Appendix F Table F-24. Supplemental Downlink Messages (SUPD) Operational Definition in PANS-ATM (Doc 4444) CPDLC Message Sets Message Element Identifier Message Element Intended Use Format for Message Element Display Resp. FANS 1/A ATN B1 SUPD-1 Indication that the associated message is issued due to specified reason.
DUE TO (specified reason downlink) N DM65 DUE TO
WEATHER DM65 DUE TO
WEATHER SUPD-1 Indication that the associated message is issued due to specified reason.
DUE TO (specified reason downlink) N DM66 DUE TO
AIRCRAFT
PERFORMANCE DM66 DUE TO
AIRCRAFT
PERFORMANCE Table F-25. Free Text Uplink Messages (TXTU) Operational Definition in PANS-ATM (Doc 4444) CPDLC Message Sets Message Element Identifier Message Element Intended Use Format for Message Element Display Resp. FANS 1/A ATN B1 TXTU-1 (free text) Note: M alert attribute.
R UM169 (free text) UM203 (free text) TXTU-2 (free text) Note: M alert attribute.
N UM169 (free text) Note: R response attribute.
UM183 (free text) TXTU-3 (free text) Note: N alert attribute.
N UM169 (free text) Note: R response attribute.
N/A TXTU-4 (free text) Note: M alert attribute.
W/U UM169 (free text) Note: R response attribute.
UM196 (free text) TXTU-5 (free text) Note: M alert attribute.
A/N UM169 (free text) Note: R response attribute.
UM205 (free text) F-49
Appendix F Table F-26. Free Text Downlink Messages (TXTD) Operational Definition in PANS-ATM (Doc 4444) CPDLC Message Sets Message Element Identifier Message Element Intended Use Format for Message Element Display Resp. FANS 1/A ATN B1 TXTD-1 (free text) Note: M alert attribute.
Y DM68 (free text) Note 1: Urgency or Distress Alr (M).
Note 2: Selecting any of the emergency message elements will result in this message element being enabled for the pilot to include in the emergency message at their discretion.
N/A TXTD-2 (free text) Note: M alert attribute.
N DM67 (free text) DM98 (free text) F-50
Appendix F Table F-27. System Management Uplink Messages (SYSU) Operational Definition in PANS-ATM (Doc 4444) CPDLC Message Sets Message Element Identifier Message Element Intended Use Format for Message Element Display Resp. FANS 1/A ATN B1 SYSU-1 System-generated notification of an error.
ERROR (error information) N UM159 ERROR (error information) UM159 ERROR (error information) SYSU-2 System-generated notification of the next data authority or the cancellation thereof.
NEXT DATA AUTHORITY (facility designation[O]) N UM160 NEXT
DATA AUTHORITY (ICAO facility designation) Note: The facility designation is required.
UM160 NEXT DATA
AUTHORITY (facility) Note: Facility parameter can specify a facility designation or no facility.
SYSU-3 System-generated notification that received message is not supported.
MESSAGE NOT
SUPPORTED BY THIS ATC UNIT N UM169 ‘MESSAGE
NOT SUPPORTED
BY THIS ATC UNIT’ Note: R response attribute.
UM162 MESSAGE NOT
SUPPORTED BY THIS
ATS UNIT SYSU-4 System-generated notification that the received is acceptable for display.
LOGICAL
ACKNOWLEDGEMENT N N/A UM227 LOGICAL
ACKNOWLEDGEMENT SYSU-5 System-generated message indicating that requests for logical acknowledgements are not permitted.
USE OF LOGICAL
ACKNOWLEDGEMENT
PROHIBITED N N/A UM233 USE OF LOGICAL
ACKNOWLEDGEMENT
PROHIBITED Note: ATN B1 ground systems may not use UM (as par ETSI CS) since the use of LACK is required.
F-51
Appendix F Operational Definition in PANS-ATM (Doc 4444) CPDLC Message Sets Message Element Identifier Message Element Intended Use Format for Message Element Display Resp. FANS 1/A ATN B1 SYSU-6 Advisory providing the maximum one-way uplink message transmission delay.
LATENCY TIME VALUE (latency value) N UM169 ‘SET MAX
UPLINK DELAY VALUE TO (delayed message parameter) SECONDS’ Note 1: R response attribute.
Note 2: On FANS 1/A aircraft, this message requires specific action from the pilot to manually set the latency value.
N/A SYSU-7 Indication that the received message has a latency greater than the requirement.
MESSAGE RECEIVED TOO
LATE, RESEND MESSAGE
OR CONTACT BY VOICE N N/A UM159 ERROR (error information) + UM183 ‘DOWNLINK DELAYED USE – VOICE’ Note: The error information is set to the value (2).
F-52
Appendix F Table F-28. System Management Downlink Messages (SYSD) Operational Definition in PANS-ATM (Doc 4444) CPDLC Message Sets Message Element Identifier Message Element Intended Use Format for Message Element Display Resp. FANS 1/A ATN B1 SYSD-1 System-generated notification of an error.
ERROR (error information) N DM62 ERROR (error information) DM62 ERROR (error information) SYSD-2 System-generated notification that the received message is acceptable for display.
LOGICAL
ACKNOWLEDGEMENT N N/A DM100 LOGICAL
ACKNOWLEDGEMENT SYSD-3 System-generated rejection of any CPDLC message sent from a ground facility that is not the current data authority.
NOT CURRENT DATA
AUTHORITY N DM63 NOT CURRENT
DATA AUTHORITY DM63 NOT CURRENT
DATA AUTHORITY SYSD-4 System-generated notification that the ground facility is now the current data authority.
CURRENT DATA
AUTHORITY N N/A DM99 CURRENT DATA
AUTHORITY SYSD-5 System-generated notification that the ground system is not designated as the next data authority (NDA), indicating the identity of the Current Data Authority. Identity of the Next Data Authority, if any, is also reported.
NOT AUTHORIZED NEXT
DATA AUTHORITY (facility designation) (facility designation[O]) N DM64 (ICAO facility designation) Note: Use by FANS 1/A aircraft in B1 environments.
DM107 NOT AUTHORIZED
NEXT DATA AUTHORITY Note: CDA and NDA cannot be provided.
SYSD-6 Indication that the received message has a latency greater than the requirement.
MESSAGE RECEIVED TOO
LATE, RESEND MESSAGE
OR CONTACT BY VOICE N DM67 ‘MESSAGE
RECEIVED TOO
LATE, RESEND
MESSAGE OR
CONTACT BY VOICE’ Note: Sent with DM62.
DM 98 ‘MESSAGE
RECEIVED TOO LATE,
RESEND MESSAGE OR CONTACT BY VOICE’ Note: Sent with DM62.
SYSD-7 System-generated notification that the aircraft is in the inhibited state.
AIRCRAFT CPDLC
INHIBITED N N/A DM 98 ‘AIRCRAFT CPDLC
INHIBITED' F-53
Appendix F Table F-29. FANS 1/A Uplink Messages Not Recommended for Use Message Element Justification UM49 CROSS (position) AT AND MAINTAIN (altitude) Avoid use of this message due to inability of aircraft automation to maintain the altitude restriction.
UM62 AT (time) CROSS (position) AT AND MAINTAIN (altitude) Avoid use of this message due to inability of aircraft automation to maintain the altitude restriction.
UM85 EXPECT (route clearance) Avoid use of this message element due to potential misinterpretation.
UM86 AT (position) EXPECT (route clearance) Avoid use of this message element due to potential misinterpretation.
UM87 EXPECT DIRECT TO (position) Avoid use of this message element due to potential misinterpretation.
UM88 AT (position) EXPECT DIRECT TO (position) Avoid use of this message element due to potential misinterpretation.
UM89 AT (time) EXPECT DIRECT TO (position) Avoid use of this message element due to potential misinterpretation.
UM90 AT (altitude) EXPECT DIRECT TO (position) Avoid use of this message element due to potential misinterpretation.
UM162 SERVICE UNAVAILABLE Avoid use of this message element due to potential misinterpretation.
UM6 EXPECT (altitude) Avoid use of this message element due to potential misinterpretation.
UM11 EXPECT CRUISE CLIMB AT (time) Avoid use of this message element due to potential misinterpretation.
UM12 EXPECT CRUISE CLIMB AT (position) Avoid use of this message element due to potential misinterpretation.
UM13 AT (time) EXPECT CLIMB TO (altitude) Avoid use of this message element due to potential misinterpretation.
UM14 AT (position) EXPECT CLIMB TO (altitude) Avoid use of this message element due to potential misinterpretation.
UM15 AT (time) EXPECT DESCENT TO (altitude) Avoid use of this message element due to potential misinterpretation.
UM16 AT (position) EXPECT DESCENT TO (altitude) Avoid use of this message element due to potential misinterpretation.
UM17 AT (time) EXPECT CRUISE CLIMB TO (altitude) Avoid use of this message element due to potential misinterpretation.
UM49 CROSS (position) AT AND MAINTAIN (altitude) Avoid use of this message element due to potential misinterpretation.
UM62 AT (time) CROSS (position) AT AND MAINTAIN (altitude) Avoid use of this message element due to potential misinterpretation.
UM18 AT (position) EXPECT CRUISE CLIMB TO (altitude) Avoid use of this message element due to potential misinterpretation.
UM33 CRUISE (altitude) Avoid use of this message element due to potential misinterpretation.
UM34 CRUISE CLIMB TO (altitude) Avoid use of this message element due to potential misinterpretation.
F-54
Appendix F Message Element Justification UM35 CRUISE CLIMB ABOVE (altitude) Avoid use of this message element due to potential misinterpretation.
UM40 IMMEDIATELY STOP CLIMB AT (altitude) Avoid use of this message element due to potential misinterpretation.
UM41 IMMEDIATELY STOP DESCENT AT (altitude) Avoid use of this message element due to potential misinterpretation.
UM175 REPORT REACHING (altitude) Avoid use of this message element due to potential misinterpretation.
UM42 EXPECT TO CROSS (position) AT (altitude) Avoid use of this message element due to potential misinterpretation.
UM43 EXPECT TO CROSS (position) AT OR ABOVE (altitude) Avoid use of this message element due to potential misinterpretation.
UM44 EXPECT TO CROSS (position) AT OR BELOW (altitude) Avoid use of this message element due to potential misinterpretation.
UM45 EXPECT TO CROSS (position) AT AND MAINTAIN (altitude) Avoid use of this message element due to potential misinterpretation.
UM103 AT (time) EXPECT (speed) TO (speed) Avoid use of this message element due to potential misinterpretation.
UM104 AT (position) EXPECT (speed) TO (speed) Avoid use of this message element due to potential misinterpretation.
UM105 AT (altitude) EXPECT (speed) TO (speed) Avoid use of this message element due to potential misinterpretation.
UM165 THEN Avoid use of this message element due to potential misinterpretation.
UM235 ROGER 7500 Avoid use of this message element due to potential misinterpretation.
UM168 DISREGARD Not operationally required.
Note: These messages have been excluded from future B2 implementation.
UM176 MAINTAIN OWN SEPARATION AND VMC Not operationally required.
Note: These messages have been excluded from future B2 implementation.
UM152 WHEN CAN YOU ACCEPT (specified distance) (direction) OFFSET Not operationally required.
Note: These messages have been excluded from future B2 implementation.
UM115 DO NOT EXCEED (speed) Not operationally required.
Note: These messages have been excluded from future B2 implementation.
UM182 CONFIRM ATIS CODE Not operationally required.
Note: These messages have been excluded from future B2 implementation.
UM169 ‘TRANSMIT ADS-B IDENT’ Use of SQUAWK IDENT is recommended.
UM169 ‘IDENTIFICATION TERMINATED’ Use of SURVEILLANCE SERVICE TERMINATED is recommended.
UM132 CONFIRM POSITION Use of ADS-C is recommended.
UM133 CONFIRM ALTITUDE Use of ADS-C is recommended.
F-55
Appendix F Message Element Justification UM138 CONFIRM TIME OVER REPORTED WAYPOINT. Use of ADS-C is recommended.
UM139 CONFIRM REPORTED WAYPOINT Use of ADS-C is recommended.
UM140 CONFIRM NEXT WAYPOINT Use of ADS-C is recommended.
UM141 CONFIRM NEXT WAYPOINT ETA. Use of ADS-C is recommended.
UM142 CONFIRM ENSUING WAYPOINT Use of ADS-C is recommended.
UM146 REPORT GROUND TRACK Use of ADS-C is recommended.
UM181 REPORT DISTANCE (to/from) (position) Use of ADS-C is recommended.
UM145 CONFIRM HEADING Use of ADS-C is recommended.
UM177 AT PILOTS DISCRETION Not globally accepted. In airspace managed by the United States, when the controller issues UM177 AT PILOTS DISCRETION in conjunction with altitude assignments, the associated instruction to climb or descend may be executed when convenient and at any preferred rate. The aircraft may temporarily maintain intermediate levels but once the aircraft has vacated a level it may not return to that level.
F-56
Appendix F Table F-30. FANS 1/A Downlink Messages Not Recommended for Use Message Element Justification DM69 REQUEST VMC DESCENT Avoid use of this message element due to potential misinterpretation DM75 AT PILOTS DISCRETION Avoid use of this message element due to potential misinterpretation DM 67 ‘WHEN CAN WE EXPECT DESCENT TO (altitude)’ Avoid use of this message due to potential misinterpretation of subsequent response. Use of LVLD-6 WHEN CAN WE EXPECT LOWER LEVEL and LVLD-7 WHEN CAN WE EXPECT HIGHER LEVEL is recommended.
DM67 ‘WHEN CAN WE EXPECT CLIMB TO (altitude)’ Avoid use of this message due to potential misinterpretation of subsequent response. Use of LVLD-6 WHEN CAN WE EXPECT LOWER LEVEL and LVLD-7 WHEN CAN WE EXPECT HIGHER LEVEL is recommended.
DM74 REQUEST TO MAINTAIN OWN SEPARATION AND VMC Not operationally required.
Note: These messages have been excluded from future B2 implementation.
DM8 REQUEST CRUISE CLIMB TO (altitude) Not operationally required.
Note: These messages have been excluded from future B2 implementation.
DM54 WHEN CAN WE EXPECT CRUISE CLIMB TO (altitude) Not operationally required.
Note: These messages have been excluded from future B2 implementation.
DM72 REACHING (altitude) Not operationally required.
Note: These messages have been excluded from future B2 implementation.
DM79 ATIS (ATIS code) Not operationally required.
Note: These messages have been excluded from future B2 implementation.
DM67 ‘MONITORING (unit name) (frequency)’ Not operationally required.
Note: These messages have been excluded from future B2 implementation.
DM16 AT (position) REQUEST OFFSET (specified distance) (direction) OF ROUTE Not operationally required.
Note: These messages have been excluded from future B2 implementation.
DM17 AT (time) REQUEST OFFSET (specified distance) (direction) OF ROUTE Not operationally required.
Note: These messages have been excluded from future B2 implementation.
DM26 REQUEST WEATHER DEVIATION TO (position) VIA (route clearance) Not operationally required.
Note: These messages have been excluded from future B2 implementation.
DM33 PRESENT POSITION (position) Use of ADS-C is recommended.
DM36 PRESENT GROUND TRACK (degrees) Use of ADS-C is recommended.
F-57
Appendix F Message Element Justification DM42 NEXT WAYPOINT (position) Use of ADS-C is recommended.
DM43 NEXT WAYPOINT ETA (time) Use of ADS-C is recommended.
DM44 ENSUING WAYPOINT (position) Use of ADS-C is recommended.
DM45 REPORTED WAYPOINT (position) Use of ADS-C is recommended.
DM46 REPORTED WAYPOINT (time) Use of ADS-C is recommended.
DM78 AT (time) (distance) (to/from) (position) Use of ADS-C is recommended.
DM32 PRESENT ALTITUDE (altitude) Use of ADS-C is recommended.
DM35 PRESENT HEADING (degrees) Use of ADS-C is recommended.
DM19 REQUEST (speed) TO (speed) Use of SPDD-1 REQUEST (speed) is recommended.
DM50 WHEN CAN WE EXPECT (speed) TO (speed) Use of SPDD-1 REQUEST (speed) is recommended.
Table F-31. ATN B1 Uplink Messages Not Recommended for Use Message Element Justification UM165 THEN Avoid use of this message element due to potential misinterpretation.
Table F-32. ATN B1 Downlink Messages Not Recommended for Use Message Element Justification DM89 MONITORING (unit name) (frequency) Not operationally required.
Note: This message has been excluded from future B2 implementation.
F-58
Appendix G AP PENDIX G. TERMINOLOGY AND ACRONYMS G.
1 Terminology.
1. Aeronautical Telecommunications Network (ATN). A global inter-network architecture that allows ground, air-ground, and avionic data subnetworks to exchange digital data for the safety of air navigation and for the regular, efficient, and economic operation of Air Traffic Services (ATS).
2. Air Navigation Services Provider (ANSP). An organization responsible for the provision of ATS.
3. Air Traffic Data Link Service. A data communication capability comprising air/ground and ground/ground data network services, specified data link message sets and protocols, aircraft equipment, Air Traffic Service Unit (ATSU) facility equipment, and operational procedures intended to provide primary or supplemental ATSU communications.
4. Air Traffic Service Unit (ATSU). This domain includes the controller and the ATSU system which consists of an end system where data communications applications reside, a ground to ground router, a ground to ground communication network, and human-machine interface (HMI).
5. Aircraft Communications Addressing and Reporting System (ACARS). ACARS is a digital data link system for transmission of short messages between aircraft and ground stations via airband radio or satellite. ACARS as a term refers to the complete air and ground system, consisting of a service provider and aircraft/ground equipment.
6. Allocations. For approval, design, and monitoring purposes, performance requirements are provided against allocated human and technical Air Traffic System Management (ATM)/Communication, Navigation, and Surveillance (CNS) elements
(i.e., the aircraft system, aircraft operator, ANSP, and Communication Service Provider (CSP)) of the data communications transaction.
7. Automatic Dependent Surveillance-Contract (ADS-C). ADS-C is a surveillance information system using automated reports. An agreement is established between the ground system and the aircraft via a data link. Without pilot input, the ATSU can establish a “contract” to provide reports of aircraft position, altitude, speed, elements of navigational intent, and meteorological data. The system can generate the following types of reports:
• Demand: An ATSU can request an update as needed, and this does not affect an existing contact preset rate.
• Event: A change in vertical rate, lateral deviation, or altitude automatically triggers a report.
• Periodic: The ATSU can set or alter the update rate as needed (a higher update rate is usually required in high traffic areas or with reduced lateral separations).
G-1
Appendix G
8. Availability. The probability that an operational communication transaction can be initiated when needed.
9. Communication Transaction Time. The maximum time for the completion of the operational communication transaction, after which the initiator should revert to an alternative procedure.
10. Continuity. The probability that an operational communication transaction can be completed within the communication transaction time.
11. Controller-Pilot Data Link Communications (CPDLC). CPDLC is a two-way data-link communication system by which controllers can transmit digital text messages to an aircraft as an alternative to voice communications. Messages from an aircraft to the ATSU may follow a standard format or may be free text. Messages from a controller normally follow a standard format and usually require a response from the pilot.
12. Current Data Authority (CDA). The designated ground system through which a CPDLC dialogue between a pilot and a controller currently responsible for the flight is permitted to take place.
13. Data Link Communication System. A data link communication system is a means of transmitting and receiving digital information. “Data link” is a generic term that encompasses different types of data link communication systems and subnetworks.
14. Departure Clearance (DCL). DCL (CPDLC-DCL) is the initial phase of U.S. domestic airspace implementation of data communication and is limited to tower services. CPDLC-DCL provides automated assistance for requesting and delivering initial and revised DCLs using CPDLC. The DCL includes flight plan route, climb via and/or initial/requested altitude, beacon code assignment, and departure frequency.
15. Downlink Message (DM). A CPDLC message sent from an aircraft.
16. Future Air Navigation System (FANS). FANS is an avionics system which provides direct data link communication between the pilot and the air traffic controller. The communications include air traffic control (ATC) clearances, pilot requests, and Position Reporting (PR).
17. Integrity. The probability of one or more undetected errors in a completed communication transaction.
18. Maximum Accumulated Unplanned Outage Time. A value that defines the acceptable accumulated duration of unplanned outages that exceed the unplanned outage duration limit in a specified time period.
Note: Unplanned outages that are less than the unplanned outage duration limit are considered against the criterion for continuity.
G-2