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

ED Decision 2013/031/R

(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 data link services;

(3) for the flight crew to know in real time the identifier of the ATS provider(s) 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.

AMC1 ACNS.B.DLS.B1.010 Flight deck interface

ED Decision 2022/008/R

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 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, 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 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, 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 ATS should remain displayed until responded, cleared or 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.

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 shall be provided to the pilot to indicate the presence of 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.

[Issue: CS-ACNS/4]

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

ED Decision 2013/031/R

(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 mean is provided to distinguish between the alerting scheme in a format that is easy to comprehend.

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

ED Decision 2013/031/R

Note: A Dual stack system is either a bilingual system capable of automatically selecting the data link network or a dual system that use 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 evaluate 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: 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), 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 of ED 122, which is consistent with Doc 4444, 15th Ed, 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 significant operational capability.  Examples of different modes of data link may include situations when 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 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 aircraft does not hold two simultaneous active CPDLC connections.

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