed.

[Issue: CS-ACNS/2]

CS ACNS.C.PBN.610 Source of horizontal position (See AMC1 ACNS.C.PBN.610 and GM1 ACNS.C.PBN.610)

(a) The RNP system utilises the global navigation satellite system (GNSS) as primary source of horizontal position and is backed by an inertial position source.

(b) The aircraft's RNP system does not use VOR-updating when conducting RNP AR APCH procedures.

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.610 Source of horizontal position As a minimum, the inertial positioning source needs to comply with the criteria of Appendix B. The applicant should, however, demonstrate that circular error of the inertial system supports a safe extraction, as defined in AMC1 ACNS.C.PBN.605 in case of loss of GNSS. This may imply that the design of the inertial position source needs to exceed the performance criteria described in Appendix B.

If the RNP system does not exclude VOR-updating automatically, the applicant should identify any pilot procedures for an aircraft to comply with this requirement.

[Issue: CS-ACNS/2]

GM1 ACNS.C.PBN.610 Source of horizontal position Integrated global navigation satellite system/inertial navigation system (GNSS/INS) or global navigation satellite system/inertial reference unit (GNSS/IRU) position solutions reduce the rate of degradation after loss of position updating. The use of a ‘tightly coupled’ GNSS/inertial system to support RNP AR operations is recommended. For ‘tightly coupled’ GNSS/inertial systems, RTCA/DO- 229D Appendix R provides additional guidance.

INS or IRU are generally not considered suitable as a sole source of horizontal position for RNP AR applications described herein. However, it is recognised that many multi-sensor navigation systems utilise INS or IRU within their navigation calculations to provide continuity when the other higher accuracy sensor(s) is (are) momentarily unavailable.

Attitude and heading reference systems (AHRSs), including an AHRS with inputs from air-data computers, are generally not considered to provide a level of performance that would be adequate to support RNP AR operations, i.e. meet the criteria of Appendix B.

[Issue: CS-ACNS/2]

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 96 of 270

SUPPLEMENTARY FUNCTIONAL CRITERIA

RNP system

CS ACNS.C.PBN.615 Autopilot/Flight director (a) Means are provided to couple the required navigation performance (RNP) system with the

autopilot or flight director.

(b) The RNP system, the flight director system and the autopilot must be capable of commanding a bank angle of up to 30 degrees above 121 m (400 ft) AGL and up to 8 degrees below 121 m (400 ft) AGL.

[Issue: CS-ACNS/2]

[Issue: CS-ACNS/4]

CS ACNS.C.PBN.620 Reversion (See GM1 ACNS.C.PBN.620)

When the RNP cannot be maintained during a radius to fix (RF) leg, the flight guidance mode remains in lateral navigation.

[Issue: CS-ACNS/2]

GM1 ACNS.C.PBN.620 Reversion This requirement is intended to support the flight crew in extracting the aircraft from the procedure.

[Issue: CS-ACNS/2]

CS ACNS.C.PBN.625 Go-around and missed approach (See GM1 ACNS.C.PBN.625)

Upon initiating a go-around or missed approach, both RNP system and the autopilot or flight director remain in lateral navigation guidance mode and continue to guide the aircraft along the lateral path of the procedure until completion of the approach and missed approach procedure.

[Issue: CS-ACNS/2]

GM1 ACNS.C.PBN.625 Go-around and missed approach Loss of the RNP capability is considered as a condition that would require the initiation of a missed approach.

[Issue: CS-ACNS/2]

CS ACNS.C.PBN.630 Radius to fix (RF) leg transition (See AMC1 ACNS.C.PBN.630)

The RNP system has the capability to execute the radius to fix (RF) leg transitions and to consistently maintain tracks, as specified in Subsection 8.

[Issue: CS-ACNS/2]

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 97 of 270

AMC1 ACNS.C.PBN.630 Radius to fix (RF) leg transition The demonstration of the RF capability should be undertaken considering:

(a) limit wind speed;

(b) turn radius;

(c) configuration changes;

(d) failure conditions.

With reference to failure conditions (d), the unique requirements on demonstration of performance under failure conditions of CS ACNS.C.PBN.605 apply.

[Issue: CS-ACNS/2]

CS ACNS.C.PBN.635 Navigation accuracy for RNP AR operations (See AMC1 ACNS.C.PBN.635)

The RNP system is capable of acquiring the RNP value associated with the intended operation.

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.635 Navigation accuracy for RNP AR operations If the RNP system offers multiple RNP values associated with lines of minima on an RNP AR approach procedure, the system should allow the flight crew to select the RNP values associated with the appropriate line of minima for use on the final approach segment. The system should then acquire the associated RNP value(s) for the procedure from the navigation database.

[Issue: CS-ACNS/2]

CS ACNS.C.PBN.640 RNP AR departures – Functional Requirements (See AMC1 ACNS.C.PBN.640 and GM1 ACNS.C.PBN.640)

The RNP system provides the following capabilities to support RNP AR departure procedures:

(a) The RNP system allows loading and execution of a flight plan where the initial fix of the RNP AR DP defined path is placed at or just beyond the approach end of the take-off runway.

(b) The RNP system provides lateral path guidance not later than when reaching 50 feet above the departure runway.

(c) The RNP system is capable of executing an RF leg where the first fix defining the RF leg begins at the departure end of the runway.

(d) The RNP system provides a means for the flight crew to confirm availability of GNSS for aircraft positioning immediately prior to take-off.

(e) The INS position is automatically updated upon pressing the take-off/go-around (TOGA) button or provide the ability to manually initiate a position update during ground operations immediately prior to take-off.

[Issue: CS-ACNS/2]

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 98 of 270

AMC1 ACNS.C.PBN.640 RNP AR departures With reference to (c), when the RNP AR DP requires a close-in turn at or just beyond the DER, retraction of the landing gear and flaps during the take-off sequence and subsequent rapid acceleration to en-route climb airspeed may compromise the RNP system’s ability to conduct accurate turn anticipation for the close-in turns, possibly resulting in the aircraft’s inability to comply with the defined turn (i.e. overshoot a close-in RF turn). Limiting the airspeed for the initial phase of the departure can help ensure the RNP system’s turn anticipation calculations are accurate.

With reference to (e), if the aircraft requires the flight crew to conduct a manual INS position update immediately prior to take-off, the applicant should provide procedures requiring the air crew to conduct the position update within 300 meter (1 000 ft) of the start point of the aircraft’s take-off roll.

[Issue: CS-ACNS/2]

GM1 ACNS.C.PBN.640 RNP AR departures With reference to (a), locating an initial fix of an RNP AR DP at or just beyond the approach end of the take-off runway is one acceptable means to facilitate executing an RF leg at the departure end of the runway (DER). The straight segment from the initial fix leading to the fix defining the beginning of the RF leg at the DER helps ensure the aircraft’s path is tangent to the RF leg in order to capture of the RF leg guidance.

[Issue: CS-ACNS/2]

CS ACNS.C.PBN.645 RNP AR departures – Take off performance Data In support of RNP AR departures, the applicant provides aircraft take off performance data, including performance on non-standard climb gradients, to the operator in a form acceptable to EASA.

[Issue: CS-ACNS/2]

Display of navigation data

CS ACNS.C.PBN.650 Display of aircraft track The RNP system displays the desired and current aircraft track on an electronic map display in the flight crew’s optimum field of view.

[Issue: CS-ACNS/2]

CS ACNS.C.PBN.655 Lateral deviation display (See AMC1 ACNS.C.PBN.655)

The full-scale deflection of the non-numeric lateral deviation display supports the intended operation.

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.655 Lateral deviation display The full-scale deflection of the non-numeric lateral deviation display should not be greater than two (2) times the applicable RNP.

[Issue: CS-ACNS/2]

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 99 of 270

Navigation database

CS ACNS.C.PBN.660 Use of a navigation database (See AMC1 ACNS.C.PBN.660)

The RNP system uses an on-board navigation database which provides sufficient data resolution to ensure that the RNP system achieves the required accuracy to support RNP AR operations.

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.660 Use of a navigation database Waypoint definition error should be less than or equal to 60 feet, including both the data storage resolution and the RNP system computational resolution used internally for the construction of flight plan waypoints.

The navigation database should contain vertical angles (glide path angles) stored to a resolution of hundredths of a degree, with equivalent computational resolution.

[Issue: CS-ACNS/2]

Vertical performance

CS ACNS.C.PBN.670 Vertical accuracy (See AMC1 ACNS.C.PBN.670 and AMC2 ACNS.C.PBN.670)

The vertical position accuracy supports the intended RNP AR operations.

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.670 Vertical accuracy When the vertical position is provided by BARO-VNAV and the aircraft performs stabilised constant descent path, the RNP system should ensure that 99.7 % of the system error in the vertical position is equal to or less than the vertical error budget (VEB) attributed to the aircraft, as defined by (in feet):

= √2 + 2 + 2 + 2

Where:

ANPE = actual navigation performance error which can be computed as follows:

= 6076.115 × 1.225 × × ()

WPR = waypoint precision error which can be computed as follows:

= 60 × ()

FTE = flight technical error which can be assumed to be 75 feet with autopilot or flight director coupled.

ASE = altimetry system error which can be computed as follows:

= − 8.8. 10−8 × (ℎ + ∆ℎ)2 + 6.5. 10−3(ℎ + ∆ℎ) + 50

Using:

— ‘θ’ as the vertical navigation (VNAV) path angle;

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 100 of 270

— ‘h’ as the height in feet of the local altimetry reporting station; and

— ‘Δh’ as the height in feet of the aircraft above the reporting station.

Note: VEBaircraft contains the elements out of the minimum obstacle clearance (MOC) equation in Appendix 1 to ICAO Document 9905 ‘Required Navigation Performance Authorization Required Procedure Design Manual’, which are attributed to the aircraft. The applicant should not apply the other elements of the MOC equation, i.e. body geometry (bg) error or international standard atmosphere temperature deviation (isad), in support of demonstration of vertical accuracy.

[Issue: CS-ACNS/2]

AMC2 ACNS.C.PBN.670 Vertical accuracy Where SBAS/GNSS geometric altitude is used, the installation of equipment that supports a 50-m vertical alert limit (VAL) satisfies the requirement for operations down to RNP 0.3 and the installation of equipment that supports a 35-m vertical alert limit (VAL) satisfies the requirement for operations down to RNP 0.1.

[Issue: CS-ACNS/2]

SUPPLEMENTARY PERFORMANCE CRITERIA

CS ACNS.C.PBN.675 RNP system design – RNP AR integrity (See AMC1 ACNS.C.PBN.675 and GM1 ACNS.C.PBN.675)

The integrity of the guidance provided by the aircraft required navigation performance (RNP) system supports the intended RNP AR operations.

[Issue: CS-ACNS/2]

[Issue: CS-ACNS/4]

AMC1 ACNS.C.PBN.675 RNP system design — RNP AR integrity Guidance on the integrity (provisioning of erroneous output or display of data) of the RNP system related to RNP AR operations is provided in Appendix A to Subpart C.

[Issue: CS-ACNS/2]

GM1 ACNS.C.PBN.675 RNP system design – RNP AR integrity The criterion of CS ACNS.C.PBN.675 applies to the integrity of the design of the system(s) that provide(s) guidance on lateral navigation (LNAV) and vertical navigation (VNAV), e.g. the design assurance level (DAL). It does not apply to the integrity of the VNAV performance.

[Issue: CS-ACNS/4]

CS ACNS.C.PBN.680 RNP system design – RNP AR continuity (See AMC1 ACNS.C.PBN.680 and GM1 ACNS.C.PBN.680)

The continuity of the guidance provided by the required navigation performance (RNP) system supports the intended RNP AR operations.

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 101 of 270

[Issue: CS-ACNS/2]

[Issue: CS-ACNS/4]

AMC1 ACNS.C.PBN.680 RNP system design — RNP AR continuity Guidance on the continuity (loss of the function) of the RNP system to provide lateral and vertical position or guidance is provided in Appendix A to Subpart C.

[Issue: CS-ACNS/2]

GM1 ACNS.C.PBN.680 RNP system design – RNP AR continuity The criterion of CS ACNS.C.PBN.680 applies to the continuity of the design of the required navigation performance (RNP) system(s) that provide(s) guidance on lateral navigation (LNAV) and vertical navigation (VNAV). It does not imply recognition of, or a step towards, vertical RNP or similar concepts.

[Issue: CS-ACNS/4]

SUBSECTION 7 – SUPPLEMENTARY SPECIFICATIONS FOR APPLICATIONS FOR

ADVANCED RNP (A-RNP)

APPLICABILITY

CS ACNS.C.PBN.701 Applicability Subsection 7 provides the supplementary functional and performance criteria that are applicable to obtain certification for applications for advanced-RNP (A-RNP).

[Issue: CS-ACNS/2]

SUPPLEMENTARY FUNCTIONAL CRITERIA

RNP system

CS ACNS.C.PBN.705 Radius to Fix The RNP system has the capability to execute radius to Fix (RF) legs (as specified in Subsection 8).

[Issue: CS-ACNS/2]

CS ACNS.C.PBN.710 Parallel offset The RNP system has the capability to implement parallel offset (as specified in Subsection 10).

[Issue: CS-ACNS/2]

CS ACNS.C.PBN.715 RNP scalability The RNP system has the capability to operate with RNP values (ranging from 0.3 to 1.0 NM in tenth(s) of NM). The RNP value is either retrievable automatically from the on-board navigation database or manually adjustable by the flight crew.

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 102 of 270

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.715 RNP scalability Installation of equipment with an ETSO authorisation against ETSO-C115d satisfies the requirement.

[References: ED-75D § 3.7.2.1.3.1, ED-75D § 3.2.6, ED-75D § 3.2.6.2]

[Issue: CS-ACNS/2]

Display of navigation data

CS ACNS.C.PBN.725 Display of aircraft track The RNP system displays the current aircraft track (or track angle error) in the flight crew’s optimum field of view.

[Issue: CS-ACNS/2]

SUBSECTION 8 – SUPPLEMENTARY SPECIFICATIONS SUPPORTING RADIUS TO FIX

(RF)

APPLICABILITY

CS ACNS.C.PBN.801 Applicability Subsection 8 provides the supplementary functional and performance criteria that are applicable to obtain certification for the capability to execute radius to fix (RF) path terminators.

The RF functionality is mandatory to obtain A-RNP and RNP AR certification, and can be optionally associated with RNP 1, RNP 0.3 and RNP APCH.

[Issue: CS-ACNS/2]

SUPPLEMENTARY FUNCTIONAL CRITERIA

RNP system

CS ACNS.C.PBN.805 RF functional requirements (See AMC1 ACNS.C.PBN.805 and GM1 ACNS.C.PBN.805)

The RNP system coupled with an autopilot or a flight director is capable of:

(a) executing the radius to fix (RF) legs; and

(b) commanding and achieving a minimum bank angle of up to 30 degrees above 400 feet above ground level (AGL) and up to 8 degrees below 400 feet AGL.

[Issue: CS-ACNS/2]

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 103 of 270

AMC1 ACNS.C.PBN.805 RF functional requirements The applicant should perform an evaluation of the navigation system on a representative set of procedure designs under all foreseen operating conditions. The evaluation should address maximum assumed crosswind and maximum altitude with the aircraft operating in the range of expected airspeeds for the manoeuvre and operating gross weights and CG conditions (i.e. forward/aft). Procedure design constraints should include sequencing multiple, consecutive RF leg segments of varying turn radii, including consecutive RF leg segments reversing the direction of turn (i.e. reversing from a left-hand RF turn to a right-hand RF turn).

When evaluating flight technical error on RF legs, the effect of rolling into and out of the turn should be considered.

Within the demonstration, the applicant should be seeking to confirm that the FTE is commensurate with the RNP navigation accuracy.

Where applicable, the ability of the aircraft to maintain an appropriate FTE after a full or partial failure of the autopilot and/or flight director should also be demonstrated.

Any limitations identified during the compliance demonstration should be documented. Flight crew procedures should be assessed, including identification of any limitations which surround the use of pilot selectable or automatic bank angle limiting functions and confirmation of those related to go- around or missed approach from an RF leg segment.

Test procedures for aircraft capability to perform RF legs in approach and departure should make use of the RF leg demonstration templates described in Appendix D to Subpart C.

[Issue: CS-ACNS/2]

GM1 ACNS.C.PBN.805 RF functional requirements The test procedure is designed to provide 5 degrees of manoeuvrability margin to enable the aircraft to get back on the desired track after a slight overshoot at the start of the turn.

Industry standards for RF defined paths can be found in EUROCAE ED-75D (RTCA DO-236C Change 1).

CS ACNS.C.PBN.810 RNP failure If the RNP cannot be achieved during a radius to fix (RF) leg, the flight guidance mode remains in lateral navigation.

[Issue: CS-ACNS/2]

CS ACNS.C.PBN.815 Autopilot/Flight director (See AMC1 ACNS.C.PBN.815)

The use of autopilot or flight director is required to execute radius to fix (RF) leg transitions, except for CS-23 Level 1, 2, and 3 aircraft, for which no type rating is required, and that are performing RNP 1 and RNP APCH operations with an RNP value of not less than 1, and at speeds of 200 knots or less, provided that, in addition to the requirement stated in CS ACNS.C.PBN.820, the aircraft is equipped with an appropriately scaled course deviation indicator (CDI).

[Issue: CS-ACNS/2]

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 104 of 270

AMC1 ACNS.C.PBN.815 Autopilot/Flight director The applicant should perform an evaluation to demonstrate that the aircraft can be maintained on the desired path, without excessive deviations, under all foreseen operating conditions. The demonstrations should be performed on a representative set of procedure designs.

[Issue: CS-ACNS/2]

Display of navigation data

CS ACNS.C.PBN.820 Display of computed path The RNP system displays the intended path on an appropriately scaled moving map display in the flight crew’s maximum field of view.

[Issue: CS-ACNS/2]

SUBSECTION 9 – SUPPLEMENTARY SPECIFICATIONS SUPPORTING FIXED RADIUS

TRANSITION (FRT)

APPLICABILITY

CS ACNS.C.PBN.901 Applicability Subsection 9 provides the supplementary functional and performance criteria that are applicable to obtain FRT certification.

The FRT functionality can optionally be associated with RNP 2, RNP 4, and advanced RNP (A-RNP) specifications.

[Issue: CS-ACNS/2]

SUPPLEMENTARY FUNCTIONAL CRITERIA

RNP system

CS ACNS.C.PBN.905 Fixed radius transition (FRT) requirements (See AMC1 ACNS.C.PBN.905and GM1 ACNS.C.PBN.905)

The RNP system is capable of defining, executing and maintaining a track consistent with an FRT between flight path segments, using a 0.1-NM resolution for the radius value.

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.905 Fixed radius transition (FRT) requirements The installation of equipment with an ETSO authorisation against ETSO-C115d satisfies the requirement.

[Reference ED-75D § 3.2.5.4.2]

[Issue: CS-ACNS/2]

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 105 of 270

GM1 ACNS.C.PBN.905 Fixed radius transition (FRT) requirements FRT requirements are defined in Aeronautical Radio, Inc. (ARINC) 424, and their application is described in more detail in EUROCAE documents ED-75D (RTCA DO-236C Change 1).

[Issue: CS-ACNS/2]

Display of navigation data

CS ACNS.C.PBN.910 Display of the computed path The RNP system displays the computed curved path of the FRT on an appropriately scaled moving map display in the flight crew’s maximum field of view.

[Issue: CS-ACNS/2]

SUBSECTION 10 – SUPPLEMENTARY SPECIFICATIONS SUPPORTING PARALLEL

OFFSET

APPLICABILITY

CS ACNS.C.PBN.1001 Applicability Subsection 10 provides supplementary functional and performance criteria that are applicable to obtain certification for parallel offset which enables the aircraft to fly a path parallel to, but offset left or right from, the original active route (parent route). Parallel offset is applicable only for en-route segments and is not foreseen to be applied on standard instrument departures (SIDs), standard instrument arrivals (STARs) or approach procedures.

The parallel offset functionality is mandatory to obtain RNP 4 and A-RNP certification, and can be optionally associated with RNP 2 specifications.

[Issue: CS-ACNS/2]

SUPPLEMENTARY FUNCTIONAL CRITERIA

RNP system

CS ACNS.C.PBN.1005 Parallel offset capabilities (See AMC1 ACNS.C.PBN.1005)

(a) The RNP system has the capability to:

(1) define a offset path from the parent track and transit to and from the offset track maintaining an intercept angle of 30 degrees;

(2) manually initiate and cease the parallel offset path;

(3) automatically cancel the offset path:

(i) following an amendment of the active flight plan by executing a ‘direct-to’;

(ii) approaching the first fix of an instrument approach procedure (initial approach fix (IAF), initial fix (IF), or final approach fix (FAF));

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 106 of 270

(iii) approaching the commencement of a segment which is not compatible with the offset.

An advance notice of the automatic cancellation is given to the flight crew and the RNP system allows sufficient time for the aircraft to return to the parent track before the commencement of the incompatible leg or the first fix of the instrument approach procedure.

(b) When executing a parallel offset, the RNP system applies to the offset route all performance requirements and constraints of the original route, as defined in the active flight plan.

[Issue: CS-ACNS/2]

AMC1 ACNS.C.PBN.1005 Parallel offset capabilities The installation of equipment with an ETSO authorisation against ETSO-C115d, Class A, satisfies the requirement.

For RNP systems that have not been granted an ETSO authorisation against ETSO-C115d, Class A, the requirements of ED-75D (RTCA DO-236C Change 1) Section 3.7.2.2.4 ‘Parallel Offsets’ apply, with the following additions:

(a) The RNP system should have the capability to define the offset path from the parent track using an increment of at least 1 NM, left or right and with a total offset of at least 20 NM. Where the RNP system supports the definition of a single, pre-planned parallel offset using specific start and end fixes, the RNP system should:

(1) provide automatic initiation and cessation of the offset at the start and end waypoint;

(2) begin transition to the offset path at the start waypoint on the original path to join the intercept path;

(3) begin the return to the original path so that the return transition ends at the end waypoint on the original path.

With reference to CS ACNS.C.PBN.1005(a) (3)(iii), cases which are not compatible with an offset are considered to be:

(i) arrival at a fix where a course change exceeds 120 degrees;

(ii) a route segment that ends at a hold fix.

(b) When executing a parallel offset, the RNP system computes the offset reference points using the same resolution that the parent route reference points have. Where FRTs are applied, the offset track should be flown with the same turn radius as the parent track.

[Issue: CS-ACNS/2]

Display of navigation data

CS ACNS.C.PBN.1010 Indication of parallel offset status When in offset mode, the RNP system provides:

(a) lateral guidance parameters relative to the offset path;

(b) distance and estimated time of arrival at, or time to go to, information relative to the offset reference points;

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 107 of 270

(c) a continuous indication of the parallel offset status in the flight crew’s maximum field of view; and

(d) the cross-track deviation indication during the operation of the offset relative to the offset track.

[Issue: CS-ACNS/2]

Appendix A — Guidance on classification of Failure Conditions. The following table provides guidance for the classification of failure conditions, based on a generic assessment of the risks related to the execution of the flight procedure as defined in the ICAO navigation specification.

As it is not possible for EASA to consider specific aspects of a particular design or particular mitigations, EASA will consider the outcome of a functional hazard assessment (FHA) applied to the specific design. If no FHA is provided, the higher of the classification is applied.

Type of operation Continuity / Integrity Classification of Failure Conditions

RNP 11, RNP 2, RNP 4, RNP 0.3 Continuity (Loss) Major

Integrity (Erroneous) Major

Advanced RNP, RNP APCH Continuity (Loss) Major2,3

Integrity (Erroneous) Major/Hazardous2

RNP AR APCH, RNP AR DP (RNP ≥ 0.3 NM)

Continuity (Loss) Major/Hazardous3

Integrity (Erroneous) Major/Hazardous

RNP AR APCH (RNP < 0.3 NM)

Continuity (Loss) Hazardous3

Integrity (Erroneous) Hazardous

1 In the RNP 1 navigation specification of the PBN Manual, the loss of function is classified as ‘minor’. Due to EASA’s decision to group all the basic requirements for lateral navigation together in Subsection 2 and not to grant specific approval for each separate navigation specification, but for the entire bundle, the failure condition has been set to ‘major’. Applicants that intend to apply for RNP 1 approval only with an intended classification of the loss of function as ‘minor’ are encouraged to consult EASA as early in the process as possible to discuss the applicable certification criteria.

2 The loss of function during the missed approach may be classified as a ‘minor’ failure condition and the integrity may be ‘major’.

3 The loss of VNAV during the final approach may be classified as a ‘minor’ failure condition, provided that lateral navigation is not affected.

Appendix B — INS/IRU standard performance and functionality (1) Introduction

Appendix B provides the performance and functionality criteria that an airborne INS/IRU position source should meet to support PBN operations.

(2) INS/IRU position source standard performance and functionality

(a) The equipment should support an unambiguous indication when its outputs are invalid.

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 108 of 270

(b) The navigation function of the equipment should be designed commensurate with a ‘major’ failure condition.

(c) The alignment, updating, and navigation computer functions of the system must not be invalidated by normal aircraft power transients.

(d) The equipment should provide or support the following functions and displays:

(i) valid ground alignment capability at all latitudes appropriate for the intended use of the installation;

(ii) a display of alignment status; and

(iii) the present position of the aeroplane in suitable coordinates.

(e) The circular error of the equipment should be lower than or equal to 2 nautical miles per flight hour on a 95-per-cent basis.

Appendix C — Installation and testing guidance (1) Introduction

(a) Appendix C provides guidance on the installation and testing of RNP Systems. Depending on the applicable airworthiness standards, the applicant should consider the following paragraphs as indicated below:

(i) Paragraphs (2), (3), and (4) of Appendix C should always be considered.

(ii) When Subsection 3 ‘Supplementary specifications for lateral navigation in final approach’ is applicable, paragraph (5) ‘Supplementary testing for lateral navigation in final approach’ of Appendix C should be considered.

(iii) When Subsection 4 ‘Supplementary specifications for vertical navigation’ is applicable, paragraph (6) ‘Supplementary testing for vertical navigation’ of Appendix C should be considered.

(iv) When Subsection 5 ‘Supplementary specifications for vertical navigation in final approach’ is applicable, paragraph (7) ‘Supplementary testing for vertical navigation in final approach’ of Appendix C should be considered.

(v) When Subsection 7 ‘Supplementary specifications for applications for advanced RNP’ is applicable, paragraph (8) ‘Supplementary testing for applications for advanced RNP’ of Appendix C, as well as Appendix D ‘RF leg demonstration templates’, should be considered.

(2) Equipment installation

(a) The applicant should can use equipment that has been granted ETSO authorisation and, in that case, should strictly follow the equipment manufacturer installation guide.

(b) For each of the equipment installed, the applicant should verify and assess all switching and transfer functions, including electrical bus switching and failure modes under partial or complete loss of electrical power, loss of signal reception, loss of equipment interfaced with the RNP system, etc. Under such failure conditions, the applicant should:

(i) evaluate the aircraft’s system response to ensure that the switch is accomplished as expected;

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 109 of 270

(ii) verify that the switch is clearly enunciated and that any warning associated with the loss of equipment is commensurate with the requirements of CS XX.1322; and

(iii) verify that the switching itself does not induce any inaccurate guidance and that the autopilot/flight director response is appropriate.

(c) For a multi-sensor installation, under sensor failure conditions, the applicant should verify the following:

(i) that the GNSS is used as a primary source of navigation;

(ii) the transfer to an alternative navigation sensor and the appropriate switching mode and annunciation are made;

(iii) that the switch is clearly enunciated and that any warning associated with the loss of equipment is commensurate with the requirements of CS XX.1322;

(iv) that the switching itself does not induce any inaccurate guidance and that the autopilot/flight director response is appropriate; and

(v) that the remaining navigation sensors are appropriately reflected in the positioning computation of the RNP system.

(d) During simulated loss of the GNSS signal-in-space, the applicant should verify that the criteria of point (2)(c)(ii) to (2)(c)(v) are met.

(e) Initial certification of systems, including multiple (scanning) DME sensors that have not been previously certified, must be based upon a demonstration of system accuracy by recording (at intervals not greater than 15 minutes) the DME/DME sensor position and comparing it to the actual position during evaluation flights. The latest revisions of FAA AC 25-7D and FAA AC 23-8C provide guidance on test distances from VOR and DME navigation aids. Recorded data should include sufficient signal parameters and sensor performance data to provide a clear indication of satisfactory sensor performance. The applicant should select the particular flight paths based on an analysis of critical signal characteristics, station geometry, signal coverage (including limited station availability with acceptable range), aircraft movement, etc. The system should demonstrate its ability to detect poor signal conditions, inadequate navigation capability, recovery from in-flight power failure, etc. The applicant should review and test the auto-tune logic to verify that ground stations are identified and tuned correctly.

(f) Inertial systems that satisfy the criteria of Appendix B do not need further evaluation.

(g) With regard to GNSS sensors that have been granted an ETSO authorisation against ETSO-C146 (Class Gamma equipment), it is stipulated that the equipment will support installations with the ability to compensate for the navigation centre to antenna offset. If applicable, the applicant should confirm that the antenna to aircraft centre of navigation offset is appropriate to the installation for GNSS SBAS equipment supporting RNP APCH to LPV and LNAV/VNAV minima.

Note: The fact that the GNSS antenna is top-mounted can result in several feet of vertical difference between the antenna and the aircraft centre of navigation, significantly greater than for ILS antennas. The centre-of-navigation to wheel-crossing height should be evaluated for each installation. For most installations, a fixed vertical offset is adequate.

(h) The applicant should evaluate the accessibility of all controls pertaining to the installation of the RNP System.

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 110 of 270

(i) The applicant should evaluate the visibility of display(s) and annunciator(s) pertaining to the installation of the RNP System during day and night lighting conditions. No distracting cockpit glare or reflections may be introduced.

(3) Sensor interference testing

(a) GNSS equipment is particularly susceptible to out-of-band SATCOM emissions and in- band inter-modulation between multiple channel SATCOM installations. The applicant should not install GNSS equipment on aircraft with SATCOM transceivers, unless absence of interference with the GNSS sensor is demonstrated.

(b) Improperly used or installed GNSS re-radiators can present misleading information to GNSS equipment. Equipment manufacturers may provide mitigation against the use of erroneous data for GNSS position and navigation solutions. Possible measures include: implementing or enabling cross-checks of GNSS sensor data against independent position sources and/or other detection monitors using GNSS signal metrics or data. It is left to the applicant to determine that the method chosen by the equipment manufacturer is adequate for the aircraft integration.

(c) The applicant should demonstrate the lack of interference from VHF radios on the completed installation of navigation sensors (GNSS, DME where applicable, etc.) by tuning each VHF transmitter to the frequencies listed below and transmitting for a period of 30 seconds while observing the signal status of each satellite being received. Degradation of individually received satellite signals below a point where the satellite is no longer available will require additional isolation measures to be taken:

(i) 121.150 MHz; 121.175 MHz; 121.200 MHz; 131.250 MHz; 131.275 MHz; and 131.300 MHz (for radios with 25-kHz channel spacing); and

(ii) 121.185 MHz; 121.190 MHz; 130.285 MHz and 131.290 MHz (for radios with 8.33- kHz channel spacing);

(d) For installations on rotorcraft, the applicant should ensure that the rotor blades do not interfere with the received signals. This problem has been experienced in some rotorcraft and varies with the rotation rate.

(4) Generic testing for performance-based lateral navigation

(a) The applicant should evaluate the navigation parameters displayed on cockpit instruments (such as HSI, CDI, distance display, electronic flight instrument system, moving maps, FMSs, etc.) against the relevant criteria. In particular, the parameters displayed should be consistent across the cockpit, especially the aircraft heading or track reference (magnetic or true), the aircraft altitude (feet or metres), and the aircraft speed (knots or km/h).

(b) The applicant should verify that the RNP system continuously provides to the flight crew:

(i) an estimation of the present position, the position accuracy and integrity;

(ii) the computed desired path and the deviation from that path; in particular, the applicant should:

(1) evaluate the sensitivity of the deviation display;

(2) verify that the full-scale setting is appropriate for the intended operation; and

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 111 of 270

(3) when applicable, verify that when the full-scale setting changes, the display of the updated deviation is appropriate;

(iii) the identification of the active TO waypoint;

(iv) the distance, bearing and time to the active TO waypoint; and

(v) the aircraft ground speed.

This behaviour should be evaluated for different flight phases, altitudes, and under various normal aircraft manoeuvres (e.g. bank angles of up to 30 degrees and pitch angles associated with take-off, departures, approaches, landing, and missed approaches, as applicable).

(c) The applicant should verify that the course selector and the RNP system are properly integrated. The behaviour of the system and the display of the aircraft heading and the selected course should be appropriate and consistent when the aircraft follows the RNP system’s flight plan but also when the aircraft is manually flown.

(d) The applicant should verify the automatic and manual selection/deselection of sensor types and positioning aids, in particular:

(i) The appropriate automatic sensor selection should be verified, and, where a multi- sensor system is installed, the applicant should check that the automatic selection is consistent with GNSS being the primary source of horizontal position;

(ii) Where a multi-sensor system is installed, the applicant should verify the appropriate automatic reversion when one or several sensors fail;

(iii) The applicant should verify the appropriate automatic selection and tuning of positioning navigation aids. Where DME is installed, the automatic selection and tuning should be evaluated where multiple DME can be received from the aircraft, for different flight phases and different altitudes. For each sensor, the applicant should verify the continuous aircraft position estimations for different flight phases, altitudes, and various normal aircraft manoeuvring (e.g. bank angles of up to 30 degrees and pitch angles associated with take-off, departures, approaches, landing and missed approaches as applicable);

(iv) The applicant should check the capability to manually override the selection or deselection of a positioning sensor type and positioning navigation aids.

(e) The applicant should verify the capability to create, review, modify and activate a flight plan. In particular, the applicant should verify the capability to extract and load procedures from the navigation database into the RNP system. During the extraction, all procedures’ characteristics (sequence of waypoints, speed and/or altitude constraint, etc.) should be loaded into the flight plan.

(f) The applicant should evaluate the following aspects when the RNP system is interfaced with an autopilot and/or a flight director. If some issues are raised, the RNP system may still be installed, but either should not be connected to the autopilot or have an appropriate aircraft flight manual supplement/rotorcraft flight manual supplement (AFMS/RFMS) limitation that mitigates the issue.

(i) The applicant should evaluate the steering response while the flight director and/or autopilot are/is coupled to the RNP system during a variety of different track and mode changes while operating at the maximum and minimum operating speeds. This evaluation should include, as applicable:

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 112 of 270

(1) transition from en route through the approach to missed approach modes and then back to en route;

(2) intercept and track to and from a waypoint on a selected course.

(ii) The applicant should evaluate:

(1) the steering response during the automatic sequencing of various flight plan legs and transition; and

(2) the appropriate display of this sequencing to the flight crew.

In particular, the capability to execute fly-by, fly-over, and RNAV holding should be evaluated for different altitudes, wind conditions, aircraft speeds, and configurations.

(iii) The applicant should verify that the lateral manoeuvre anticipation supplied by the RNP system is appropriate for the aircraft type. The applicant should verify that an appropriate annunciation of impending waypoint crossing is provided.

(iv) The applicant should verify that execution of the ‘direct-to’ and ‘direct-to’ with intercept function with a resultant aircraft heading change do not overshoot and do not cause ‘S-turns’.

(v) The applicant should evaluate that the autopilot response to the RNP system fault by simulating a representative fault consistent with the equipment architecture (e.g. pulling the circuit breaker). This test should be done under various navigation modes.

(vi) The applicant should verify that modification of the flight plan does not impact on the aircraft guidance until the flight plan and its modification is activated. This behaviour should be evaluated for various kinds of flight plan modifications (lateral revision, constraint insertion/deletion, etc.) and for different procedure types (departure procedures, en route, manually inserted segment, arrival procedures, etc.).

(g) The applicant should verify that the flight technical error (FTE) does not exceed the FTE credits. This test may not be necessary if the FTE has been previously established for the aircraft concerned. One acceptable way of assessing FTE is to monitor the measured cross-track deviation while either flying under autopilot control or flying manually using the navigation display provided.

(h) Tests should verify proper operation of caution indications and lateral navigation interface.

(i) Normal flight manoeuvres should not cause loss-of-system sensor inputs and the system dynamic response should be confirmed.

(j) The applicant should validate the navigational accuracy of multi-sensor equipment in each operating mode. In addition to overall system navigation performance, particular test requirements for navigational accuracy will vary depending on the particular sensors integrated in the multi-sensor equipment and whether sensor accuracy performance data has previously been obtained. The performance of each navigation sensor should be evaluated separately and in combination with other sensors as applicable.

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 113 of 270

(5) Supplementary testing for lateral navigation in final approach

(a) For installations where the autopilot has not been modified and the RNP system provides ILS-like deviations, the applicant should conduct several approaches:

(i) while flying raw data, flight director, and coupled to the autopilot, as applicable;

(ii) while intercepting before and after the final approach fix (FAF),

and check that the autopilot response is appropriate and that the displays are appropriate and consistent within the cockpit.

The objective of this test is not to verify approach performance but to ensure that the RNP system interfaces are compatible with the aircraft. In addition, the autopilot approach functionality should be evaluated to ensure compatibility with the ‘gain scheduling’ employed by some autopilots during approaches.

(b) For installations where the autopilot has been modified, the autopilot lateral control channel performance has not been assessed, or non-standard deviations are provided (not ILS-like), the approach performance will need to be evaluated by the applicant as per the latest revision of, AMC1 to CS 25.1329, FAA AC 23-17C or FAA AC 29-2C.

(c) For manual control to the approach flight path, the applicant should demonstrate that the appropriate flight display(s) provide(s) sufficient information to maintain the approach path and align with the runway or go-around without excessive reference to other cockpit displays.

(d) In order to ensure the system operates properly, the applicant should evaluate the lateral full-scale deflection while on approach.

(e) The applicant should evaluate how distance to go, course, bearing, etc., are displayed on all flight deck presentations during approach procedures when step-down fixes are included in the navigation database.

(6) Supplementary testing for vertical navigation

(a) The applicant should evaluate the autopilot response to the insertion of various altitude constraints into the RNP system’s flight plan:

(i) ‘AT or BELOW’ altitude constraint;

(ii) ‘AT or ABOVE’ altitude constraint;

(iii) ‘AT’ altitude constraint;

(iv) ‘WINDOW’ altitude constraint.

The autopilot response should be evaluated under various conditions (different aircraft configurations and speeds, different lateral paths, and transitions at the altitude constraint, etc.).

(7) Supplementary testing for vertical navigation in final approach

(a) For installations where the autopilot has not been modified and the RNP System provides ILS-like deviations, the applicant should conduct several approaches:

(i) while flying raw data, flight director and coupled to the autopilot, as applicable;

(ii) while intercepting before and after the final approach fix (FAF),

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 114 of 270

and check that the autopilot response is appropriate and that the displays are appropriate and consistent within the cockpit.

The objective of this test is not to verify approach performance, but to ensure that the RNP system interfaces are compatible with the aircraft. In addition, the autopilot approach functionality should be evaluated to ensure compatibility with the ‘gain scheduling’ employed by some autopilots during approaches. For example, some autopilots depend upon a radio altimeter or middle marker beacon passage inputs to enable a ‘glideslope extension’ function to reduce oscillating or aerodynamic instability when coupled to a glideslope signal during the final approach phase. As PBN approaches do not have middle marker beacons, the autopilot response needs to be evaluated when incorporating the PBN capability.

(b) For installations where the autopilot has been modified, the autopilot lateral control channel performance has not been assessed, or non-standard deviations are provided (not ILS-like), then the approach performance will need to be evaluated by the applicant as per the latest revision of AMC1 to CS 25.1329, Appendix B of CS-29, FAA AC 23-17b or equivalent means.

(c) For manual control to the approach flight path, the applicant should demonstrate that the appropriate flight display(s) provide(s) sufficient information to maintain the approach path and align with the runway or go-around without excessive reference to other cockpit displays.

(d) In order to ensure that the system operates properly, the applicant should evaluate the vertical full-scale deflection while on approach.

(e) A flight crew workload analysis when operating the RNP system in association with other piloting requirements should be conducted by the applicant during all phases of flight and found to be acceptable, including those non-normal procedures that can be evaluated in flight.

(f) Where the RNP System is capable of automatically intercepting a vertical path, the vertical fly-by and the autopilot response (if applicable) should be evaluated under different configurations and winds.

(g) If the equipment uses barometric input, the applicant should verify that the equipment properly interprets the barometer reading. Special consideration should be given to manually entering barometric corrections.

(h) The initial certification of each BARO-VNAV system to be used for IFR approach operations should be based on a system-performance demonstration by recording the BARO-VNAV equipment vertical guidance and comparing it to the actual aircraft position along a pre-established vertical flight path. This evaluation can be made by using the actual coded path and appropriate path definition.

(i) Data should be gathered using a variety of descent rates, angles, and lateral navigation source inputs available to the BARO-VNAV system.

Note: GNSS SBAS LNAV/VNAV most closely emulates BARO-VNAV performance.

(j) When a Class A TAWS is installed and LPV minima are foreseen to be used, the applicant should verify the interface between the TAWS and the RNP system by checking the excessive downward deviation from the glide path.

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 115 of 270

(k) When temperature compensation is enabled, the applicant should ensure that the display of corrected altitude(s) is consistent on all displays in the cockpit.

(l) Where the RNP system provides both Barometric VNAV and SBAS/GNSS VNAV, the applicant should ensure that transitions from one source to the other do not result in transients or jumps that would cause either a sudden change in aircraft position on the flight path or in commands that could contribute to destabilisation of the aircraft.

(8) Supplementary testing for applications for advanced RNP

(a) The applicant should evaluate the aircraft response to the insertion of a hold to a manual termination. This evaluation should be performed at different altitudes, under different wind conditions, and for different aircraft operating speeds.

(b) RF legs should be evaluated as detailed in Appendix D.

(c) The use of different navigation accuracies (RNP values) between 0.3 and 1 NM should be evaluated. The applicant should particularly evaluate the aircraft response to navigation accuracy changes and should check that:

(i) the display update following the navigation accuracy change is appropriate;

(ii) the display of the updated navigation accuracy is consistent with all displays in the cockpit; and

(iii) the steering response while the flight director and/or autopilot are/is coupled to the RNP system during the navigation accuracy change is appropriate.

Appendix D — RF leg demonstration templates AppD-1 — Introduction

(1) Applicants must demonstrate the aircraft’s capability to perform all types of RF legs that can be published on instrument procedures as per the procedure design criteria. Appendix D provides templates that are an acceptable method to demonstrate an aircraft’s capability to perform RF legs. Applicants may use engineering simulations and/or aircraft for the flight test demonstrations. The templates depict the various RF legs that procedure designers may use when constructing actual initial, intermediate, missed approach, or final approach segments for RNP approaches along with SIDs and STARs. Applicants may use the templates to create one or more approach procedures at the desired aerodrome for flight test demonstration purposes in visual meteorological conditions only. The intent of such demonstrations is to streamline the airworthiness approval for conducting RF legs.

(2) The demonstration procedures need to include the depicted RF leg types shown in AppD-2. To increase flight test efficiency, it is acceptable for applicants to link the individual RF legs that are depicted in the figures by using straight segments to create ‘mega procedures’ for demonstrating the aircraft’s capability. However, the reflex curve legs (‘S-turns’) and decreasing radius turns must not have a straight segment between the path terminators (see Figure 1 below for an example). The point is to demonstrate that the aircraft is capable of flying the various types of turns including turns of minimum radius.

Note: Figure 1 is only an example and is not intended as the only possible combination for creating efficient flight profiles.

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 116 of 270

Figure 1: Example procedure profiles

(3) It should be noted that the templates are designed for use on both RNP AR and standard RNP approach procedures with RF legs. In addition, the procedures created from the templates intend to provide some ‘stressing’ situations as a consequence of the procedure design criteria applied. For example, several RF leg radii were intentionally reduced to approach the 25-degree RNP AR flight guidance system bank angle limits, given the design wind criteria and aircraft approach category C/D in terms of aircraft speeds (121–165 knots).

(4) AppD-2 provides a basic description, illustration, and waypoint information for the RF legs. A ‘test guide’ in AppD-3 lists a recommended testing regimen and considerations for test conduct, but the applicant can tailor the test regimen as needed.

(5) The test procedures are designed for an aerodrome with an elevation of approximately 1 500 ft MSL. All turn radii were computed using expected ground speeds and altitudes based upon the 1 500-ft MSL aerodrome elevation. The turn radii were adjusted so that the required bank angle, given the adverse wind input, would approach the bank angle limitation noted in the procedure design criteria. The waypoint and navigation leg data is provided so that the procedures can be ‘translated’ to a location suitable to the applicant. However, the elevation of the selected location should be within the range of 1 000–2 000 ft MSL to ensure that the designed turn radii and bank angles do not change significantly. If the location used has an elevation outside the 1 000–2 000-ft MSL range, it is the applicant’s responsibility to ensure the procedures offer adequate obstacle clearance and meet the bank angle limits in the RF leg design criteria.

40 0 0

5200 5 4 0 0

56 0 0

44 0 0

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 117 of 270

AppD-2 — Description of test procedures

Each of the procedures is described in this section along with an image for illustration.

AppD-2.1 — Departures

(1) Design criteria for departures are currently being developed. Subsequently, two procedures were designed using known criteria in addition to criteria features that are likely to be incorporated. One of the procedures mimics a conventional design at Boston Logan International Airport that has proven difficult for some high-performance aircraft to use. Due to environmental restrictions on the ground track, the previous conventional procedure incorporates a series of short track-to-fix (TF) legs that, when viewed from a larger perspective, ‘looks’ like a series of RF legs when considering that each of the waypoints are ‘fly-by’. However, in the conventional format, some FMSs have difficulty with the short leg segments and, therefore, annunciate an inability to capture a subsequent leg. The resolution to this issue is the RF leg or a series of RF legs that ensure conformance to the desired ground path. The ‘Alpha departure’ shown in Figure 2 incorporates an RF leg shortly after take-off followed by a straight climbing segment to a series of two back-to-back RF legs with reducing radii. Waypoint information is shown in Table 1.

Figure 2: Alpha departure

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 118 of 270

Table 1: Alpha departure waypoints

(2) The ‘Bravo departure’ shown in Figure 3 consists of an RF leg shortly after take-off followed by a brief straight segment, then two back-to-back RF legs with a turn direction reversal. The turn radii also vary as the aircraft climbs and increases performance. Waypoint information is shown in Table 2.

Figure 3: Bravo departure

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 119 of 270

Table 2: Bravo departure waypoints

AppD-2.2 — Arrival

(1) A single arrival was designed which is similar to a previously studied design at Fargo, North Dakota, USA. As the aircraft descends and decelerates, it follows a path that consists of a series of RF legs with a reversal of the turn direction after the first turn. The second directional turn consists of two back-to-back RF legs with decreasing radii. The arrival is shown in Figure 4 and waypoint information is shown in Table 3.

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 120 of 270

Figure 4: Arrival

Table 3: Arrival waypoints

AppC-2.3 — Approaches

(1) Three approaches are provided to assess avionics guidance capability through a series of RF leg approach designs. These templates are acceptable for demonstrating the aircraft’s capability to perform both RNP AR and standard RNP APCH approach procedures.

(2) As shown in Figure 5, Approach 1 is a teardrop procedure that incorporates a descending RF right turn to final, rolling out at the final approach fix. Note that there is no straight segment 2 NM prior to the final approach fix which will be stressing for RNP APCH final approach guidance due to the reduced scaling transition from terminal mode to approach mode. This path requires the aircraft to descend, decelerate, and then configure for landing all during the RF leg. The missed approach also contains an RF leg en route to the missed approach hold. Waypoint information is shown in Table 4 and vertical error budget information is shown in Table 5.

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 121 of 270

Figure 5: Approach 1

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 122 of 270

Table 4: Approach 1 waypoint information

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 123 of 270

Table 5: Approach 1 vertical error budget (VEB)

(3) Approach 2, as shown in Figure 6, is also a descending right turn to final but has a series of four RF legs with differing radii. Similar to Approach 1 in Figure 5, this path will require the aircraft to descend and decelerate during the RF leg. Waypoint information is shown in Table 6 and vertical error budget information is included in Table 7.

Figure 6: Approach 2

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 124 of 270

Table 6: Approach 2 waypoints

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 125 of 270

Table 7: Approach 2 vertical error budget (VEB)

(4) Approach 3 is shown in Figure 7. This procedure uses an RF leg early in the procedure followed by a brief straight segment, then two back-to-back RF legs with a turn direction reversal. The second RF leg terminates at the final approach fix. As on the other approaches, the aircraft will be required to descend, decelerate, and configure for landing during the series of RF legs. The missed approach also includes an RF leg to the missed approach hold. Waypoint information is shown in Table 8 and vertical error budget information is included in Table 9.

Figure 7: Approach 3

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 126 of 270

Table 8: Approach 3 waypoints

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 127 of 270

Table 9: Approach 3 vertical error budget (VEB)

AppD-3 — Test guide

(1) AppD-3 provides guidance that may be used to conduct development and/or airworthiness RF leg testing for new equipment hardware/software, or updates to existing equipment hardware/software. The guidance is designed to be used together with the templates described in AppD-2 to create .‘FOR TEST ONLY’ terminal area instrument procedures (departures, arrivals, and approaches). The intent of this regimen is to provide a set of rigorous instrument procedures that the applicant can use to demonstrate that the RF leg airworthiness approval criteria are met.

(2) The test instrument procedures are designed and located at an aerodrome with an elevation of approximately 1 500-ft MSL. The waypoint and navigation leg data is provided so that the procedures can be ‘translated’ to another location suitable to the applicant. However, the new aerodrome elevation should be within the range of 1 000–2 000-ft MSL to ensure that the designed turn radii and bank angles do not change significantly (see AppD-1). The applicant will be required to obtain a navigation database for their respective navigation system that contains the test procedures.

(3) The information in the following paragraphs describes test conditions such as generic aircraft performance parameters, desired atmospheric conditions, and considerations to assist the applicant with creating a detailed test plan. Applicants are encouraged to use these recommended guidelines. However, amendments may be made as required to accommodate unique equipment designs, test environment, testing methods, or other considerations.

AppD-3.1 — Initial set-up

(1) Configure the aircraft for individual trials using two gross weight conditions:

(a) nominal heavy weight resulting in lower accelerations to climb speed and higher speeds on approach;

(b) nominal light weight resulting in higher accelerations to climb speed and lower speeds on approach.

(2) The test should be performed in representative operational conditions in terms of speeds, flap, and gear settings, etc.

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 128 of 270

(3) Verify that a navigation database with the ‘FOR TEST ONLY’ terminal procedures is loaded in the RNP system.

(4) Verify that desired data parameters will be recorded (if data recording capability is available).

Note: In addition to the desired data parameters, the lateral path definition (desired path) and lateral path ‘cross-track error’ (distance from the path’s centre line) should be included in the recorded data parameters to monitor/review path maintenance performance.

(5) Configure the simulation, if practical, for trials using two atmospheric conditions:

(a) standard day, with standard lapse rate;

(b) 35 °C outside air temperature, with standard lapse rate.

(6) If practical, simulated wind direction should be set to a tailwind for each turn entry. Below 2 000-ft AGL, the wind velocity should be fixed at 30 kt. At 2 000-ft AGL and above, the wind velocity in knots (VKTW) should be calculated as a function of the altitude in feet (A) in accordance with the formula:

= 0.00198 × + 47

If impractical (i.e. when the simulator cannot model variable winds and various levels), select the wind direction and velocity that most effectively simulates the worst-case tailwind for the procedure.

AppD-3.2 — Airborne test conditions

(1) Record aircraft configuration:

(a) verify that the simulation is ‘conformed’ with correct avionics hardware and software;

(b) record aircraft performance parameters (gross weight, etc.);

(c) record aircraft configuration and changes to the configuration (flap, gear, and thrust setting, etc.).

(2) Select the procedure to be tested, load the procedure into the route of flight, and verify the procedure is in the active route.

(3) Ensure the correct RNP values correspond to the appropriate value for the respective route/procedure segment.

(4) Engage lateral and vertical path guidance where applicable.

(5) Engage autopilot/flight director (as soon as practical after take-off) and verify the autopilot/flight director is providing guidance to the lateral path.

(6) Fly the programmed route and observe that the lateral cross-track deviation does not exceed the FTE for the respective RNP level as follows:

RNP FTE

1.0 0.5 NM

0.3 0.25 NM with flight director / 0.125 NM with autopilot

< 0.3 Agreed allowable FTE value to achieve TSE ≤ 1 × RNP value

Table 10: FTE value versus RNP value

CS-ACNS Issue 5 Subpart C — Navigation (NAV)

SECTION 1 – PERFORMANCE-BASED NAVIGATION (PBN)

Annex to EDD 2024/003/R Page 129 of 270

(7) Perform steps (1) through (6) for each appropriate aircraft gross weight configuration and for each test procedure.

CS-ACNS Issue 5 Subpart D — Surveillance (SUR)

Section 1 – Mode A/C only surveillance

Annex to EDD 2024/003/R Page 130 of 270

SUBPART D — SURVEILLANCE (SUR)

SECTION 1 – MODE A/C ONLY SURVEILLANCE

GENERAL

CS ACNS.D.AC.001 Applicability (See GM1 ACNS.D.AC.001)

This section provides standards for Mode A/C only airborne surveillance installations.

[Issue: CS-ACNS/4]

GM1 ACNS.D.AC.001 Applicability Background information on Mode A/C surveillance systems is provided in Appendix A – Background information on Mode A/C surveillance systems.

[Issue: CS-ACNS/4]

SYSTEM FUNCTIONAL REQUIREMENTS

CS ACNS.D.AC.010 Transponder characteristics (See AMC1 ACNS.D.AC.010)

(a) The transponder is approved and has Mode A and Mode C capability.

(b) The transponder replies with Mode A and Mode C replies to Mode A/C interrogations, to Mode A/C-only all-call interrogations, and to Mode A/C/S all-call interrogations.

(c) The peak pulse power available at the antenna end of the transmission line of the transponder is more than 125 W (21 dBW) and not more than 500 W (27 dBW) for aircraft that operate at altitudes exceeding 4 570m (15 000 ft) or with a maximum cruising speed exceeding 90 m/s (175 knots).

(d) The peak pulse power available at the antenna end of the transmission line of the transponder is more than 70 W (18.5 dBW) and not more than 500 W (27 dBW) for aircraft operating at or below 4 570m (15 000 ft) with a maximum cruising airspeed of 90 m/s (175 knots) or less.

AMC1 ACNS.D.AC.010 Transponder characteristics (a) Transponder capabilities.

(1) To be approved, the Mode A/C only transponder should hold an EASA equipment authorisation in accordance with European Technical Standard Order ETSO-C74d, or an equivalent standard that is consistent with ICAO Annex 10 Volume IV, and which is acceptable to EASA.

CS-ACNS Issue 5 Subpart D — Surveillance (SUR)

Section 1 – Mode A/C only surveillance

Annex to EDD 2024/003/R Page 131 of 270

(2) The Mode A/C only transponder should be a class 2A / class 2B as defined in ETSO-C74d.

Note 1: ETSO-C74d Class 2 equipment meets EUROCAE Document 1/WG9 /71 June 1972 with amendment 1 and 2. Amendment 2 contains the requirements and tests to show that the transponder correctly replies to Mode A/C-only all call interrogations and to Mode A/C/S all-call interrogations used by Mode S radars.

Note 2: RTCA DO-144 does not include requirement to reply to Mode A/C/S All-Call and Mode A/C-Only All-Call interrogations and is, therefore, not sufficient to prove the compliance. RTCA DO-144A contains the requirements for the equipment to reply to Mode A/C/S All-Call and Mode A/C-Only All-Call interrogations.

(b) Minimum reply rate

(1) Mode A/C only transponders should be capable of continuously generating at least 500 replies per second for a 15-pulse coded reply.

(2) Transponder installations used solely below 4 500 m (15 000 ft), or below a lesser altitude established by the appropriate authority or by regional air navigation agreement, and in aircraft with a maximum cruising true airspeed not exceeding 90 m/s (175 knots) should be capable of generating at least 1 000 15-pulse coded replies per second for a duration of 0,1 s.

Note: The rate of 1 000 replies per second for a limited duration of 100ms is an acceptable deviation to ETSO-C74d.

(3) Transponder installations operated above 4 500 m (15 000 ft) or in aircraft with a maximum cruising true airspeed in excess of 90 m/s (175 knots) should be capable of generating at least 1 200 15-pulse coded replies per second for a duration of 0,1 s.

Note 1: A 15-pulse reply includes 2 framing pulses, 12 information pulses, and the SPI pulse.

Note 2: The transponder should be capable of replying to this short-term burst rate, even though the transponder may not be capable of sustaining this rate.

Note 3: The rate of 1 200 replies per second for a limited duration of 0,1 s is an acceptable deviation to ETSO-C74d.

(c) Minimum output power level

The transponder power output capability should be verified as follows depending on the aircraft capability:

(1) For aircraft that operate at altitudes exceeding 4 570 m (15 000 ft) or with maximum cruising speed exceeding 90 m/s (175 knots), the class of the transponder declared in the transponder DDP should be Class A.

(2) For aircraft operating at or below 4 570m (15 000 ft) with a maximum cruising airspeed of 90 m/s (175 knots) or less, the class of the transponder declared in the transponder DDP should be Class A or Class B.

CS ACNS.D.AC.015 Data transmission (See AMC1 ACNS.D.AC.015)

The surveillance system provides the following data in the replies:

(a) The Mode A identity code in the range 0000 to 7777 (Octal).

CS-ACNS Issue 5 Subpart D — Surveillance (SUR)

Section 1 – Mode A/C only surveillance

Annex to EDD 2024/003/R Page 132 of 270

(b) The pressure altitude corresponding to within plus or minus 38.1 m (125 ft), on a 95 % probability basis, with the pressure-altitude information (referenced to the standard pressure setting of 1.01325 105 Pa),used on board the aircraft to adhere to the assigned flight profile. The pressure altitude ranges from minus 304 m (1 000 ft) to the maximum certificated altitude of aircraft plus 1520 m (5 000 ft).

(c) Special Position Indication (SPI) for 15 to 30 seconds after an IDENT (SPI) command has been initiated by the pilot.

AMC1 ACNS.D.AC.015 Data transmission (a) Mode A Code verifications.

(1) Set the Mode A code to 7776 (or other Mode A code agreed with the local Air Traffic Control Unit) through the dedicated flight crew interface. Confirm receipt of correct code by using ground test equipment.

(2) For dual transponder installation with a common control panel, set the Mode A code to 7776 (or other Mode A code agreed with the local Air Traffic Control Unit) and verify that the correct code is received by the ground test equipment. Switch to transponder 2 and verify that the correct Mode A code is received by the ground test equipment.

Note: Agreement of Mode A code values is to be agreed with the local ATC if the transponder is in the visibility of an ATC cooperative surveillance system.

(b) Pressure Altitude verifications

(1) Verify that all Mode A/C transponders report the pressure-altitude encoded in the information pulses in Mode C replies.

Note: more details on the encoding of the altitude can be found in ICAO Annex 10, Vol IV, para 3.1.2.6.5.4.

(2) Select the altitude switch to the ON position and verify that the transponder provides the current aircraft altitude in response to Mode C interrogations.

(3) A sufficient number of test points should be checked to ensure that the altitude reporting equipment and transponder perform their intended function through their entire range while ascending or descending. Where a Gillham altitude encoder is used, tests of each altitude code segment of the encoder (2300, 2500, 3800, 4300, 4800, 6800, 14800 30800, 70800, 90800, 110800 and 126700 if available) should be sufficient to ensure proper operation of each altitude code segment of the encoder.

CS ACNS.D.AC.020 Altitude source (See AMC1 ACNS.D.AC.020)

(a) The reported pressure altitude is obtained from an approved source.

(b) The altitude resolution is equal to or less than 30.48 m (100 ft.).

(c) The altitude source connected to the active transponder is the source being used to fly the aircraft.

CS-ACNS Issue 5 Subpart D — Surveillance (SUR)

Section 1 – Mode A/C only surveillance

Annex to EDD 2024/003/R Page 133 of 270

AMC1 ACNS.D.AC.020 Altitude source (a) Altimeters compliant with JAA TGL No 6 are an approved and acceptable means of compliance

for the altitude source.

(b) Altimeters with a pressure altitude resolution lower than or equal to 7,62 m (25 ft) is an approved and acceptable means of compliance.

Note: Altitude source resolution of 7,62 m (25 ft) or better is required for aeroplanes intended to be used for international air transport as defined in ICAO Annex 6 Part 1 — 6.19.

(c) An altimeter with a pressure altitude resolution lower than or equal to 30 m (100 ft) and greater than 7.62 m (25 ft) is an approved and acceptable means of compliance for aircraft provided that the flight deck interface provides a means to inhibit the transmission of pressure altitude information for aircraft equipped with Gillham encoded altitude

Note: It is not recommended to install altimeters with a Gillham altitude encoder interface.

(d) Manual or automatic selection of the altitude source are acceptable means of compliance

CS ACNS.D.AC.025 Flight deck interface (See AMC1 ACNS.D.AC.025)

A means is provided to:

(a) select Mode A Code including emergency indicators;

(b) initiate the IDENT (SPI) feature;

(c) notify the flight crew when the transmission of pressure altitude information has been inhibited if a means to inhibit the transmission of pressure altitude is provided;

(d) select the transponder to the ‘standby’ or ‘OFF’ condition;

(e) indicate the non-operational status or failure of the transponder system without undue delay and without the need for flight crew action;

(f) display the selected Mode A code to the flight crew; and

(g) select the pressure altitude source to be connected to the active transponder.

AMC1 ACNS.D.AC.025 Flight deck interface Modes of operation should be identified. Attention should be closely paid to line select keys, touch screens or cursor controlled trackballs as these can be susceptible to unintended mode selection resulting from their location in the flight deck.

Note: Systems not utilising Gillham interfaces may or may not provide a means to inhibit the transmission of pressure altitude.

SYSTEM PERFORMANCE REQUIREMENTS

CS ACNS.D.AC.030 Integrity The Mode A/C only airborne surveillance system integrity is designed commensurate with a ‘minor’ failure condition .

CS-ACNS Issue 5 Subpart D — Surveillance (SUR)

Section 1 – Mode A/C only surveillance

Annex to EDD 2024/003/R Page 134 of 270

CS ACNS.D.AC.035 Continuity The Mode A/C airborne surveillance system continuity is designed to an allowable qualitative probability of ‘probable’.

INSTALLATION REQUIREMENTS

CS ACNS.D.AC.040 Dual/multiple transponder installation (See AMC1 ACNS.D.AC.040)

If more than one transponder is installed, simultaneous operation of the transponders is prevented.

[Issue: CS-ACNS/4]

AMC1 ACNS.D.AC.040 Dual/multiple transponder installation When dual or multiple transponders are installed on an aircraft, it is highly recommended to use a common control interface/panel to ensure that only one transponder is active at a given time.

[Issue: CS-ACNS/4]

CS ACNS.D.AC.045 Antenna installation (See AMC1 ACNS.D.AC.045)

The installed antenna(s) has (have) a radiation pattern which is vertically polarised, omnidirectional in the horizontal plane, and has sufficient vertical beam width to ensure proper system operation during normal aircraft manoeuvres.

AMC1 ACNS.D.AC.045 Antenna Installation (a) Antenna locations recommended by the aircraft manufacturer do not need to be revalidated.

(b) Antenna performance for new locations may be validated in flight, by ground measurements or simulation modelling.

CS-ACNS Issue 5 Subpart D — Surveillance (SUR)

Section 2 – Mode S elementary surveillance

Annex to EDD 2024/003/R Page 135 of 270

SECTION 2 – MODE S ELEMENTARY SURVEILLANCE

GENERAL

CS ACNS.D.ELS.001 Applicability (See AMC1 ACNS.D.ELS.001)

This section provides the standards for airborne Mode S Elementary Surveillance installations.

AMC1 ACNS.D.ELS.001 Applicability Background information on Mode S ELS systems is provided in Appendix B – Background information on Mode S ELS.

Provided that the differences listed in Appendix D – Differences between CS ACNS.D.ELS and JAA TGL 13 Rev1 have also been addressed, then previous declarations of compliance with JAA TGL 13 Revision 1 (Certification of Mode S Transponder Systems for Elementary Surveillance), supplemented with the additional assessments, are also acceptable means of compliance.

Note: A list of Mode S ELS-related documents is provided in Subpart D, Appendix B, Section (b).

[Issue: CS-ACNS/4]

SYSTEM FUNCTIONAL REQUIREMENTS

CS ACNS.D.ELS.010 Transponder characteristics (See AMC1 ACNS.D.ELS.010)

(a) The transponder(s) is (are) an approved level 2 or greater Mode S transponder(s) with Elementary Surveillance and Surveillance Identifier (SI) capability.

(b) The transponder(s) of aircraft that have ACAS II installed is (are) ACAS compatible

(c) The peak pulse power available at the antenna end of the transmission line of the transponder is more than 125 W (21 dBW) and not more than 500 W (27 dBW) for aircraft that operate at altitudes exceeding 4 570 m (15 000 ft) or with a maximum cruising speed exceeding 90 m/s (175 knots).

(d) The peak pulse power available at the antenna end of the transmission line of the transponder is more than 70 W (18.5 dBW) and not more than 500 W (27 dBW) for aircraft operating at or below 4 570 m (15 000 ft) with a maximum cruising airspeed of 90 m/s (175 knots) or less.

AMC1 ACNS.D.ELS.010 Transponder characteristics (a) Transponder capabilities

(1) To be approved, the Mode S transponder should hold an EASA equipment authorisation in accordance with European Technical Standard Order ETSO-C112d, or an equivalent standard that is consistent with ICAO Annex 10 Volume IV and which is acceptable to the responsible certification authority.

Note: ETSO-C112d requires compliance with EUROCAE ED-73E.

CS-ACNS Issue 5 Subpart D — Surveillance (SUR)

Section 2 – Mode S elementary surveillance

Annex to EDD 2024/003/R Page 136 of 270

(2) The transponder class can be verified by checking that the transponder DDP declares the transponder level as ‘2’, ‘3’, ‘4’, or ‘5’.

Note: The definition of a level 2 transponder and associated functions can be found in EUROCAE ED-73E paragraph 1.4.2.1, 3.22 and 3.23.

(3) The SI code capability can be verified by checking that the transponder DDP indicates the letter ‘s’ in the transponder capability declaration.

Note 1: The DDP indicates those requirements of ED-73E (or later version) with which the transponder is not compliant with.

Note 2: The transponder SI code capability can be found in EUROCAE ED-73E paragraph 3.18.4.34. SI codes have been allocated to Mode S radars used in Europe and it is, therefore, an important capability to ensure correct detection of the aircraft.

(4) The Elementary Surveillance functionality can be verified by checking that the transponder DDP indicates the letter ‘l’ for ELS or ‘n’ for EHS in the transponder capability declaration.

Note: Such transponders meet the requirements specified in EUROCAE ED-73E 3.29. According to ED-73E, a transponder with the Enhanced Surveillance capability has also the Elementary Surveillance capability.

(5) ACAS compatibility can be verified by checking that the transponder DDP indicates the letter ‘a’ in the transponder capability declaration.

Note: Necessary capabilities to be an ACAS-compatible Mode S transponder are described in section 3.27 of EUROCAE ED-73E.

(b) Minimum output power level: The transponder power output capability should be verified as follows, depending on the aircraft capability:

(1) For aircraft that operate at altitudes exceeding 4 570m (15 000ft) or with maximum cruising speed exceeding 90 m/s (175 knots), the class of the transponder declared in the transponder DDP should be Class 1.

(2) For aircraft operating at or below 4570m (15 000ft) with a maximum cruising airspeed of 90 m/s (175 knots) or less, the class of the transponder declared in the transponder DDP should be Class 1 or Class 2.

Note: Classes of equipment are defined in EUROCAE ED-73E 1.4.2.4. Power characteristic is defined in ICAO Annex 10 Volume IV 3.1.1.7.11.

CS ACNS.D.ELS.015 Data transmission (See AMC1 ACNS.D.ELS.015)

(a) The surveillance system provides the following data in the Mode S replies:

(1) The Mode A Code in the range 0000 to 7777 (Octal);

(2) The pressure altitude corresponding to within plus or minus 38 m (125 ft), on a 95 per cent probability basis, with the pressure-altitude information (referenced to the standard pressure setting of 1013.25 hectopascals), used on board the aircraft to adhere to the assigned flight profile. The pressure altitude ranges from minus 300 m (1 000 ft) to the maximum certificated altitude of aircraft plus 1 500 m (5 000 ft);

(3) On-the-ground status information;

CS-ACNS Issue 5 Subpart D — Surveillance (SUR)

Section 2 – Mode S elementary surveillance

Annex to EDD 2024/003/R Page 137 of 270

(4) The Aircraft Identification as specified in Item 7 of the ICAO flight plan or the aircraft registration;

(5) Special Position Indication (SPI);

(6) Emergency status (Emergency, Radio communication failure, Unlawful interference);

(7) The data link capability report;

(8) The common usage GICB capability report;

(9) The ICAO 24-bit aircraft address; and

(10) Aircraft that have ACAS II installed provide the ACAS active resolution advisory report.

(b) All other data transmitted is verified.

(1) If the system transmits one or more additional downlink airborne parameters in addition to those listed in paragraph (a), then the relevant sub specifications of CS ACNS.D.EHS.015 are also complied with.

(2) If the system transmits additional parameters on the extended squitter and if their full compliance with CS ACNS.D.ADSB has not been verified, as a minimum the aircraft identification, pressure altitude, ICAO 24-bit aircraft address is identical to those transmitted in the Mode S replies. Additionally the position and velocity quality indicators reports the lowest quality.

AMC1 ACNS.D.ELS.015 Data transmission Data transmission verifications

(a) Table 1Error! Reference source not found. below provides the parameters that should be verified for Mode S elementary surveillance.

Table 1 — List of parameters to be verified on an ELS installation

Item Parameters Message/register Remark

1 Mode A code and Emergency status

DF5 and DF21 Note 3

2 Pressure altitude DF4 and DF20 See (b) and (c)

3 On-the-ground status CA field in DF11 or FS field in DF4/5/20/21

4 Aircraft Identification Register 2016 See (d)

5 SPI DF4/5/20/21 See (e)

6a Capability report CA field in DF11

6b Data-link capability report and common usage GICB capability report

Register 1016 Register 1716 (g)

7 ICAO 24 bit aircraft address DF11

8 RA report Register 3016 + announcement in DF4/5/20/21

Only for ACAS installation see (f)

Note 1: Information about how Mode S ELS data is used by Mode S ground systems can be found in Subpart D, Appendix B.

CS-ACNS Issue 5 Subpart D — Surveillance (SUR)

Section 2 – Mode S elementary surveillance

Annex to EDD 2024/003/R Page 138 of 270

Note 2: Downlink formats (DFs) are defined in ICAO Annex 10, Volume IV and EUROCAE ED-73E. A summary can also be found in Subpart D, Appendix B.

Note 3: It is not recommended to have 2 transponders installed without a common control panel.

(b) Pressure Altitude

(1) The consistency of the altitude reported in Mode C replies and Mode S replies should be checked.

Note: An incorrect installation of altimeters using Gillham encoding may result in altitude transmitted in Mode C replies and no altitude transmitted in Mode S replies.

(2) For aircraft transmitting parameters via the Extended Squitter, for which compliance with Subpart D section 4 is not required, the pressure altitude data should be checked in the Extended Squitter register for airborne position (register 0516).

(c) Pressure altitude resolution transmission

(1) The resolution of the transmitted pressure altitude should be 7.62 m (25 ft) for aircraft equipped with a pressure altitude source having a resolution better than 7.62 m (25 ft) for all altitudes except those above 15 298 m (50 187.5 ft).

(2) Aircraft equipped with altimeters that have a resolution greater than 7.62 m (25 ft) (e.g. 30.48 m (100 ft)) should report their altitude in 30.48 m (100 ft) encoding.

(3) Verify that the encoding of the altitude is appropriate to the altimeter resolution as defined in paragraphs 1 and 2 above.

(4) For aircraft transmitting parameters via the Extended Squitter, for which compliance with Subpart D section 4 is not required, the pressure altitude resolution data should be checked in the Extended Squitter register for airborne position (register 0516).

(d) Aircraft Identification

(1) For aircraft transmitting parameters via the Extended Squitter, for which compliance with Subpart D section 4 is not required, the Aircraft Identification received via the Extended Squitter should be checked to ensure that it is identical to the information transmitted in register 2016.

(e) Special Position Indication (SPI)

The FS field should report FS = 4 or 5 for 18 seconds (+/-1 second) in replies DF4, DF5, DF20 or DF21 after the SPI (IDENT) has been manually activated.

Note: Flight Status values can be found in ICAO Annex 10, Vol IV, paragraph 3.1.2.6.5.1.

(f) ACAS active Resolution Advisory report

For aircraft that have ACAS II installed, no undue RA report should be announced (DR field never set to 2, 3, 6 or 7) within (5 minutes).

(g) Common usage GICB capability report: BDS 1716 = 0 is an acceptable means of compliance for transponders that are strictly ELS (not transmitting other parameters).

(h) Transmission of other parameters

When one or more other airborne data items are transmitted, they should be verified as proposed in AMC1 ACNS.D.EHS.015.

CS-ACNS Issue 5 Subpart D — Surveillance (SUR)

Section 2 – Mode S elementary surveillance

Annex to EDD 2024/003/R Page 139 of 270

Note 1: The minimum data transmission verification of transponder also having ADS-B ES capabilities has been defined above. Transponders that are transmitting parameters other than the minimum tested above, are encouraged to demonstrate compliance with Subpart D section 4.

Note 2: The implementation of registers E316, E416, E516 and E616 is recommended.

[Issue: CS-ACNS/4]

CS ACNS.D.ELS.020 On-the-ground status determination (See AMC1 ACNS.D.ELS.020)

(a) The on-the-ground status is not set by a manual action.

(b) If automatic determination of the On-the-ground status is not available, the On-the-ground status is set to airborne.

AMC1 ACNS.D.ELS.020 On-the-ground status determination The automatic determination of the on-the-ground status should be obtained from:

(a) Weight On Wheel (WOW) sensor: When the aircraft is equipped with an automatic sensor to determine if the aircraft is on the ground (i.e. Weight On Wheel sensor), this sensor should be used as the on-the-ground status source of the transponder. For Aircraft with transponders that have access to at least one of the following parameters (ground speed, radio altitude, airspeed) the following validation check should be performed when detected ‘on the ground’ and the air/ground status should be overridden and changed to ‘airborne’ if [Ground speed > 50 m/s (100 knots) OR airspeed > 50 m/s (100 knots) OR radio altitude> 15 m (50 feet)].

Note: Care should be taken to ensure the wiring of the WOW to the correct transponder pins.

(b) automatic algorithm : If ground speed, radio altitude, or airspeed parameters are being used in the algorithm and the ‘on-the-ground’ condition is being reported or if the on-the-ground status has been commanded via the TCS subfield, the on-the-ground status is to be overridden and changed to ‘airborne’ if :

Ground Speed OR Airspeed > X or Radio height > 15 m (50 ft).

Note 1: Care should be taken to ensure that the chosen threshold values of X are such that the aircraft can never report ‘on ground’ status when in the air, and should be based on the aircraft nominal performance.

Note 2: Systems that support Enhanced Surveillance and ADS-B might use available airborne parameters in their automatic algorithm to determine if they are on the ground. More information can be found in Subpart D section 4.

CS ACNS.D.ELS.025 Altitude source (See AMC1 ACNS.D.ELS.025)

(a) The reported pressure altitude is obtained from an approved source.

(b) The altitude resolution is less than or equal to 30.48 m (100 ft.).

(c) The altitude source connected to the active transponder is consistent with the source being used to fly the aircraft.

CS-ACNS Issue 5 Subpart D — Surveillance (SUR)

Section 2 – Mode S elementary surveillance

Annex to EDD 2024/003/R Page 140 of 270

[Issue: CS-ACNS/4]

AMC1 ACNS.D.ELS.025 Altitude source (a) Compliance with JAA TGL No 6 is an approved acceptable means of compliance for an altimeter

as an altitude source.

(b) A pressure altitude resolution of less than or equal to 7.62 m (25 ft) is an approved acceptable means of compliance for an altimeter.

Note: An altitude source resolution of less than or equal to 7.62 m (25 ft) is required for aeroplanes intended to be used for international air transport, as defined in ICAO Annex 6, Part 1, Section 6.19.

(c) A pressure altitude resolution of less than or equal to 30 m (100 ft) and greater than 7.62 m (25 ft) is an approved acceptable means of compliance for an aircraft altimeter, provided that the following conditions are met:

(1) There is no conversion of the Gillham-encoded data to another format before it is input to the transponder unless failure detection can be provided, and the resolution (quantisation) is set in the transmitted data to indicate 30 m (100 ft).

Note 1: It is not recommended to install altimeters with a Gillham altitude encoder interface, as it supports a resolution of only 30 m (100 ft).

Note 2: Losses or errors of pressure altitude have an impact on the provision of separation by the air traffic control (ATC). It is, therefore, important to design the altitude pressure source to minimise the loss of this data or the provision of erroneous data.

Note 3: Further guidance on altitude measurement and coding systems can be found in EUROCAE Document ED-26.

(2) Altitude source comparison:

For aircraft equipped with ACAS II, where the available source of pressure altitude information is only in Gillham-encoded format, the requirement for detection of an altitude source or encoder failure can be satisfied by means of dual independent altitude corrected sensors, together with an altitude data comparator (which may be incorporated and enabled in the transponder). Similar provisions are also acceptable for alternative altitude information sources that do not signal erroneous data.

The flight deck interface should provide a means to inhibit the transmission of pressure altitude information for aircraft equipped with a Gillham-encoded altitude interface.

(d) If it is impractical to connect the transponder to the altitude source used to fly the aircraft, consistency may be achieved by:

(1) connecting the pressure altitude source directly (e.g. via a T-junction) to the same pitot/static-pressure line(s) as the altitude source being used to fly the aircraft; and

(2) ensuring that the pressure altitude source has built-in test equipment (BITE) that permanently or frequently runs an automatic system self-test and triggers a ‘FAIL’ annunciator/indicator (e.g. an amber light) in the pilot’s normal field of view upon detection of a failure; and

(3) ensuring that the altitude source meets design and performance standards that achieve an adequate level of integrity of its output, to mitigate the risk of a possible inconsistency

CS-ACNS Issue 5 Subpart D — Surveillance (SUR)

Section 2 – Mode S elementary surveillance

Annex to EDD 2024/003/R Page 141 of 270

between the output of the altitude source and the altimeters used by the flight crew to fly the aircraft.

The altitude source may be integrated into the transponder if the above-mentioned requirements are met.

(e) The provision of manual or automatic selection of the altitude source is an acceptable means of compliance.

[Issue: CS-ACNS/4]

CS ACNS.D.ELS.030 Flight deck interface (See AMC1 ACNS.D.ELS.030 )

(a) A means is provided :

(1) to select Mode A Code, including emergency indicators;

(2) to initiate the IDENT (SPI) feature;

(3) for an aircraft identification to be inserted by the flight crew if the aircraft uses variable aircraft identification;.

(4) to notify the flight crew when the transmission of pressure altitude information has been inhibited, if a means to inhibit the transmission of pressure altitude is provided;

(5) to select the transponder to the ‘standby’ or ‘OFF’ condition;

(6) to indicate the non-operational status or failure of the transponder system without undue delay and without the need for flight crew action;

(7) to display the selected Mode A code to the flight crew;

(8) to display the aircraft identification to the flight crew; and

(b) Input which is not intended to be operated in flight, is not readily accessible to the flight crew.

AMC1 ACNS.D.ELS.030 Flight deck interface Modes of operation should be identified. Attention should be closely paid to line select keys, touch screens or cursor controlled trackballs as these can be susceptible to unintended mode selection resulting from their location in the flight deck.

SYSTEM PERFORMANCE REQUIREMENTS

CS ACNS.D.ELS.040 Integrity The Mode S ELS airborne surveillance system integrity is designed commensurate with a ‘minor‘ failure condition.

CS ACNS.D.ELS.045 Continuity (See AMC1 ACNS.D.ELS.045)

The Mode S ELS airborne surveillance system is designed to provide a level of continuity that supports the intended operation with a remote probability of failure.

CS-ACNS Issue 5 Subpart D — Surveillance (SUR)

Section 2 – Mode S elementary surveillance

Annex to EDD 2024/003/R Page 142 of 270

[Issue: CS-ACNS/4]

AMC1 ACNS.D.ELS.045 Continuity The allowable quantitative probability of loss of the Mode S functionality per flight hour should be less than or equal to 2 × 10–4 (i.e. the mean time between failures, which is equal to or greater than 5 000 flight hours).

[Issue: CS-ACNS/4]

INSTALLATION REQUIREMENTS

CS ACNS.D.ELS.050 Dual/multiple transponder installation (See AMC1 ACNS.D.ELS.050)

If more than one transponder is installed, simultaneous operation of transponders is prevented.

AMC1 ACNS.D.ELS.050 Dual/multiple transponder installation When dual or multiple transponders are installed on an aircraft, a common control interface/panel should be provided to ensure that only one transponder is active at a given time, and to ensure that the Mode A code and Aircraft Identification changes are applied to the active transponder.

CS ACNS.D.ELS.055 ICAO 24-bit Aircraft address The ICAO 24-bit aircraft address assigned by the competent authority is correctly implemented on each transponder.

CS ACNS.D.ELS.060 Antenna installation (See AMC1 ACNS.D.ELS.060)

(a) The installed antenna(s) has (have) a resulting radiation pattern which is (are) vertically polarised, omnidirectional in the horizontal plane, and has (have) sufficient vertical beam width to ensure proper system operation during normal aircraft manoeuvres.

(b) Antenna(s) is/are located such that the effect on the far field radiation pattern(s) by the aircraft structure are minimised.

AMC1 ACNS.D.ELS.060 Antenna Installation (a) Antenna locations recommended by the aircraft manufacturer do not need to be revalidated.

(b) Antenna performance for new locations should be validated in flight by ground measurements or simulation modelling.

(c) The distance between ATC Transponder antenna should be at least 40 cm and the distance between ATC Transponder antenna and other antenna (e.g. ACAS, DME) should satisfy the appropriate isolation and longitudinal separation limits.

(d) When the Mode S ELS surveillance installation is using two antennas, the horizontal distance between the two antennas should be less than 7.6m

CS-ACNS Issue 5 Subpart D — Surveillance (SUR)

Section 2 – Mode S elementary surveillance

Annex to EDD 2024/003/R Page 143 of 270

CS ACNS.D.ELS.065 Antenna diversity (See AMC1 ACNS.D.ELS.065)

Aircraft with a maximum certified take-off mass in excess of 5700 kg or a maximum cruising true airspeed capability, under International Standard Atmosphere (ISA) conditions, in excess of 130 m/s (250 knots) operates with an antenna diversity installation.

AMC1 ACNS.D.ELS.065 Antenna Diversity (a) The aircraft maximum cruising true airspeed may be determined using one of the 3 following

options:

(1) Where the Aircraft Flight Manual or Pilot’s Operating Handbook gives more than one table of true airspeed values for a range of temperatures, the table which gives the maximum true airspeed, should be used;

(2) For some aircraft, the maximum cruising true airspeed is not obtained at the maximum operating altitude. In those cases, the maximum true airspeed has to be considered and not the true airspeed at maximum operating altitude;

(3) Aircraft which do not state the maximum cruising true airspeed under ISA conditions in their Aircraft Flight Manual or Pilot’s Operating Handbook, may use the following alternative method to calculate maximum cruising true airspeed:

(i) Use the maximum operating values of altitude and airspeed (i.e. VNO, or VMO/MMO as applicable) quoted in the Limitations section of the Aircraft Flight Manual or Pilot’s Operating Handbook to calculate the maximum cruising true airspeed of the aircraft. If the aircraft is unpressurised, an altitude of 8 000 feet may be used as the maximum ‘normal’ operating altitude.

(ii) For example, using a maximum ‘normal’ operating altitude of 2 400 m (8 000 feet) for an unpressurised aircraft, and a maximum operating airspeed of 110 m/s (215 knots), (as stated in the Aircraft Flight Manual or Pilot’s Operating Handbook, e.g. VNO = 110 m/s (215 knots)) then the aircraft has an equivalent TAS capability of 128 m/s (250 knots) in the ICAO Standard atmosphere. The calculation may be made using a pilot’s TAS computer.

(b) For airships, the applicant should demonstrate the need or otherwise for antenna diversity. The demonstration should be based on the construction techniques and size of the airship.

(c) The transponder DDP should indicate the letter ‘d’ in the transponder capability declaration to indicate antenna diversity capability.

CS-ACNS Issue 5 Subpart D — Surveillance (SUR)

Section 3 – Mode S Enhanced Surveillance

Annex to EDD 2024/003/R Page 144 of 270

SECTION 3 – MODE S ENHANCED SURVEILLANCE

GENERAL

CS ACNS.D.EHS.001 Applicability (See AMC1 ACNS.D.EHS.001)

(a) This section provides standards for airborne Mode S EHS installations which provide on request (through Mode S replies elicited by Mode S interrogations) airborne parameters in addition to parameters provided by ELS installations compliant with Section 2.

Note: The criteria that are applicable to airborne installations providing spontaneously (through ADS-B Extended Squitters) airborne parameters are specified in Section 4.

(b) This certification specification is applied together with Mode S Elementary Surveillance certification specification defined in Section 2.

AMC1 ACNS.D.EHS.001 Applicability Background information on Mode S EHS systems is provided in Appendix C – Background information on Mode S EHS.

Provided that the differences listed in Appendix E – Differences between CS ACNS.D.EHS and EASA AMC 20-13 have also been addressed, then previous declarations of compliance with EASA AMC 20-13 (Certification of Mode S Transponder Systems for Enhanced Surveillance), supplemented with the additional assessments, are also acceptable means of compliance.

Note: In accordance with Regulation (EU) No 1207/2011, fixed-wing aircraft having a maximum take-off mass greater than 5 700 kg or a maximum cruising true airspeed greater than 128.6 m/s (250 knots) and operating flights as general air traffic in accordance with instrument flight rules in the airspace within the ICAO EUR and AFI regions where EU Member States are responsible for the provision of air traffic services (ATS) are to be compliant with CS-ACNS, Subpart D, Section 3.

[Issue: CS-ACNS/4]

SYSTEM FUNCTIONAL REQUIREMENTS

CS ACNS.D.EHS.010 Transponder characteristics (See AMC1 ACNS.D.EHS.010)

The transponder is an approved Mode S transponder with EHS capability.

AMC1 ACNS.D.EHS.010 Transponder characteristics (a) The means of compliance defined in AMC1 ACNS.D.ELS.010 should be followed, with the

exception that the transponder DDP should indicate a label ‘n’ in the transponder capability declaration to reflect ELS and EHS capabilities.

Note: Such transponders meet the requirements specified in EUROCAE ED-73E section 3.30 for EHS capabilities. If the transponder is compliant with EUROCAE ED-73E, it provides register format corresponding to a Mode S sub-network version 5.

CS-ACNS Issue 5 Subpart D — Surveillance (SUR)

Section 3 – Mode S Enhanced Surveillance

Annex to EDD 2024/003/R Page 145 of 270

(b) The Mode S sub-network format should be 3 or above.

Note : The use of the highest Mode S sub-network version format is recommended.

CS ACNS.D.EHS.015 Data transmission (See AMC1 ACNS.D.EHS.015)

(a) The surveillance system provides in the Mode S reply the following downlink aircraft parameters, where available on a digital bus, in addition to those specified in CS ACNS.D.ELS.015:

(1) MCP/FCU Selected Altitude;

(2) Roll Angle;

(3) True Track Angle;

(4) Ground Speed;

(5) Magnetic Heading;

(6) Indicated Airspeed or Mach No;

(7) Vertical rate: Barometric Altitude rate or Inertial vertical Velocity. When barometric altitude rate field is provided, it is derived solely from barometric measurement;

(8) Barometric Pressure Setting in use minus 80 000 Pascal; and

(9) Track Angle Rate or True Airspeed.

(b) The sensor sources connected to the active transponder are the sensors relevant to the aircraft flight profile.

(c) All transmitted parameters are correct and are correctly indicated as available.

[Issue: CS-ACNS/4]

AMC1 ACNS.D.EHS.015 Data transmission (a) The EHS capability compliance verification should address all the Mode S transponder registers

that are indicated as available in the Mode S Specific Services Capability reports (registers). The compliance verification should include a list of transponder registers supported by the installation, including the parameters that are available in each register. The list should contain the registers that are indicated as available in the Mode Specific Capability reports (1816 to 1C16), except the following registers:

(1) registers managed by the transponder to support the Mode S airborne initiated protocol (0216, 0316, 0416);

(2) registers containing extended squitters information (0516, 0616, 0716, 0816, 0916, 0A16);

(3) aircraft capability reporting (1016 to 1F16);

(4) Aircraft Identification (2016);

(5) ACAS RA report (3016); and

(6) transponder dependant information (5F16, E316, E416, E716, EA16).

Note 1: An example of a minimum list of registers to support EHS is provided in Subpart D Appendix C.

CS-ACNS Issue 5 Subpart D — Surveillance (SUR)

Section 3 – Mode S Enhanced Surveillance

Annex to EDD 2024/003/R Page 146 of 270

Note 2: An example of other registers and parameters is provided in Subpart D Appendix C.

(b) Verification of operation

(1) All the transponder registers containing data as defined in (a) should be verified to ensure correct data is transmitted by the Mode S transponder.

Note: Format and resolution of airborne parameters can be found in ED-73E Volume 2 or in ICAO Doc 9871 Edition 2.

(2) Where a register is declared available but a parameter within that register is not available, it is necessary to verify that the status of the parameter is declared invalid in the corresponding aircraft register.

Note 1: Some parameters are particularly difficult to measure statically. To ensure that these parameters (e.g. Roll Angle, Track Angle Rate, Inertial Vertical Velocity) are correctly received from the sensor and transmitted by the transponder, it is acceptable to test that the correct transponder register is transmitted (by the transponder), that the value of the parameter status bit is valid (status bit = 1), and the value of the parameter field is set to zero when aircraft is not moving on the ground. Alternatively, for such parameters which remain invalid in static condition, ground test may use simulation if simulated data bus signal meets sensor data bus specifications, the same data bus provides at least one other valid parameter which is tested and sensor specifications clearly establish availability conditions and format of the simulated data parameter.

Note 2: Due to the limitations of the static tests, a recommended option is to perform a flight and record the content of the different transponder registers (as extracted by a Mode S ground station) to verify that all parameters listed in (a) are changing in accordance with pilot input and aircraft attitude and manoeuvre.

Note 3: To minimise the certification effort for transponder follow-on installations, the applicant may claim from the responsible authority credit for applicable certification and test data obtained from equivalent aircraft installations. This is acceptable for a parameter only if all related equipment connected to the transponders are of the same type and same software revision number.

(c) Aircraft parameters

(1) Selected Altitude

(i) MCP/FCU Selected Altitude

Selected level input to the MCP or FCU should be used.

In case there is no MCP/FCU Selected Altitude function, it is accepted to use the information provided by an altitude alerter.

(ii) FMS Selected Altitude

When available, it is recommended that the FMS Selected altitude field is provided.

Note: This will allow the reporting of the intermediate selected altitudes during applications (e.g. Continuous Descent Operations) when the FMS provides the guidance input to the auto-pilot.

(iii) MCP/FCU mode bits

When data is available, it is recommended (optional) to provide information on autopilot mode which is selected by the flight crew.

CS-ACNS Issue 5 Subpart D — Surveillance (SUR)

Section 3 – Mode S Enhanced Surveillance

Annex to EDD 2024/003/R Page 147 of 270

Note: It is accepted to set this bit to zero rather than providing wrong information.

(iv) Target Altitude source bits

The target altitude source bits are used to indicate the source (e.g. FCU/MCP, FMS) which provides the next level at which the aircraft will level off. This is also referred to as the Target Altitude. However, the necessary data may be inconsistent or not accessible. In this case, the status of target altitude source bits should indicate no source information provided (set to zero).

Note: It is also acceptable that status of target altitude source bits is set to valid and target altitude source is set to 00 to indicate unknown.

(2) Vertical Rate

The Barometric Altitude Rate should contain value solely derived from barometric measurement.

When different sources are available, the Inertial Vertical Velocity should contain data coming from the most accurate and steady source.

Note 1: The vertical rate can be provided in the Barometric Altitude Rate and/or the Inertial Vertical Velocity fields of register 6016. Both the Barometric Altitude Rate and the Inertial Vertical Velocity can be transmitted simultaneously.

Note 2: The Barometric Altitude Rate is usually very unsteady.

Note 3: The Inertial Vertical Velocity (derived from IRS, AHRS and/or GPS) information is more filtered and smoothed.

(3) Barometric Pressure Setting

If operating with reference to the standard pressure setting, the Barometric Pressure Setting field should indicate standard pressure value equivalent to 1.01325 105 Pa.

(4) Track Angle Rate or True Airspeed

If Track Angle Rate data cannot be readily provided due to the aircraft configuration, True Airspeed data should be substituted.

(5) Roll Angle

It is difficult to test different values of Roll Angle when the aircraft is on the ground. To ensure that this parameter is correctly received from the sensor and transmitted by the transponder, it is acceptable to test that the Roll Angle field in register 5016 contains a credible value, consistent with aircraft roll angle on the ground, and the Roll Angle Status bit indicates valid data.

(6) True Track Angle

It is difficult to test different values of True Track Angle when the aircraft is on the ground. To ensure that this parameter is correctly received from the sensor and transmitted by the transponder, it is acceptable to test that the True Track Angle field in register 5016 contains a value and the True Track Angle Status bit indicates valid data.

(7) Ground Speed

It is difficult to test different values of Ground Speed when the aircraft is on the ground. To ensure that this parameter is correctly received from the sensor and transmitted by the transponder, it is acceptable to test that the Ground Speed field in register 5016

CS-ACNS Issue 5 Subpart D — Surveillance (SUR)

Section 3 – Mode S Enhanced Surveillance

Annex to EDD 2024/003/R Page 148 of 270

contains a value, consistent with the speed of the aircraft on the ground (close to zero if the aircraft is not moving) and the Ground Speed Status bit indicates valid data.

(8) Magnetic Heading

To ensure that this parameter is correctly received from the sensor and transmitted by the transponder, it is acceptable to test that the Magnetic Heading field in register 6016 contains a value, consistent with the magnetic heading of the aircraft, and the Magnetic Heading Status bit indicates valid data.

(9) Indicated Airspeed or Mach No

Indicated Airspeed and Mach No are considered as a single parameter. Both should be provided where available.

To ensure that these parameters are correctly received from the sensor and transmitted by the transponder, it is acceptable to test that the Indicated Airspeed or Mach fields in register 6016 contain a value, consistent with the indicated airspeed or Mach No generated via a test set, and the Indicated Airspeed or Mach Status bits indicate valid data.

(d) Sensor Sources

Particular attention should be given to the interface between data sources and transponders when multiple transponders and multiple sensors are employed. In this context, ‘sensors’ refers to FMS, IRS, AHRS, ADS, GPS, or Data Concentrator (or other) systems used to provide data to the transponder.

The crew should be aware, at all times, which sensors are providing information to the active transponder.

In an installation, where automatic sensor selection for the active transponder is not provided, the captain’s side transponder should utilise the captain’s side sensors, and the co-pilot’s side transponder should utilise the co-pilot’s side sensors.

Data parameters from different sensors of the same type should not be mixed.

Note: For example, Mode-C or Mode-S altitude reporting information from ADC source #1 should not be mixed with reporting of TAS, Baro Vertical Rate, Mach from ADC source #2. In this case, partially blocking of data output from either ADC source #1 or #2 will cause uncorrelated results. This could result in problems with ATC ground processing of the data.

Where only single sensors are available (i.e. single FMS), it is permissible to connect the single sensor to multiple transponders. It should be noted that this may result in reduced operational availability should the single sensor fail.

SYSTEM PERFORMANCE REQUIREMENTS

CS ACNS.D.EHS.020 Integrity The Mode S EHS airborne surveillance system integrity is designed commensurate with a ‘minor’ failure condition for the downlink aircraft parameters listed in CS ACNS.D.EHS.015.

CS-ACNS Issue 5 Subpart D — Surveillance (SUR)

Section 3 – Mode S Enhanced Surveillance

Annex to EDD 2024/003/R Page 149 of 270

CS ACNS.D.EHS.025 Continuity The Mode S EHS airborne surveillance system continuity is designed to an allowable qualitative probability of ‘probable’ for the downlink aircraft parameters listed in CS ACNS.D.EHS.015.

CS-ACNS Issue 5 Subpart D — Surveillance (SUR)

Section 4 – 1090 MHz Extended Squitter ADS-B

Annex to EDD 2024/003/R Page 150 of 270

SECTION 4 – 1090 MHZ EXTENDED SQUITTER ADS-B

GENERAL

CS ACNS.D.ADSB.001 Applicability (See GM1 ACNS.D.ADSB.001)

This section provides standards for 1090 MHz Extended Squitter (ES) ADS-B Out installations.

GM1 ACNS.D.ADSB.001 Applicability With respect to 1 090 MHz ES ADS-B Out installations, the material in this section is to a large degree in line with the corresponding FAA AC 20-165A material. Differences between the two documents are listed in Appendix J. This guidance may be of use when showing of compliance with both documents is required.

The requirements of CS ACNS.D.ADSB fully cover (and exceed) the requirements of AMC 20-24 (Certification Considerations for the Enhanced ATS in Non-Radar Areas using ADS-B Surveillance (ADS-B-NRA) Application via 1090 MHz Extended Squitter). Therefore, aircraft that comply with CS ACNS.D.ADSB also comply with AMC 20-24 but not vice versa.

The approval of on-board systems receiving and processing ADS-B messages in support of air-to-air applications is outside the scope of Subpart D, Section 4.

Note: In accordance with Regulation (EU) No 1207/2011, aircraft having a maximum take-off mass greater than 5 700 kg or a maximum cruising true airspeed greater than 128.6 m/s (250 knots) and operating flights as general air traffic in accordance with instrument flight rules in the airspace within the ICAO EUR and AFI regions where EU Member States are responsible for the provision of air traffic services (ATS) are to be compliant with CS-ACNS, Subpart D, Section 4.

[Issue: CS-ACNS/4]

SYSTEM FUNCTIONAL REQUIREMENTS

CS ACNS.D.ADSB.010 ADS-B Out system approval (See GM1 ACNS.D.ADSB.001)

The equipment contributing to the ADS-B Out function is approved.

AMC1 ACNS.D.ADSB.010 ADS-B Out system approval Equipment Qualification

For equipment qualification, refer to AMC1 ACNS.D.ADSB.030 through to AMC1 ACNS.D.ADSB.090.

The ADS-B Out functionality should be demonstrated by ground testing, using ramp test equipment where appropriate, that verifies during nominal system operation, the correctness of the aircraft derived surveillance data contained in the ADS-B messages, and the functioning of system monitoring tools/fault detectors including any ADS-B self-test features.

CS-ACNS Issue 5 Subpart D — Surveillance (SUR)

Section 4 – 1090 MHz Extended Squitter ADS-B

Annex to EDD 2024/003/R Page 151 of 270

ADS-B OUT DATA

CS ACNS.D.ADSB.020 ADS-B Out Data Parameters (See AMC1 ACNS.D.ADSB.020(a-b))

(a) The ADS-B Out system provides the following minimum set of data parameters:

(1) Aircraft Identification;

(2) Mode A Code;

(3) ICAO 24-bit aircraft address;

(4a) Airborne Horizontal Position — Latitude and Longitude;

(4b) Airborne Navigation Integrity Category: NIC;

(4c) Airborne/Surface Navigation Accuracy Category for Position: NACp;

(4d) Airborne/Surface Source Integrity Level: SIL;

(4e) Airborne/Surface System Design Assurance: SDA;

(5) Pressure Altitude (incl. NICbaro);

(6) Special Position Identification (SPI);

(7a) Emergency Status;

(7b) Emergency Indication;

(8) 1090 ES Version Number;

(9a) Airborne velocity over Ground — (East/West and North/South);

(9b) Airborne/Surface Navigation Accuracy Category for Velocity: NACv;

(10) Emitter Category;

(11) Vertical Rate;

(12a) Surface Horizontal Position — Latitude and Longitude;

(12b) Surface Navigation Integrity Category: NIC;

(13) Surface Ground Track;

(14) Movement (surface ground speed);

(15) Length/width of Aircraft;

(16) GPS Antenna Longitudinal Offset;

(17a) Geometric Altitude; and

(17b) Geometric Altitude Quality: GVA.

(b) Where available in a suitable format, the ADS-B Out system provides the following data parameters:

(1) Selected Altitude;

(2) Barometric Pressure Setting; and

(3) ACAS Resolution Advisory.

CS-ACNS Issue 5 Subpart D — Surveillance (SUR)

Section 4 – 1090 MHz Extended Squitter ADS-B

Annex to EDD 2024/003/R Page 152 of 270

AMC1 ACNS.D.ADSB.020(a-b) ADS-B Out data parameters During ADS-B Out system installation testing, all the parameters that are broadcast should be demonstrated to be correct for each installed ADS-B transmit unit, i.e. the transmitted data should be in line with the respective source data.

The Emitter Category, Aircraft Length and Width and GPS Antenna Offset parameters might be either configured as a fixed value during ADS-B Out system installation, or provided via a variable data interface. In both cases, during installation, the respective settings should be verified to be correctly set.

The ADS-B Horizontal Position System Design Assurance (SDA) parameter indicates the probability of an ADS-B Out system malfunction causing false or misleading position information or position quality metrics to be transmitted. SDA may be pre-set at installation for systems that do not utilise multiple position sources with different design assurance levels, otherwise the system should be capable of adjusting the SDA broadcast parameter to match the position source being employed at the time of transmission. ADS-B transmit equipment that is compliant with AMC1 ACNS.D.ADSB.030 and that is directly connected to a position source compliant with AMC1 ACNS.D.ADSB.070 may set the SDA to ‘two’ without further analysis. For more complex ADS-B installations, a system safety assessment is required to set the SDA. Basically, the lowest design assurance level of one system in the horizontal position data transmission chain should define the SDA value.

Additional guidance material on the required surveillance data parameters are provided in Appendix H Part 1 and Part 2.

Appendix H Part 6 provides matrices of the so-called BDS register fields as used by the 1090 ES ADS-B transmit unit to broadcast the ADS-B Out parameters. These matrices detail the ADS-B Out data requirements at data field level for general understanding and in support of integration testing, as appropriate.

If installations transmit ADS-B Out data that do not meet some requirements of the Subpart D Section 4, the respective data should only be transmitted with a ‘zero’ quality indication (if a quality indication is defined in the ADS-B Out transmit system).

CS ACNS.D.ADSB.025 Provision of data (See AMC1 ACNS.D.ADSB.025(a) and (c))

(a) All data provided by the ADS-B Out system comes from approved sources.

(b) The data transmitted by the ADS-B Out system originates from the same data source as used in the transponder replies to Mode S interrogations.

(c) When a data quality indication is required, it is provided to the ADS-B transmit unit together with the associated data parameter and it expresses the actual quality of the respective data as valid at the time of applicability of the measurement.

[Issue: CS-ACNS/4]

AMC1 ACNS.D.ADSB.025(a) Provision of data — Approved sources (a) See AMC1 ACNS.D.ADSB.070-090 for details on the approval of the respective data sources.

(b) For transmission of optional data items, the following provisions should be considered:

CS-ACNS Issue 5 Subpart D — Surveillance (SUR)

Section 4 – 1090 MHz Extended Squitter ADS-B

Annex to EDD 2024/003/R Page 153 of 270

(1) Airspeed

In case of a loss of GNSS horizontal velocity data, the ADS-B transmit unit normally switches to broadcast airspeed information (using subtypes 3 and 4 of register 0916).

Therefore, if airspeed data is provided to the ADS-B transmit unit, it should be provided by an approved airspeed source that is providing data intended for use by the flight crew. An air data computer meeting the minimum performance requirements of holding an EASA equipment authorisation in accordance with ETSO-C106 (JTSO-C106) is an acceptable source.

(2) Heading

In case of a loss GNSS ground track and if heading is provided to the ADS-B transmit unit, the heading source should hold an EASA equipment authorisation in accordance with ETSO-C5e (JTSO-C5e) or any revision of ETSO-C6d (JTSO-C6d).

(3) Other Data Parameters

The Intent Change Flag should be set as appropriate to indicate the availability of information in the Mode S registers 4016 to 4216.

If available, Selected Heading information should come from approved data sources.

The 1090 ES IN capability field should be set correctly.

AMC1 ACNS.D.ADSB.025(c) Provision of data – Data quality indication and associated data Data quality indications for the horizontal position containment bound (NIC) and horizontal position accuracy bound (NACp) should be provided to the ADS-B transmit unit together with the corresponding horizontal position information within the same data set.

Data quality indications for the horizontal position source integrity level (SIL) and system design assurance level (SDA) may be preset at installation. Systems that utilise multiple GNSS-based position sources with different design assurance levels or source integrity levels, should be capable of adjusting the SDA and SIL quality indications to match the position source that is employed at the time of transmission.

The horizontal velocity accuracy bound (NACv) and vertical geometric altitude accuracy bound (GVA) should be dynamically provided to the ADS-B transmit unit together with the corresponding velocity and geometric altitude information within the same data set. However, NACv and GVA may be also preset at installation.

For further guidance on the ADS-B data quality indicators, refer to AMC1 ACNS.D.ADSB.070(a).

ADS-B TRANSMIT UNIT

CS ACNS.D.ADSB.030 ADS-B Transmit Unit Approval (See AMC1 ACNS.D.ADSB.030)

The ADS-B transmit unit is approved and it is integrated in the Mode S transponder.

CS-ACNS Issue 5 Subpart D — Surveillance (SUR)

Section 4 – 1090 MHz Extended Squitter ADS-B

Annex to EDD 2024/003/R Page 154 of 270

AMC1 ACNS.D.ADSB.030 ADS-B Transmit unit installation To be approved, the ADS-B transmit unit should hold an EASA equipment authorisation in accordance with ETSO-C166b and ETSO-C112d, including any additional requirements as required to comply with the provision of the AMC’s to Subpart D section 4 (e.g. On-the-ground status determination and maximum NIC encoding). Where such additional requirements apply, it is expected that the ADS-B transmit unit manufacturer supplies compliance information through a Declaration of Design and Performance (DDP), or an equivalent document

The broadcast of Selected Altitude and Barometric Pressure Setting are optional for equipment meeting ETSO-C166b and equipment should implement this optional functionality if available and in a suitable format

If using earlier versions of ETSO-C112( ), it should to be demonstrated that all applicable requirements from EUROCAE ED-102A have been implemented. This can be achieved by a positive deviation of compliance to previous versions of EUROCAE ED-73 that have been documented in the Declaration of Design and Performance (DDP).

CS ACNS.D.ADSB.035 ICAO 24-bit Aircraft address The ICAO 24 bit aircraft address is implemented as specified in CS ACNS.D.ELS.055.

CS ACNS.D.ADSB.040 Antenna diversity (See AMC1 ACNS.D.ADSB.040)

The ADS-B transmit unit employs antenna diversity under the same conditions as specified in CS ACNS.D.ELS.065.

AMC1 ACNS.D.ADSB.040 Antenna Diversity The 1090 ES data protocol includes a bit to indicate, at any time, if only one or both antennas (if installed) are functional. The corresponding parameter for the Single Antenna bit is contained in register 6516 (message element bit ‘30’) and should be set to the appropriate value.

Note 1: For detailed guidance on the required antenna diversity as a function of aircraft maximum cruising true airspeed capability, refer to AMC1 ACNS.D.ELS.065.

Note 2: For further guidance on antenna installations, see CS ACNS.D.ELS.060, CS ACNS.D.ELS.065, AMC1 ACNS.D.ELS.060 and AMC1 ACNS.D.ELS.065.

CS ACNS.D.ADSB.045 Antenna installation The antenna is installed as specified in CS ACNS.D.ELS.060.

CS ACNS.D.ADSB.050 Transmit power The ADS-B transmit unit has a peak transmit power as specified in CS ACNS.D.ELS.010(c);(d).

CS-ACNS Issue 5 Subpart D — Surveillance (SUR)

Section 4 – 1090 MHz Extended Squitter ADS-B

Annex to EDD 2024/003/R Page 155 of 270

CS ACNS.D.ADSB.055 Simultaneous operation of ADS-B transmit units (See AMC1 ACNS.D.ADSB.)

If more than one ADS-B transmit unit is installed, simultaneous operation of the transmit systems is prevented.

AMC1 ACNS.D.ADSB.055 Simultaneous operation of ADS-B transmit units Manual switching between transmitters is considered acceptable.

Note: The requirement applies to ADS-B transmit units broadcasting on the same data link. It does not preclude simultaneous operation of dual link installations.

CS ACNS.D.ADSB.060 On-the-ground status determination (See AMC1 ACNS.D.ADSB.060)

(a) The on-the-ground status is determined and validated by the ADS-B Out system.

(b) The on-the-ground status is not set by a manual action.

AMC1 ACNS.D.ADSB.060 On-the-ground status Determination For aircraft with retractable landing gear, the on-the-ground status determination is typically provided through a landing gear weight-on-wheels switch. For aircraft that have fixed-gear, the ADS-B Out system should be able to determine the air-ground status of the aircraft using other means.

Installations that provide a means to automatically determine on-the-ground status based on input from other aircraft sensors are acceptable if they are demonstrated to accurately detect the status. Otherwise, ground status validation algorithms should be implemented, using speed thresholds that match the typical aircraft’s rotation speed as closely as possible.

It is noted that for the validation of a directly determined on-the-ground status that is not validated outside the ADS-B transmit function, validation against the aircraft’s typical rotation speed (rather than a fixed value of 50 m/s (100 knots)) might not have been tested in accordance with ETSO-C166b. If that is the case, it is expected that the ADS-B transmit unit manufacturer supplies compliance information through a Declaration of Design and Performance (DDP), or an equivalent document.

Detailed guidance material is provided in Appendix I.

HORIZONTAL POSITION AND VELOCITY DATA SOURCES

CS ACNS.D.ADSB.070 Horizontal Position and Velocity Data Sources (See AMC1 ACNS.D.ADSB.070)

(a) The horizontal position is derived from GNSS data.

(b) The GNSS receiver based horizontal position and velocity data source is approved and performs, as a minimum, horizontal position receiver autonomous integrity monitoring (RAIM) and fault detection and exclusion (FDE).

CS-ACNS Issue 5 Subpart D — Surveillance (SUR)

Section 4 – 1090 MHz Extended Squitter ADS-B

Annex to EDD 2024/003/R Page 156 of 270

(c) Horizontal velocity data stems from the same source as horizontal position data.

AMC1 ACNS.D.ADSB.070 Horizontal Position and Velocity Data Sources (a) GNSS Standards

(1) Basic GNSS System Approval

To be approved, the horizontal position and velocity data source should hold an EASA equipment authorisation in accordance with either ETSO-C129a, or ETSO-C196, or ETSO- C145/ETSO-C146, including the additional qualification requirements as specified in paragraph (2) below.

(2) Additional GNSS Receiver Qualification Requirements

In order to fully address the standard associated with ADS-B Out, an ETSO authorisation alone may not be sufficient to ensure ADS-B compatibility. The position and velocity source should also comply with the following requirements (i) to (vi).

It is expected that compliance with these requirements is demonstrated by the equipment manufacturer and documented in the Declaration of Design and Performance (DDP), or an equivalent document. Detailed guidance material on the qualification requirements is provided in Appendix H Part 5.

(i) GNSS system must provide a latitude and longitude output.

Note: ETSO-C129a does not cater for full compliance with this requirement.

(ii) The horizontal position integrity containment should have been qualified as per Appendix H Part 5 paragraph 1;

Note: Horizontal Uncertainty Level (HUL) information does not fulfil CS ACNS.D.ADSB.070.

(iii) The maximum time to alert for the indication of a signal-in-space data integrity failure should be 10 seconds as per Appendix H in Part 5 paragraph 1;

(iv) Navigation modes that would force the NIC value temporarily to ‘zero’ whilst the actual horizontal position integrity containment bound would meet the NIC requirements in Appendix H Part 3 Table 20, should not be installed.

(v) The horizontal position source accuracy output should have been qualified as per Appendix H Part 5 paragraph 2;

(vi) The horizontal position source latency and timing characteristics should have been documented (see Appendix H Part 5 paragraph 3);

(vii) The horizontal velocity accuracy output should have been qualified. If a dynamic horizontal velocity accuracy output is not provided, the transmitted horizontal velocity accuracy should be based on a worst case accuracy. If a dynamic horizontal velocity accuracy output is provided, the source should have been qualified for this quality indication accordingly as per Appendix H Part 5 paragraph 4.

In addition, a means should be provided to establish the condition when the horizontal velocity track angle accuracy exceeds plus/minus ‘eight’ degrees as per Appendix H Part 5 paragraph 4.

CS-ACNS Issue 5 Subpart D — Surveillance (SUR)

Section 4 – 1090 MHz Extended Squitter ADS-B

Annex to EDD 2024/003/R Page 157 of 270

(3) Interface Interoperability Aspects

It should be verified that the position and velocity information (including their respective quality indicators) received from the source are correctly interpreted by the ADS-B equipment.

(i) Horizontal Position Integrity Containment Bound

Some approved horizontal position sources may incorrectly output horizontal position integrity containment bounds of less than 75 meters. In such cases, it is accepted that the transmit unit limits the NIC value to ’eight’.

It is expected that the ADS-B transmit unit manufacturer supplies compliance information through a Declaration of Design and Performance (DDP), or an equivalent document.

(ii) Horizontal Velocity Format

The position and velocity source manufacturer should provide information describing how the horizontal velocity information is output (i.e. in a ground speed/track angle format versus north/east velocity format) and the protocols used.

(4) Data Quality Indicator Testing

By design and under nominal GNSS satellite constellation conditions, an ADS-B Out system that is compliant with CS ACNS.D.ADSB.070 should meet the required values of the horizontal position NIC, NACp, SIL and horizontal velocity NACv quality indicators (refer to Appendix H Part 3 Table 20).

(b) Installation Guidance

The GNSS based position sources should be installed in accordance with FAA AC 20-138B (or later).

Note: EASA is developing GNSS installation guidance, once published, should be used instead of the FAA material.

(c) Multiple Position and Velocity Data Sources

(1) Multiple Source Approval

Any position and velocity source that is interfaced to the ADS-B transmit unit, should meet the requirements of CS ACNS.D.ADSB.070.

(2) Source Priority

If multiple horizontal position data sources are interfaced with the ADS-B transmit unit, priority should be given to the source that provides the best ADS-B performance with respect to the horizontal position integrity containment bound (NIC)..

A change of the selection between sources should only take place when the not selected source has exceeded the NIC performance of the selected source for several seconds.

(d) Interconnecting Avionics

Interconnecting avionics between a horizontal position and velocity data source and the ADS-B transmit unit are not recommended.

If installed, interconnecting avionics should:

CS-ACNS Issue 5 Subpart D — Surveillance (SUR)

Section 4 – 1090 MHz Extended Squitter ADS-B

Annex to EDD 2024/003/R Page 158 of 270

(1) not output horizontal position and velocity data that has been blended with data from other sources;

(2) use GNSS horizontal velocity data to extrapolate the horizontal position data if extrapolation is deployed; and

(3) maintain full source resolution of the horizontal position and velocity data.

Interconnecting avionics that do not comply with the above may dilute the horizontal position accuracy achieved with GNSS-based sources, with detrimental effects on the usability of the ADS-B Out system.

Note: closely coupled GPS/IRS systems are not considered as interconnecting avionics.

OTHER DATA SOURCES

CS ACNS.D.ADSB.080 Data Sources as defined by Mode S Elementary and Enhanced Surveillance (See AMC1 ACNS.D.ADSB.080)

The data source requirements as defined for in section 2 and 3 of this subpart, are applicable.

AMC1 ACNS.D.ADSB.080 Data sources as defined by Mode S elementary and enhanced surveillance (a) General requirements

For the requirements and general guidance on the data sources providing the Mode S elementary and enhanced surveillance parameters, the following references to CS ACNS.D.ELS and CS ACNS.D.EHS apply:

(1) Aircraft Identification: CS ACNS.D.ELS.030(a)(3);

(2) Mode A Code: CS ACNS.D.ELS.030(a)(1);

(3) SPI: CS ACNS.D.ELS.030(a)(2);

(4) Emergency Mode/Status: CS ACNS.D.ELS.030(a)(1);

(5) Pressure Altitude: CS ACNS.D.ELS.025;

(6) MCP/FCU Selected Altitude: AMC1 ACNS.D.EHS.015(c)(1);

(7) Barometric Pressure Setting:AMC1 ACNS.D.EHS.015(c)(3);

(8) ACAS Operational/Resolution Advisory: AMC1 ACNS.D.ELS.015; and

(9) ICAO 24 bit Address: CS ACNS.D.ELS.050.

(b) Emergency Status

When transmitting the Mode A emergency status codes, the additional specific bits should be set (see Appendix H, Part 1, Definition 10).

(c) Pressure Altitude — NICbaro

For aircraft with an approved, non-Gillham altitude source, the Barometric Altitude Integrity Code ‘NICbaro’ should be set to ‘one’.

CS-ACNS Issue 5 Subpart D — Surveillance (SUR)

Section 4 – 1090 MHz Extended Squitter ADS-B

Annex to EDD 2024/003/R Page 159 of 270

For aircraft where the pressure altitude that is based on a Gillham coded input that has not been cross-checked against another source of pressure altitude, the ‘NICbaro’ should be set to ‘zero’. Otherwise, the ‘NICbaro’ should be set to ‘one’.

For general guidance on the ADS-B ‘NICbaro’ indicator that is associated with Pressure Altitude information, refer to Appendix H, Part 1, Definition 9.

(d) Vertical Rate

The Vertical Rate information should come from the most accurate and steady source.

In order to ensure that minimum performance requirements are met for Vertical Rate information, the following source prioritisation should be applied:

— Hybrid Vertical Rate Source: the information may be taken from a hybrid system which filters barometric vertical rate with an inertial reference unit (IRU) vertical rate and GNSS vertical rate, provided the accuracy of the vertical rate output is at least as good as barometric vertical rate sources (e.g. ETSO-C106).

— Blended Vertical Rate Source: the information may be taken from a blended system which filters IRU vertical rate and barometric vertical rate, provided the accuracy of the vertical rate output t is at least as good as barometric vertical rate sources (e.g. ETSO-C106).

— Barometric Vertical Rate Source: the information may be taken from an air data computer (ADC) holding an EASA equipment authorisation in accordance with ETSO-C106 or a vertical velocity instrument holding an EASA equipment authorisation in accordance with applicable revisions of ETSO-C8().

— GNSS Vertical Rate Source: GNSS vertical velocity equipment which have not been qualified in accordance with CS ACNS.D.ADSB.070 should not be interfaced with the ADS-B transmit unit.

Vertical Rate from an inertial sensor that is not blended with barometric altitude should not be transmitted. Neither should ADS-B transmit units derive a barometric altitude rate by sampling barometric altitude measurements.

The source bit for vertical rate (1090 ES register 0916, message bit ‘36’) should be coded as barometric when utilising barometric rate from an air data computer, or when using a blended or hybrid vertical rate. The source bit for vertical rate should only be coded as geometric when using vertical rate from a GNSS source.

Note: due to differences in the respective transmit formats, the above source prioritisation differs in some parts with the guidance applicable to Mode S Enhanced Surveillance as provided in AMC1 ACNS.D.EHS.015.

For general guidance on Vertical Rate data sources, refer to Appendix H, Part 1, Definition 14.

(e) Selected altitude (and related modes)

With respect to the various status and mode fields contained in Register 6216 (Subtype 1), the respective provisions of AMC1 ACNS.D.EHS.015(c)(1) apply to the ‘Selected Altitude Type’, ‘Status of MCP/FCU Mode Bits’, ‘VNAV Mode Engaged’, ‘Altitude Hold Mode’, and ‘Approach Mode’ information.

The population of the additional Autopilot Engaged and LNAV Mode Engaged fields status bits are optional but should be populated where the data is available.

[Issue: CS-ACNS/4]

CS-ACNS Issue 5 Subpart D — Surveillance (SUR)

Section 4 – 1090 MHz Extended Squitter ADS-B

Annex to EDD 2024/003/R Page 160 of 270

CS ACNS.D.ADSB.085 Geometric Altitude (See AMC1 ACNS.D.ADSB.085)

(a) Geometric Altitude is provided by the horizontal position and velocity source (see CS ACNS.D.ADSB.070).

(b) Geometric Altitude is transmitted as height above WGS-84 ellipsoid.

AMC1 ACNS.D.ADSB.085 Geometric Altitude (a) Geometric Altitude data source

The position source should output a vertical position accuracy metric to support the encoding of the Geometric Altitude GVA quality indicator.

GNSS position sources should provide the geometric altitude accuracy through the vertical figure of merit (VFOM). If that is the case, the vertical position source accuracy output by a GNSS receiver should have been qualified as per Appendix H Part 5 paragraph 5.

If the position source does not output a qualified vertical accuracy metric, the GVA parameter should be set to ‘zero’.

For general guidance on the GVA encoding, refer to Definition 20 in Appendix H of Subpart D.

(b) Geometric Altitude Reference

A GNSS position source compliant with CS ACNS.D.ADSB.070 provides Geometric Altitude, in its native format, as geocentric height above the earth’s ellipsoid shape. Height Above Ellipsoid (HAE) is described by the WGS-84 format.

Another altitude reference is described by the earth’s geoid, a surface on which the gravitational potential is constant and which approximates the (local) mean levels of all the earth's seas. The difference between the mathematically idealised smooth ellipsoid and irregular geoid surfaces varies between +106m to -85m across the earth. The related Mean Sea Level (MSL) altitude is then established as the sum of the HAE altitude and those local differences (using look-up tables). MSL is sometimes also referred to as Height-Above-Geoid (HAG).

A position source that only provides HAG or MSL altitude (ARINC label 076) but not HAE (ARINC label 370) should not be interfaced to the ADS-B transmit unit unless the ADS-B transmit unit can properly convert HAG/MSL to HAE, using the same HAG/MSL model as the position source (typically NATO STANAG Appendix 6). This should be based on position source installation instructions that specify a deterministic method to perform conversion to HAE, and be demonstrated during ADS-B transmit unit design approval. It is expected that the respective compliance information is supplied by the position and velocity source, and ADS-B transmit unit manufacturers through a Declaration of Design and Performance (DDP) or an equivalent document.

Note: Horizontal position sources compliant with Class 3 equipment approved under ETSO- C145c/C146c are required to output HAE altitude. The requirement has been implemented from revision C of RTCA/DO-229 onwards.

(c) Geometric Altitude Accuracy Quality Indicator Testing

If a qualified vertical accuracy metric is available, under nominal GNSS satellite constellation and visibility conditions, the transmitted GVA value should be a minimum of ‘one’.

CS-ACNS Issue 5 Subpart D — Surveillance (SUR)

Section 4 – 1090 MHz Extended Squitter ADS-B

Annex to EDD 2024/003/R Page 161 of 270

FLIGHT DECK CONTROL AND INDICATION CAPABILITIES

CS ACNS.D.ADSB.090 Flight deck interface (See AMC1 ACNS.D.ADSB.090(a) and AMC1 ACNS.D.ADSB.090(b))

(a) The control and display of surveillance data items is as per CS ACNS.D.ELS.030.

(b) A means is provided to indicate the non-operational status or failure of the ADS-B Out system without undue delay.

AMC1 ACNS.D.ADSB.090(a) Flight deck interface (a) Installations

(1) Data transmission and display consistency

The data transmitted by the active ADS-B transmit unit should be consistent with the data displayed to the flight crew.

Consistency may be demonstrated by using a compliant GNSS sensor connected to the transponder and the navigation equipment (i.e. the transponder and navigation equipment receive the same data from the GNSS source).

Where this is not practical, compliance may be demonstrated by installing a stand-alone GNSS receiver connected (only) to the transponder, provided that the GNSS receiver is approved in accordance with ETSO-C145c or ETSO-C146c (or later amendments).

Note 1: Operational Classes 1, 2 or 3 of RTCA DO-229D satisfy the ‘consistency’ criteria.

Note 2: The horizontal position data displayed to the flight crew may be based on data from more position sources than the one used for ADS-B transmissions.

(2) Single point of flight crew entry

Installations that do not provide a single point of flight crew entry for the transponder and the ADS-B transmit unit should be evaluated to ensure that dual entry of the Mode A code, SPI, and emergency status does not lead to the transmission by the active ADS-B transmit unit of inconsistent data, particularly when communicating an aircraft emergency.

(b) ADS-B off switch

If control is provided to enable or disable the ADS-B transmit unit, then the status of the active ADS-B transmit unit should clearly be indicated to the flight crew from their normal seated position.

The respective controls should be located such that inadvertent disabling is prevented.

[Issue: CS-ACNS/4]

AMC1 ACNS.D.ADSB.090(b) Flight Deck Interface ADS-B device or function failures, should be indicated in amber or in accordance with the flight deck annunciation philosophy, without undue delay, i.e. a response time within the order of one second.

ADS-B device or function failures may be indicated independently of each other; however, detailed operating instructions should be developed to describe the means to interpret indications.

CS-ACNS Issue 5 Subpart D — Surveillance (SUR)

Section 4 – 1090 MHz Extended Squitter ADS-B

Annex to EDD 2024/003/R Page 162 of 270

The ADS-B device or function failure indication should not be confused with an ACAS or Mode S system failure annunciations.

In case of an ADS-B function failure, it is expected that the transponder should continue to support the ACAS, Mode A/C and Mode S functions.

The proper indications of the ADS-B Out system failures should be tested.

SYSTEM PERFORMANCE REQUIREMENTS

CS ACNS.D.ADSB.100 Integrity (a) The ADS-B Out system integrity is designed commensurate with a ‘major’ failure condition for

the transmission of the following parameters:

(1) ICAO 24-bit aircraft address;

(2) Airborne Horizontal Position — Latitude and Longitude;

(3) Airborne Navigation Integrity Category: NIC;

(4) Airborne/Surface Navigation Accuracy Category for Position: NACp;

(5) Airborne/Surface Source Integrity Level: SIL;

(6) Airborne/Surface System Design Assurance: SDA;

(7) 1090 ES Version Number;

(8) Airborne velocity over Ground — East/West and North/South;

(9) Airborne/Surface Navigation Accuracy Category for Velocity: NACv;

(10) Emitter Category;

(11) Surface Horizontal Position — Latitude and Longitude;

(12) Surface Navigation Integrity Category: NIC;

(13) Surface Ground Track;

(14) Movement (surface ground speed);

(15) Length/width of Aircraft;

(16) GPS Antenna Offset;

(17) Geometric Altitude;

(18) Geometric Altitude Quality: GVA;

(b) The ADS-B Out system integrity is designed commensurate with a ‘minor‘ failure condition for the transmission of other data parameters.

CS ACNS.D.ADSB.105 Continuity (See AMC1 ACNS.D.ADSB.105)

The ADS-B Out system is designed to provide a level of continuity that supports the intended operation with a remote probability of failure.

[Issue: CS-ACNS/4]

CS-ACNS Issue 5 Subpart D — Surveillance (SUR)

Section 4 – 1090 MHz Extended Squitter ADS-B

Annex to EDD 2024/003/R Page 163 of 270

AMC1 ACNS.D.ADSB.105 Continuity The allowable quantitative probability of loss of the ADS-B Out functionality per flight hour should be less than or equal to 2 × 10–4 (i.e. the mean time between failures, which is equal to or greater than 5 000 flight hours).

[Issue: CS-ACNS/4]

HORIZONTAL POSITION AND VELOCITY DATA REFRESH RATE AND LATENCY

CS ACNS.D.ADSB.110 Horizontal position and velocity data refresh rate (See AMC1 ACNS.D.ADSB.110)

A horizontal position and velocity source calculates position and velocity data with a rate of at least 1 Hertz.

[Issue: CS-ACNS/4]

AMC1 ACNS.D.ADSB.110 Horizontal Position and Velocity Data Refresh For systems with a 1 Hertz computation rate, the output of position and velocity data can vary between 0.8 seconds and 1.2 seconds.

Note Faster position update rates reduce the latency of the transmitted position and velocity information and are therefore encouraged.

CS ACNS.D.ADSB.115 Horizontal Position and Velocity Total Latency (See AMC1 ACNS.D.ADSB.115 and 120)

Measured from the time of applicability within the source, the total latency of the horizontal position and horizontal velocity data introduced by the ADS-B Out system does not exceed 1.5 second.

CS ACNS.D.ADSB.120 Horizontal Position Uncompensated Latency (See AMC1 ACNS.D.ADSB.115 and 120)

The uncompensated latency of the horizontal position data introduced by the ADS-B Out System does not exceed 0.6 second.

AMC1 ACNS.D.ADSB.115 and 120 Horizontal Position and Velocity Total and Uncompensated Latency (a) Time of Applicability

With respect to the latency requirements in CS ACNS.D.ADSB.115 and CS ACNS.D.ADSB.120, the initial time of applicability (ITOA) is the time of validity of the position or velocity solution. Hence, the latency between the time of signal in space measurement (TOM) and this time of validity is excluded from the total latency budget.

CS-ACNS Issue 5 Subpart D — Surveillance (SUR)

Section 4 – 1090 MHz Extended Squitter ADS-B

Annex to EDD 2024/003/R Page 164 of 270

The transmit time of applicability (TTOA) equals the initial time of applicability plus the amount of compensated latency (CL), as valid at the time at which the ADS-B transmit unit broadcasts the position (or velocity) information (TOT).

(b) Compliance Demonstration

Total latency (TL) is the difference between time of transmission (TOT) and initial time of applicability (ITOA). The analysis of total latency includes the maximum asynchronous delay caused by the time difference of position (or velocity) updates arriving at the ADS-B transmit unit and of transmitting the information. It is noted that for ADS-B transmit units compliant with AMC1 ACNS.D.ADSB.030, this asynchronous delay can be up to 1.1 second.

Uncompensated latency (UL, or more generically a latency compensation error) is the difference between total latency (TL) and amount of compensated latency (CL) thereof. Therefore, uncompensated latency determines the transmit time of applicability (TTOA). The GNSS time mark if provided to the transmit system, can be used by the ADS-B transmit unit to reduce uncompensated latency. It is possible for compensation algorithms to overcompensate for the effects of latency, also as a result of the desired attempt to account for latency external to the ADS-B transmit unit. This might lead to transmitting a position that is out in front of the actual aircraft position rather than behind the actual aircraft position. This is acceptable as long as the transmitted position is not further ahead than 0.2 s (200 ms).

The various latency related parameters are summarised in Figure 1.

t

ITOATOM TOT = ITOA+TL TTOA = ITOA+CL

TL = 1.5s UL = 0.6s

(CL=TL-UL)

Figure 1: Latency Parameters

Latency should be addressed through analysis rather than testing. Total and uncompensated latency information should be generated by the respective manufacturers of the position source, ADS-B transmit unit and any interconnecting avionics and should be included as part of the latency analysis.

The latency analysis should determine the latency applicable to each component of the ADS-B Out system. The total of all of the individual component latencies should be established as the sum of their maximum latencies.

ADS-B Out systems whereby the transmit equipment compliant with AMC1 ACNS.D.ADSB.030 is directly connected to a position source compliant with AMC1 ACNS.D.ADSB.070, should meet the total latency and uncompensated latency requirements without further analysis.

For other ADS-B Out systems, the applicant should perform a detailed position and velocity latency analysis. This includes systems where ADS-B Out system components are interfaced through a highly integrated architecture.

For detailed guidance on horizontal position and velocity source latency qualification, refer to Appendix H Part 5.

CS-ACNS Issue 5 Subpart D — Surveillance (SUR)

Section 4 – 1090 MHz Extended Squitter ADS-B

Annex to EDD 2024/003/R Page 165 of 270

It is expected that this compliance information is supplied by the position and velocity source manufacturer through a Declaration of Design and Performance (DDP) or an equivalent document.

(c) ADS-B Quality Indicator Change Latency

The ADS-B Quality Indicator change latency requirements are driven by the maximum time to alert for the indication of a data integrity failure with respect to exceeding integrity containment bound (CS ACNS.D.ADSB.070 and related AMC guidance).

For detailed guidance on time to alert qualification, refer to Appendix H Part 5.

(d) Horizontal Position Latency Compensation

The ADS-B transmit unit may compensate for horizontal position latency incurred outside the ADS-B transmit unit (see sub-paragraph 2 above). If such is implemented, a verifiable estimation of the delay between the time of applicability of the position measurement, and the provision of that measurement to the ADS-B transmit unit data interface should be performed.

CS-ACNS Issue 5 Subpart D — Surveillance (SUR)

Appendices

Annex to EDD 2024/003/R Page 166 of 270

APPENDICES

Appendix A – Background information on Mode A/C surveillance systems (a) General

This Appendix provides additional references, background information, and guidance for maintenance testing, as appropriate to Mode A/C surveillance installations.

(b) Related references

(1) EASA

ETSO-C74d, Minimum Performance Standards for Airborne ATC Transponder Equipment.

(2) ICAO

(i) ICAO Annex 10, Volume IV, Aeronautical Communications (Surveillance Radar and Collision Avoidance Systems), Amdt 85;

(ii) ICAO Document 8168-OPS/611 Volume I, Procedures for Air Navigation Services, Aircraft Operations;

(iii) ICAO Document 4444-ATM/501, Procedures for Air Navigation Service, Air Traffic Management; and

(iv) ICAO EUR Regional Air Navigation Plan, Part IV, CNS Supplement SSR Code Allocation List for the EUR region, current edition.

(3) EUROCAE

(i) ED-43, Minimum Operational Performance Requirements for SSR Transponder and Alticoder; and

(ii) ED-26, Minimum Performance Specification for Airborne Altitude Measurement and Coding Systems.

(iii) EUROCAE document 1/WG9/71 June 1972 MPS for airborne secondary surveillance radar transponder apparatus - Including Amendment N°1 (measurement procedures)-April 1974 & Amendment N°2-January 2000

(4) RTCA

(i) DO-144A Minimum Operational Performance Standards (MOPS)

(c) Background information

Airborne surveillance system

The following diagram presents the Mode A and C transponder and its main functional interfaces.

CS-ACNS Issue 5 Subpart D — Surveillance (SUR)

Appendices

Annex to EDD 2024/003/R Page 167 of 270

Figure 2: Mode A/C transponder interfaces

[Issue: CS-ACNS/4]

Appendix B – Background information on Mode S ELS (a) General

This appendix provides background information on Elementary Surveillance (ELS) useful to understand ELS airborne surveillance system defined in the CS ACNS.D.ELS and its associated AMCs.

(b) Related material

(1) EASA

ETSO-C112d, Minimum Operational Performance Specification for SSR Mode S Transponders. (Based on EUROCAE ED-73E).

(2) ICAO

(i) ICAO Annex 10, Volume IV, Amd. 85, Aeronautical Communications (Surveillance Radar and Collision Avoidance Systems;)

(ii) ICAO Document 9871 Edition 2 (transponder register formats);

(iii) ICAO Document 8168-OPS/611 Volume I (Procedures for Air Navigation Services); and

(iv) ICAO Document Doc 4444-RAC/501 Procedures for Air Navigation Service, Air Traffic Management.

Mode A and C Transponder

Top antenna

Bottom antenna

Altitude source

IDENT (SPI) interface

Mode A code interface

CS-ACNS Issue 5 Subpart D — Surveillance (SUR)

Appendices

Annex to EDD 2024/003/R Page 168 of 270

(3) EUROCAE

(i) ED-73E Minimum Operational Performance Specification for Secondary Surveillance Radar Mode S Transponders; and

(ii) ED-26 Minimum Performance Specification for Airborne Altitude Measurement and Coding Systems.

(4) RTCA

RTCA DO-181E.Minimum Operational Performance Specification for Air Traffic Control Radar Beacon System/Mode Select (ATCRBS/Mode S) Airborne Equipment

(c) Background information

Airborne surveillance system description

This section describes the ELS system including transponder, interfaces, and antenna.

The following diagram represents the Mode S Transponder and its main functional interfaces.

Figure 3: Mode S ELS transponder interfaces

(1) Acquisition of aircraft position by Mode S ELS radar

Aircraft entering the coverage of a Mode S radar is first acquired by All Call interrogations to which the transponder will reply if it is not on the ground. Therefore, it is important to test that the airborne surveillance system correctly takes into account the on-the-ground information. The on-the-ground status is also used by the ACAS systems to select aircraft which will be tracked.

During this acquisition phase the radar will acquire the Horizontal position and the 24-bit aircraft address corresponding to the aircraft technical address on the RF network.

=optional feature

ELS

Mode S Transponder

Top antenna

Bottom antenna

Mode A code interface

Aircraft Identification interface

Altitude source

24 bit aircraft address

On-the – ground status

IDENT (SPI) interface

ACAS

CS-ACNS Issue 5 Subpart D — Surveillance (SUR)

Appendices

Annex to EDD 2024/003/R Page 169 of 270

The position and the aircraft address will be subsequently used to selectively interrogate the aircraft during the rest of its trajectory through the radar coverage.

Selective interrogations will be used:

(a) to update the horizontal position of the aircraft;

(b) to request the aircraft to not reply to the All Call interrogations specifically transmitted by the radar. This is known as lockout command;

(c) to request additional information such as Mode A code and altitude and

(d) to request further information to be downlinked from specific aircraft transponder registers such as the Aircraft Identification.

(2) Determination of the aircraft surveillance system capability

Ground surveillance system will need to establish the capabilities of the aircraft surveillance system to extract information only if it is available in the aircraft surveillance system. If this is not done, it could result in a situation where the aircraft would no longer reply to the interrogations used by the radar, and, therefore, the position of the aircraft could be lost. Hence, there is a need to have correct reporting of the aircraft surveillance system capability.

This process starts by determining whether the transponder is level 2 or above by checking the CA field of the Mode S All Call replies. The CA field is encoded with either 4,5,6,7 to indicate that the transponder is a level 2.

If the transponder is a level 2 or above transponder, the second step of the process is the verification of the data-link capability provided in register 1016, the ‘Data link capability report’. It contains different information about the data link capability of the airborne surveillance system

Elementary Surveillance System will use important information from this register, including:

(i) Aircraft Identification capability (bit 33 of register 1016) to determine the availability of the register containing the Aircraft Identification;

(ii) Surveillance Identifier code (bit 35 of register 1016) which indicates if SI protocol can be used to lockout the transponder; and

(iii) the Mode S Specific Services capability (bit 25 of register 1016) which indicates that Mode S specific services; including additional registers used for enhanced surveillance; are supported; and that the particular capability reports should be checked.

If the ‘Mode S Specific Services’ bit is set in register 1016, the availability of other registers will be checked by extracting register 1716.

(3) Extraction of Aircraft Identification using Mode S protocol

Aircraft equipped with Mode S having an aircraft identification feature transmits its Aircraft Identification as specified in Item 7 of the ICAO flight plan, or when no flight plan has been filed, the aircraft registration.

Aircraft Identification information will be obtained by Mode S radar by extracting the transponder register 2016 at the track initialisation.

CS-ACNS Issue 5 Subpart D — Surveillance (SUR)

Appendices

Annex to EDD 2024/003/R Page 170 of 270

The Aircraft Identification is variable when it changes from one flight to another flight. It is, therefore, possible that input errors may occur. Whenever it is observed on the ground situation display that the Aircraft Identification transmitted by a Mode S-equipped aircraft is different from that expected from the aircraft, the flight crew will be requested to confirm and, if necessary, re-enter the correct Aircraft Identification.

When Aircraft Identification is modified, the transponder will indicate this change for 18s in its selective replies. This is done using the Mode S Comm-B Broadcast protocol (ICAO Annex 10 Volume IV 3.1.2.6.11.4). The Mode S ground station will extract the Comm–B Broadcast message to obtain the new value of the Aircraft Identification.

(4) Extraction of Mode A code using Mode S protocol

Ground Mode S surveillance system will extract Mode A code at track initialisation.

If the Mode A code is modified, the transponder will indicate this change for 18s in its selective replies. This is done by raising an alert bit which is set for 18s after the change. Once this alert is detected, the Mode S ground stations will extract the new Mode A code.

It is, therefore important, that the change of the Mode A code happens on the active transponder which is announcing the change for 18s.

Note: ED-73E contains additional requirement requiring the announcement of a Mode A code change when a transponder becomes active. This is not necessarily available on older Mode S transponders in which it may be necessary to follow a specified procedure on installations with no common control interface. In some instances, a ground system workaround, consisting of periodically extracting the Mode A code, has also been implemented.

(5) ACAS Resolution Advisory (RA) report extraction

When a resolution advisory has been produced, the transponder announces the presence of a ‘RA report’ for the time that the RA is active until 18s after it has ceased. The Mode S ground stations will extract the register 3016 to obtain the information

(6) Summary of registers used for ELS

Register 1016 to obtain information on data link capability of the airborne surveillance system.

Register 1716 to obtain information on additional services available. For ELS, it is possible that register 1716 is empty (=0).

Register 2016 to obtain the Aircraft Identification.

Register 3016 to obtain the RA Report

(7) Information on Mode S replies used to support ELS

The following Mode S reply types are used to track the aircraft and obtain additional data:

DF11: Mode S All Call replies containing the 24-bit Aircraft Address and the CA field indicating whether the transponder is level 2 or greater and whether the aircraft is on the ground or airborne. DF11 can also be spontaneously transmitted as acquisition squitters. These replies are used for aircraft acquisition.

DF4: Short Mode S reply containing Altitude information.

DF5: Short Mode S reply containing the selected Mode A code.

CS-ACNS Issue 5 Subpart D — Surveillance (SUR)

Appendices

Annex to EDD 2024/003/R Page 171 of 270

DF20: Long Mode S reply containing the Altitude information and the content of the transponder register requested.

DF21: Long Mode S reply containing the Mode A code and the content of the transponder register requested.

[Issue: CS-ACNS/4]

Appendix C – Background information on Mode S EHS (a) Introduction

This appendix provides background information on Enhanced Surveillance (EHS) useful to understand EHS airborne surveillance system defined in the CS ACNS.D.EHS and its associated AMCs.

(b) Related material

(1) EASA

ETSO-C112d, Minimum Operational Performance Specification for SSR Mode S Transponders. (Based on EUROCAE ED-73E).

(2) EUROCONTROL

(i) The Concept of Operations - Mode S in Europe, document SUR.ET2.ST02.1000- CNP-01-00, Edition 2, Nov 1996:

(ii) Operational Hazard Assessment of Elementary and Enhanced Surveillance, Edition 1.1, EATMP Infocentre Reference: 04/04/07-01, 07.04.2004; and

(iii) Preliminary System Safety Analysis for the Controller Access Parameter service delivered by Mode S Enhanced Surveillance, Edition 1.1, EATMP Infocentre Reference: 04/04/07-02, 07.04.2004

(3) ICAO

(i) ICAO Annex 10, Volume IV, Amd. 85, Aeronautical Communications (Surveillance Radar and Collision Avoidance Systems; )

(ii) ICAO Document 9871 Edition 2;

(iii) ICAO Document 8168-OPS/611 Volume I (Procedures for Air Navigation Services); and

(iv) ICAO Document Doc 4444-RAC/501 Procedures for Air Navigation Service, Air Traffic Management.

(4) EUROCAE

(i) ED-73E Minimum Operational Performance Specification for Secondary Surveillance Radar Mode S Transponders;

(ii) ED-26 Minimum Performance Specification for Airborne Altitude Measurement and Coding Systems; and

(iii) ED-12C Software Considerations in Airborne Systems and Equipment Certification.

CS-ACNS Issue 5 Subpart D — Surveillance (SUR)

Appendices

Annex to EDD 2024/003/R Page 172 of 270

(5) RTCA

DO-181E Minimum Operational Performance Specification for Air Traffic Control Radar Beacon System/ Mode Select (ATCRBS/Mode S) Airborne Equipment.

(c) Background information

(1) Airborne surveillance system description

This section describes the EHS system including transponder, interfaces, and antenna.

The following diagram represents the Mode S Transponder, and its main functional interfaces. It is to be noted that different interfaces coming from different parts of the avionics may need to be connected to the transponder to support EHS.