ENR 7.2 Data Link Procedures

1.. Oakland Oceanic Airspace

  1. Oakland ARTCC has full CPDLC and ADS-C services in the entire Oakland Oceanic FIR for FANS-1/A ­capable aircraft. The Oakland Oceanic FIR log-on address is “KZAK;" the facility is “OAKODYA." CADS ­LOGON is not supported.
  2. The use of CPDLC and ADS-C in the Oakland Oceanic FIR (KZAK) is only permitted by Inmarsat and ­Iridium customers. All other forms of data link connectivity are not authorized. If J5 (Inmarsat) or J7 (Iridium) ­is not included in the ICAO FPL Item 10a, then the LOGON will be rejected by KZAK and the aircraft will not ­be able to connect.
  3. Prior to entering the Oakland Oceanic FIR, contact San Francisco Radio and request a SELCAL check.
    1. Regardless of aircraft ADS-C capability, aircraft without a KZAK ADS-C connection must forward a FIR ­position report and continue HF or CPDLC position reporting until a KZAK ADS-C connection is established.
  4. Determine the status of the CPDLC connection. If KZAK is the active center, the pilot must contact San ­Francisco Radio on HF for a SELCAL check.
    1. If KZAK is not the active center, the pilot must, within 5 minutes after the boundary is crossed, terminate ­the CPDLC connection, then log on to KZAK, and contact San Francisco Radio on HF for a SELCAL check.
  5. Flights overflying Honolulu Control Facility (HCF) airspace will receive an END SERVICE message prior ­to entering HCF airspace that will result in termination of CPDLC. Aircraft must re-log on to CPDLC prior to ­reentering Oakland Oceanic FIR airspace when HCF advises to contact en route communications or San ­Francisco Radio.
  6. Flights overflying Guam Combined Control Facility (CCF) airspace should maintain the CPDLC ­connection with Oakland ARTCC; however, do not use CPDLC for ATC COM until Guam CCF advises you to ­again contact en route communications or San Francisco Radio.

2.. Anchorage Oceanic Airspace

  1. Anchorage ARTCC has full CPDLC capability and normal service for FANS-1/A capable aircraft within ­INMARSAT or Iridium coverage.
    1. The Anchorage Arctic FIR logon address is “PAZN;” the facility is “ANCXFXA.” CADS LOGON is not ­supported.
    2. The Anchorage Domestic and Oceanic FIRs (South of N63 and west of W165) logon address is “PAZN;” ­the facility is “ANCATYA.” CADS LOGON is not supported.
  2. Prior to entering the Anchorage Oceanic FIR, contact San Francisco Radio and request a SELCAL check.
    1. Regardless of aircraft ADS-C capability, aircraft without a PAZN Anchorage ADS-C connection must ­forward a FIR position report and continue HF or CPDLC position reporting until an Anchorage ADS-C ­connection is established.

3.. New York Oceanic Airspace

  1. New York ARTCC provides full CPDLC and ADS-C services throughout its Oceanic Airspace to ­FANS-1/A capable flights. The New York Oceanic FIR FANS LOGON address is “KZWY." CADS LOGON ­is not supported. Flights should use ADS-C for position reporting and CPDLC for all other ATC communications ­while in the New York Oceanic Area.
  2. The use of CPDLC and ADS-C in the New York Oceanic FIR (KZWY) is only permitted by Inmarsat and ­Iridium customers. Users must ensure that the proper data link code is filed in Item 10a of the ICAO. If J5 ­(Inmarsat) or J7 (Iridium) is not included in the ICAO FPL, then the LOGON will be rejected by KZWY and ­the aircraft will not be able to connect.
  3. Prior to entering the New York Oceanic FIR, contact New York Radio and request a SELCAL check.
    1. Regardless of aircraft ADS-C capability, aircraft without a KZWY ADS-C connection must forward a ­position report and continue HF or CPDLC position reporting until a KZWY ADS-C connection is established.
  4. If the flight will exit the New York Oceanic FIR into domestic airspace (including over New York Bermuda ­RADAR):
    1. Identify the flight as ADS-C and/or CPDLC connected;
    2. If operating on the North Atlantic Organized Track System (OTS), state the track letter;
    3. State the name of the next CTA/FIR to be entered along with the latitude and longitude or waypoint exit ­point leaving the New York Oceanic FIR; and
    4. Request a SELCAL check.
  5. Aircraft entering the New York Oceanic FIR from non-data link airspace should:
    1. LOGON to KZWY at least 15 minutes but not more than 45 minutes prior to entering the New York ­Oceanic FIR.
    2. Prior to entering the New York Oceanic FIR contact New York Radio on HF or VHF providing the ­information as outlined in paragraph 3.3.
  6. Aircraft entering the New York Oceanic FIR data link service area from adjacent data link airspace should:
    1. Determine the status of the FANS connection when crossing the New York Oceanic FIR boundary. CPDLC ­and ADS-C services are forwarded automatically between the New York, Santa Maria, Piarco, and Gander ­OCAs at a pre-determined time (approximately 5 minutes) from CTA/FIR boundary. CPDLC only services are ­forwarded between New York Oceanic (KZWY) and Moncton ACC.CPDLC connection (via "Next Data ­Authority") is automatically transferred between New York Oceanic (KZWY) and FAA domestic ARTCCs ­(KUSA).
      1. If KZWY is the active connection when crossing the New York Oceanic FIR boundary the pilot must:
      2. Contact New York Radio on HF providing the information as outlined in paragraph 3.3.
    2. If KZWY is not the active center when crossing the New York Oceanic FIR boundary the pilot must:
      1. Terminate the CPDLC connection, then log-on to KZWY; and
      2. Contact New York Radio on HF providing the information as outlined in paragraph 3.3.
  7. Aircraft exiting the KZWY data link service area and approaching the New York Center Domestic, New ­York Center Bermuda RADAR, San Juan, Piarco, Jacksonville, Miami, Moncton, and Gander Domestic can ­expect a CPDLC uplink message containing the VHF frequency assignment for the next facility. CPDLC End ­Service will be sent approximately 5 minutes prior to the boundary crossing point.

4.. Data Link Failure

  1. In the event of data link failure or outages, flight crews must contact New York Radio or San Francisco Radio ­via HF voice for routine communications. When unable to communicate on HF, the pilot may conduct normal ­and routine communications with ATC via New York Radio or San Francisco Radio on SATVOICE. Direct ­SATVOICE contact with ATC should be limited to distress and urgency situations or when other means are not ­available and communication is essential.

5.. CPDLC Uplink Message Latency Monitor Function

  1. Oakland (KZAK), Anchorage (PAZN) and New York (KZWY) request pilots activate the CPDLC uplink ­message latency monitor function to help prevent pilots from acting on a CPDLC uplink message that has been ­delayed in the network. When flights enter oceanic data link airspace, or initiate AFN log on within their oceanic ­data link airspace, equipped flights will receive a message advising crews to set the latency value. “SET MAX ­UPLINK DELAY VALUE TO 300 SEC”
  2. When pilots receive the CPDLC uplink message “SET MAX UPLINK DELAY VALUE 300 SEC”, they ­must acknowledge ("ROGER") the uplink as prompted by the avionics, regardless of whether the aircraft ­supports the latency monitor.
  3. If the aircraft is equipped with a correctly functioning message latency monitor, enter the specified uplink ­delay into the avionics in accordance with the aircraft procedures. Some avionics will automatically set the delay ­value in accordance with the uplink message and do not allow for a manual input.
  4. When pilots receive a latency monitor indication that a CPDLC uplink message has been delayed, the pilots ­shall:
    1. Revert to voice communications to notify the ATS unit of the delayed CPDLC uplink message received, ­and to request clarification of the intent of the message.
    2. Respond appropriately to close the message as per the instructions of the controller.
    3. Not act on the delayed uplink message until clarification has been received from the controller.

6.. CPDLC Messages In Use in the Oakland, Anchorage, and New York Oceanic Airspace

  1. The CPDLC messages that are in use and authorized in the oceanic airspace of Oakland, Anchorage, and ­New York ARTCCs are shown in TBL ENR 7.2-1 through TBL ENR 7.2-26.
    TBL ENR 7.2-1Response Attribute of CPDLC Message Element

    Response
    Attribute

    Description

    For Uplink Message

    W/U

    Response required.Valid responses. WILCO, UNABLE, STANDBY, NOT CURRENT DATA AUTHORITY, ­NOT AUTHORIZED NEXT DATA AUTHORITY, LOGICAL ACKNOWLEDGEMENT ­(only if required), ERRORNote – WILCO, UNABLE, NOT CURRENT DATA AUTHORITY, NOT AUTHORIZED NEXT ­DATA AUTHORITY and ERROR will close the uplink message.
    FANS 1/A.– WILCO, UNABLE, STANDBY, ERROR, NOT CURRENT DATA AUTHORITY.

    A/N

    Response required.Valid responses. AFFIRM, NEGATIVE, STANDBY, NOT CURRENT DATA AUTHORITY, ­NOT AUTHORIZED NEXT DATA AUTHORITY, LOGICAL ACKNOWLEDGEMENT ­(only if required), ERRORNote – AFFIRM, NEGATIVE, NOT CURRENT DATA AUTHORITY, NOT AUTHORIZED ­NEXT DATA AUTHORITY and ERROR will close the uplink message.
    FANS 1/A.– AFFIRM, NEGATIVE, STANDBY, ERROR, NOT CURRENT DATA AUTHORITY.

    R

    Response required.Valid responses. ROGER, UNABLE, STANDBY, NOT CURRENT DATA AUTHORITY, ­NOT AUTHORIZED NEXT DATA AUTHORITY, LOGICAL ACKNOWLEDGEMENT ­(only if required), ERRORNote – ROGER, NOT CURRENT DATA AUTHORITY, NOT AUTHORIZED NEXT DATA AU­THORITY and ERROR will close the uplink message. FANS 1/A.– ROGER, STANDBY, ERROR, NOT CURRENT DATA AUTHORITY. FANS 1/A ­aircraft do not have the capability to send UNABLE in response to an uplink message contain­ing message elements with an “R” response attribute. For these aircraft, the flight crew may ­use alternative means to UNABLE the message. These alternative means will need to be taken ­into consideration to ensure proper technical and operational closure of the communication ­transaction.

    Y

    Response required.Valid responses: Any CPDLC downlink message, LOGICAL ACKNOWLEDGEMENT (only ­if required).

    N

    No response required unless logical acknowledgement is required.Valid Responses (only if LOGICAL ACKNOWLEDGEMENT is required). LOGICAL AC­KNOWLEDGEMENT, NOT CURRENT DATA AUTHORITY, NOT AUTHORIZED NEXT ­DATA AUTHORITY, ERRORFANS 1/A.– “N” is defined as “no response is required,” but not used. Under some circum­stances, an ERROR message will also close an uplink message.

    NE

    [Not defined in Doc 4444] FANS 1/A.– The WILCO, UNABLE, AFFIRM, NEGATIVE, ROGER, and STANDBY responses ­are not enabled (NE) for flight crew selection. An uplink message with a response attribute NE ­is considered to be closed even though a response may be required operationally. Under some ­circumstances, a downlink error message may be linked to an uplink message with a NE at­tribute.

    For Downlink Message

    Y

    Response required. YesValid responses. Any CPDLC uplink message, LOGICAL ACKNOWLEDGEMENT (only if ­required).

    N

    Response required. No, unless logical acknowledgement required.Valid responses (only if LOGICAL ACKNOWLEDGEMENT is required). LOGICAL AC­KNOWLEDGEMENT, SERVICE UNAVAILABLE, FLIGHT PLAN NOT HELD, ERROR FANS 1/A.– Aircraft do not have the capability to receive technical responses to downlink mes­sage elements with an “N” response attribute (other than LACK or ERROR for ATN B1 air­craft). In some cases, the response attribute is different between FANS 1/A aircraft and Doc ­4444. As an example, most emergency messages have an “N” response attribute for FANS 1/A ­whereas Doc 4444 defines a “Y” response attribute for them. As a consequence, for FANS 1/A ­aircraft, ATC will need to use alternative means to acknowledge to the flight crew that an ­emergency message has been received.

    TBL ENR 7.2-2Route Uplink Message Elements (RTEU)

    CPDLC Message Sets

    Operational Definition in PANS-ATM (Doc 4444)

    FANS 1/A

    ATN B1

    Response

    Message
    Element
    Identifier

    Message Element ­Intended Use

    Format for
    Message Element ­Display

    UM74 PROCEED ­DIRECT TO
    (position)

    UM74 PROCEED ­DIRECT TO
    (position)

    W/U

    RTEU-2

    Instruction to pro­ceed directly to the ­specified position.

    PROCEED DI­RECT TO (posi­tion)

    UM75 WHEN ­ABLE PROCEED ­DIRECT TO (posi­tion)
    Note – This mes­sage element is ­equivalent to ­SUPU-5 plus ­RTEU-2 in Doc ­4444.

    N/A

    W/U

    RTEU-2

    Instruction to pro­ceed directly to the ­specified position.

    PROCEED DI­RECT TO (posi­tion)

    UM76 AT (time) ­PROCEED DI­RECT TO (posi­tion)

    N/A

    W/U

    RTEU-3

    Instruction to pro­ceed, at the speci­fied time, directly to ­the specified posi­tion.

    AT TIME (time) ­PROCEED DI­RECT TO (posi­tion)

    UM77 AT (posi­tion) PROCEED ­DIRECT TO (posi­tion)

    N/A

    W/U

    RTEU-4

    Instruction to pro­ceed, at the speci­fied position, direct­ly to the next speci­fied position.

    AT (position) PRO­CEED DIRECT TO ­(position)

    UM78 AT (altitude) ­PROCEED DI­RECT TO (posi­tion)

    N/A

    W/U

    RTEU-5

    Instruction to pro­ceed upon reaching ­the specified level, ­directly to the spec­ified position.

    AT (level single) ­PROCEED DI­RECT TO (posi­tion)

    UM79 CLEARED ­TO (position) via ­(route clearance)

    UM79 CLEARED ­TO (position) via ­(route clearance)

    W/U

    RTEU-6

    Instruction to pro­ceed to the speci­fied position via the ­specified route.

    CLEARED TO (po­sition) VIA (depar­ture data[O]) (en-­route data)

    UM 80 CLEARED ­(route clearance)

    UM 80 CLEARED ­(route clearance)

    W/U

    RTEU-7

    Instruction to pro­ceed via the speci­fied route.

    CLEARED (depar­ture data[O]) (en-­route data) (arrival ­approach data)

    UM83 AT (posi­tion) CLEARED ­(route clearance)

    N/A

    W/U

    RTEU-9

    Instruction to pro­ceed from the speci­fied position via the ­specified route.

    AT (position) ­CLEARED (en-­route data) (arrival ­approach data)

    UM85 EXPECT ­(route clearance)

    N/A

    R

    N/A

    Notification that a ­clearance to fly on ­the specified route ­may be issued.

    N/A

    UM86 AT (posi­tion) EXPECT ­(route clearance)

    N/A

    R

    N/A

    Notification that a ­clearance to fly on ­the specified route ­from the specified ­position may be is­sued.

    N/A

    UM87 EXPECT ­DIRECT TO (posi­tion)

    N/A

    R

    N/A

    Notification that a ­clearance to fly di­rectly to the speci­fied position may ­be issued.

    N/A

    UM88 AT (posi­tion) EXPECT DI­RECT TO (posi­tion)

    N/A

    R

    N/A

    Notification that a ­clearance to fly di­rectly from the first ­specified position to ­the next specified ­position may be is­sued.

    N/A

    UM89 AT (time) ­EXPECT DIRECT ­TO (position)

    N/A

    R

    N/A

    Notification that a ­clearance to fly di­rectly to the speci­fied position com­mencing at the ­specified time may ­be issued.

    N/A

    UM90 AT (altitude) ­EXPECT DIRECT ­TO (position)

    N/A

    R

    N/A

    Notification that a ­clearance to fly di­rectly to the speci­fied position com­mencing when the ­specified level is ­reached may be is­sued.

    N/A

    UM93 EXPECT ­FURTHER ­CLEARANCE AT ­(time)

    N/A

    R

    RTEU-13

    Notification that an ­onwards clearance ­may be issued at the ­specified time.

    EXPECT FUR­THER CLEAR­ANCE AT TIME ­(time)

    UM99 EXPECT ­(procedure name)

    Note – Used when a ­published proce­dure is designated.

    N/A

    R

    RTEU-14

    Notification that a ­clearance may be ­issued for the air­craft to fly the spec­ified procedure or ­clearance name.

    EXPECT (named ­instruction)

    UM137 CONFIRM ­ASSIGNED ­ROUTE

    Note – NE response ­attribute.

    N/A

    Y

    RTEU-15

    Request to confirm ­the assigned route.

    CONFIRM AS­SIGNED ROUTE

    UM147 REQUEST ­POSITION RE­PORT

    N/A

    Y

    RTEU-16

    Request to make a ­position report.

    REQUEST POSI­TION REPORT

    TBL ENR 7.2-3Route Downlink Message Elements (RTED)

    CPDLC Message Sets

    Operational Definition in PANS-ATM (Doc 4444)

    FANS 1/A

    ATN B1

    Response

    Message ­Element ­Identifier

    Message Element ­Intended Use

    Format for Mes­sage Element Dis­play

    DM22 REQUEST ­DIRECT TO (posi­tion)

    DM22 REQUEST ­DIRECT TO (posi­tion)

    Y

    RTED-1

    Request for a direct ­clearance to the ­specified position.

    REQUEST DI­RECT TO (posi­tion)

    DM23 REQUEST ­(procedure name)

    N/A

    Y

    RTED-2

    Request for the ­specified route.

    REQUEST (named ­instruction)

    DM24 REQUEST ­(route clearance)

    N/A

    Y

    RTED-3

    Request for the ­specified procedure ­or clearance name.

    REQUEST ­CLEARANCE (de­parture data[O]) ­(en-route data)(ar­rival approach da­ta[O])

    DM25 REQUEST ­CLEARANCE

    N/A

    Y

    RTED-4

    Request for the ­specified clearance.

    REQUEST (clear­ance type) ­CLEARANCE

    DM26 REQUEST ­WEATHER DEVI­ATION TO (posi­tion) VIA (route ­clearance)

    N/A

    Y

    N/A

    Request for a ­weather deviation ­to the specified po­sition via the speci­fied route.

    N/A

    DM40 ASSIGNED ­ROUTE (route ­clearance)

    N/A

    Y

    RTED-9

    Confirmation that ­the assigned route ­is the specified ­route.

    ASSIGNED ­ROUTE (departure ­data[O]) (en-route ­data) (arrival ap­proach data[O])

    DM40 ASSIGNED ­ROUTE (route ­clearance)

    N/A

    N

    RTED-9

    Confirmation that ­the assigned route ­is the specified ­route.

    ASSIGNED ­ROUTE (departure ­data[O]) (en-route ­data) (arrival ap­proach data[O])

    DM48 POSITION ­REPORT (position ­report)

    N/A

    N

    RTED-5

    Position report.

    POSITION RE­PORT (position re­port)

    DM51 WHEN ­CAN WE EXPECT ­BACK ON ­ROUTE

    N/A

    Y

    RTED-8

    Request for the ­specified heading.

    WHEN CAN WE ­EXPECT BACK ­ON ROUTE

    DM70 REQUEST ­HEADING (de­grees)

    N/A

    Y

    RTED-6

    Request for the ­specified heading.

    REQUEST HEAD­ING (degrees)

    DM71 REQUEST ­GROUND TRACK ­(degrees)

    N/A

    Y

    RTED-7

    Request for the ­specified ground ­track.

    REQUEST ­GROUND TRACK ­(degrees)

    TBL ENR 7.2-4Lateral Uplink Message Elements (LATU)

    CPDLC Message Sets

    Operational Definition in PANS-ATM (Doc 4444)

    FANS 1/A

    ATN B1

    Response

    Message ­Element ­Identifier

    Message Element ­Intended Use

    Format for Mes­sage Element Dis­play

    UM64 OFFSET ­(distance offset) ­(direction) OF ­ROUTE

    UM64 OFFSET ­(specified distance) ­(direction) OF ­ROUTE

    W/U

    LATU-1

    Instruction to fly a ­parallel track to the ­cleared route at a ­displacement of the ­specified distance ­in the specified di­rection.

    OFFSET (specified ­distance) (direc­tion) OF ROUTE

    UM65 AT (posi­tion) OFFSET (dis­tance offset) (direc­tion) OF ROUTE

    N/A

    W/U

    LATU-2

    Instruction to fly a ­parallel track to the ­cleared route at a ­displacement of the ­specified distance ­in the specified di­rection and com­mencing at the ­specified position.

    AT (position) OFF­SET (specified dis­tance) (direction) ­OF ROUTE

    UM66 AT (time) ­OFFSET (distance ­offset) (direction) ­OF ROUTE

    N/A

    W/U

    LATU-3

    Instruction to fly a ­parallel track to the ­cleared route at a ­displacement of the ­specified distance ­in the specified di­rection and com­mencing at the ­specified time.

    AT TIME (time) ­OFFSET (specified ­distance) (direc­tion) OF ROUTE

    UM67 PROCEED ­BACK ON ­ROUTE

    N/A

    W/U

    LATU-4

    Instruction to rejoin ­thecleared route.

    REJOIN ROUTE

    UM68 REJOIN ­ROUTE BY (posi­tion)

    N/A

    W/U

    LATU-5

    Instruction to rejoin ­thecleared route be­fore passing the ­specified position.

    REJOIN ROUTE ­BEFORE PASS­ING (position)

    UM69 REJOIN ­ROUTE BY (time)

    N/A

    W/U

    LATU-6

    Instruction to rejoin ­the cleared route ­before the specified ­time.

    REJOIN ROUTE ­BEFORE TIME ­(time)

    UM70 EXPECT ­BACK ON ­ROUTE BY (posi­tion)

    N/A

    R

    LATU-7

    Notification that a ­clearance may be ­issued to enable the ­aircraft to rejoin ­the cleared route ­before passing the ­specified position.

    EXPECT BACK ­ON ROUTE BE­FORE PASSING ­(position)

    UM71 EXPECT ­BACK ON ­ROUTE BY (time)

    N/A

    R

    LATU-8

    Notification that a ­clearance may be ­issued to enable the ­aircraft to rejoin ­the cleared route ­before the specified ­time.

    EXPECT BACK ­ON ROUTE BE­FORE TIME (time)

    UM72 RESUME ­OWN NAVIGA­TION

    UM72 RESUME ­OWN NAVIGA­TION

    W/U

    LATU-9

    Instruction to re­sume own naviga­tion following a pe­riod of tracking or ­heading clearances. ­May be used in ­conjunction with an ­instruction on how ­or where to rejoin ­the cleared route.

    RESUME OWN ­NAVIGATION

    UM82 CLEARED ­TO DEVIATE UP ­TO (distance off­set) (direction) OF ­ROUTE

    UM82 CLEARED ­TO DEVIATE UP ­TO (specified dis­tance) (direction) ­OF ROUTE

    W/U

    LATU-10

    Instruction allow­ing deviation up to ­the specified dis­tance(s) from the ­cleared route in the ­specified direc­tion(s).

    CLEARED TO ­DEVIATE UP TO ­(lateral deviation) ­OF ROUTE

    UM98 IMMEDI­ATELY TURN (di­rection) HEAD­ING (degrees)Note – This mes­sage element is ­equivalent to ­EMGU-2 plus ­LATU-11 in Doc ­4444.

    N/A

    W/U

    LATU-11

    Instruction to turn ­left or right as ­specified on to the ­specified heading.

    TURN (direction) ­HEADING (de­grees)

    UM127 REPORT ­BACK ON ­ROUTENote – R response ­attribute.

    N/A

    W/U

    LATU-18

    Instruction to re­port when the air­craft is back on the ­cleared route.

    REPORT BACK ­ON ROUTE

    UM130 REPORT ­PASSING (posi­tion)Note– R response ­attribute.

    N/A

    W/U

    LATU-19

    Instruction to re­port upon passing ­the specified posi­tion.

    REPORT PASS­ING (position)

    UM132 CONFIRM ­POSITION

    N/A

    NE

    N/A

    Instruction to re­port the present po­sition.

    N/A

    UM138 CONFIRM ­TIME OVER RE­PORTED WAY­POINT

    N/A

    NE

    N/A

    Instruction to con­firm the previously ­reported time over ­the last reported ­waypoint.

    N/A

    UM139 CONFIRM ­REPORTED ­WAYPOINT

    N/A

    NE

    N/A

    Instruction to con­firm the identity of ­the previously re­ported waypoint.

    N/A

    UM140 CONFIRM ­NEXT WAY­POINT

    N/A

    NE

    N/A

    Instruction to con­firm the identity of ­the next waypoint.

    N/A

    UM141 CONFIRM ­NEXT WAY­POINT ETA

    N/A

    NE

    N/A

    Instruction to con­firm the previously ­reported estimated ­time at the next ­waypoint.

    N/A

    UM142 CONFIRM ­ENSUING WAY­POINT

    N/A

    NE

    N/A

    Instruction to con­firm the identity of ­the next plus one ­waypoint.

    N/A

    UM145 CONFIRM ­HEADING

    N/A

    NE

    N/A

    Instruction to re­port the present ­heading.

    N/A

    UM146 REPORT ­GROUND TRACK

    N/A

    NE

    N/A

    Instruction to re­port the present ­ground track.

    N/A

    UM152 WHEN ­CAN YOU AC­CEPT (specified ­distance) (direc­tion) OFFSET

    N/A

    NE

    N/A

    Instruction to re­port the earliest ­time when the ­specified offset ­track can be ac­cepted.

    N/A

    TBL ENR 7.2-5Lateral Downlink Message Elements (LATD)

    CPDLC Message Sets

    Operational Definition in PANS-ATM (Doc 4444)

    FANS 1/A

    ATN B1

    Response

    Message ­Element ­Identifier

    Message Element ­Intended Use

    Format for Mes­sage Element Dis­play

    DM15 REQUEST ­OFFSET (specified ­distance) (direc­tion) OF ROUTE

    N/A

    Y

    LATD-1

    Request for a paral­lel track from the ­cleared route at a ­displacement of the ­specified distance ­in the specified di­rection.

    REQUEST OFF­SET (specified dis­tance) (direction) ­OF ROUTE

    DM16 AT (posi­tion) REQUEST ­OFFSET (specified ­distance) (direc­tion) OF ROUTE

    N/A

    Y

    N/A

    Request that a par­allel track, offset ­from the cleared ­track by the speci­fied distance in the ­specified direction, ­be approved from ­the specified posi­tion.

    N/A

    DM17 AT (time) ­REQUEST OFF­SET (specified dis­tance) (direction) ­OF ROUTE

    N/A

    Y

    N/A

    Request that a par­allel track, offset ­from the cleared ­track by the speci­fied distance in the ­specified direction, ­be approved from ­the specified time.

    N/A

    DM27 REQUEST ­WEATHER DEVI­ATION UP TO ­(specified distance) ­(direction) OF ­ROUTE

    DM27 REQUEST ­WEATHER DEVI­ATION UP TO ­(specified distance) ­(direction) OF ­ROUTE

    Y

    LATD-2

    Request for a ­weather deviation ­up to the specified ­distance(s) off ­track in the speci­fied direction(s).

    REQUEST ­WEATHER DEVI­ATION UP TO ­(lateral deviation) ­OF ROUTE

    DM31 PASSING ­(position)

    N/A

    N

    LATD-8

    Report indicating ­passing the speci­fied position.

    PASSING (posi­tion)

    DM33 PRESENT ­POSITION (posi­tion)

    N/A

    N

    N/A

    Notification of the ­present position.

    N/A

    DM35 PRESENT ­HEADING (de­grees)

    N/A

    N

    N/A

    Notification of the ­present heading in ­degrees.

    N/A

    DM36 PRESENT ­GROUND TRACK ­(degrees)

    N/A

    N

    N/A

    Notification of the ­present ground ­track in degrees.

    N/A

    DM41 BACK ON ­ROUTE

    N/A

    N

    LATD-4

    Report indicating ­that the cleared ­route has been re­joined.

    BACK ON ­ROUTE

    DM42 NEXT ­WAYPOINT (posi­tion)

    N/A

    N

    N/A

    The next waypoint ­is the specified po­sition.

    N/A

    DM43 NEXT ­WAYPOINT ETA ­(time)

    N/A

    N

    N/A

    The ETA at the ­next waypoint is as ­specified.

    N/A

    DM44 ENSUING ­WAYPOINT (posi­tion)

    N/A

    N

    N/A

    The next plus one ­waypoint is the ­specified position.

    N/A

    DM45 REPORT­ED WAYPOINT ­(position)

    N/A

    N

    N/A

    Clarification of ­previously reported ­waypoint passage.

    N/A

    DM46 REPORT­ED WAYPOINT ­(time)

    N/A

    N

    N/A

    Clarification of ­time over previous­ly reported way­point.

    N/A

    DM59 DIVERT­ING TO (position) ­VIA (route clear­ance)Note 1 – H alert at­tribute.Note 2 – N re­sponse attribute.

    N/A

    Y

    LATD-5

    Report indicating ­diverting to the ­specified position ­via the specified ­route, which may ­be sent without any ­previous coordina­tion done with ­ATC.

    DIVERTING TO ­(position) VIA (en-­route data) (arrival ­approach data[O])

    DM60 OFFSET­TING (distance off­set) (direction) OF ­ROUTENote 1 – H alert at­tribute.Note 2 – N re­sponse attribute.

    N/A

    Y

    LATD-6

    Report indicating ­that the aircraft is ­offsetting to a par­allel track at the ­specified distance ­in the specified di­rection off from the ­cleared route.

    OFFSETTING ­(specified distance) ­(direction) OF ­ROUTE

    DM80 DEVIAT­ING (deviation Off­set) (direction) OF ­ROUTENote 1 – H alert at­tribute.Note 2 – N re­sponse attribute

    N/A

    Y

    LATD-7

    Report indicating ­deviating specified ­distance or degrees ­in the specified di­rection from the ­cleared route.

    DEVIATING ­(specified Devia­tion) (direction) OF ­ROUTE

    DM67 WE CAN ­ACCEPT (direc­tion) (distance off­set) AT (time)

    N/A

    N

    N/A

    We can accept a ­parallel track offset ­the specified dis­tance in the speci­fied direction at the ­specified time.

    N/A

    DM67 WE CAN­NOT ACCEPT (di­rection) (distance ­offset)

    N/A

    N

    N/A

    We cannot accept a ­parallel track offset ­the specified dis­tance in the speci­fied direction.

    N/A

    DM67 WE CAN­NOT ACCEPT (al­titude)

    N/A

    N

    N/A

    We cannot accept ­the specified alti­tude.

    N/A

    TBL ENR 7.2-6Level Uplink Message Elements (LVLU)

    CPDLC Message Sets

    Operational Definition in PANS-ATM (Doc 4444)

    FANS 1/A

    ATN B1

    Response

    Message Ele­ment Identifier

    Message Ele­ment Intended ­Use

    Format for ­Message Ele­ment Display

    UM6 EXPECT ­(altitude)

    N/A

    R

    N/A

    Notification that ­a level change ­instruction ­should be ex­pected.

    N/A

    UM7 EXPECT ­CLIMB AT ­(time)

    N/A

    R

    LVLU-1

    Notification that ­an instruction ­may be expect­ed for the air­craft to com­mence climb at ­the specified ­time.

    EXPECT ­HIGHER AT ­TIME (time)

    UM8 EXPECT ­CLIMB AT (po­sition)

    N/A

    R

    LVLU-2

    Notification that ­an instruction ­may be expect­ed for the air­craft to com­mence climb at ­the specified po­sition.

    EXPECT ­HIGHER AT ­(position)

    UM9 EXPECT ­DESCENT AT ­(time)

    N/A

    R

    LVLU-3

    Notification that ­an instruction ­may be expect­ed for the air­craft to com­mence descent ­at the specified ­time.

    EXPECT LOW­ER AT TIME ­(time)

    UM10 EXPECT ­DESCENT AT ­(position)

    N/A

    R

    LVLU-4

    Notification that ­an instruction ­may be expect­ed for the air­craft to com­mence descent ­at the specified ­position.

    EXPECT LOW­ER AT (posi­tion)

    UM11 EXPECT ­CRUISE ­CLIMB AT ­(time)

    N/A

    R

    N/A

    Notification that ­an instruction ­should be ex­pected for the ­aircraft to com­mence cruise ­climb at the ­specified time.Due to different ­interpretations ­between the var­ious ATS units ­this, element ­should be avoid­ed.

    N/A

    UM12 EXPECT ­CRUISE ­CLIMB AT (po­sition)

    N/A

    R

    N/A

    Notification that ­an instruction ­should be ex­pected for the ­aircraft to com­mence cruise ­climb at the ­specified posi­tion.Due to different ­interpretations ­between the var­ious ATS units, ­this element ­should be avoid­ed.

    N/A

    UM13 AT ­(time) EXPECT ­CLIMB TO (al­titude)

    N/A

    R

    N/A

    Notification that ­an instruction ­should be ex­pected for the ­aircraft to com­mence climb at ­the specified ­time to the spec­ified level.

    N/A

    UM14 AT (po­sition) EXPECT ­CLIMB TO (al­titude)

    N/A

    R

    N/A

    Notification that ­an instruction ­should be ex­pected for the ­aircraft to com­mence climb at ­the specified po­sition to the ­specified level.

    N/A

    UM15 AT ­(time) EXPECT ­DESCENT TO ­(altitude)

    N/A

    R

    N/A

    Notification that ­an instruction ­should be ex­pected for the ­aircraft to com­mence descent ­at the specified ­time to the spec­ified level.

    N/A

    UM16 AT (po­sition) EXPECT ­DESCENT TO ­(altitude)

    N/A

    R

    N/A

    Notification that ­an instruction ­should be ex­pected for the ­aircraft to com­mence descent ­at the specified ­position to the ­specified level.

    N/A

    UM17 AT ­(time) EXPECT ­CRUISE ­CLIMB TO (al­titude)

    N/A

    R

    N/A

    Notification that ­an instruction ­should be ex­pected for the ­aircraft to com­mence cruise ­climb at the ­specified time to ­the specified ­level.Due to different ­interpretations ­between the var­ious ATS units, ­this element ­should be avoid­ed.

    N/A

    UM18 AT (po­sition) EXPECT ­CRUISE ­CLIMB TO (al­titude)

    N/A

    R

    N/A

    Notification that ­an instruction ­should be ex­pected for the ­aircraft to com­mence cruise ­climb at the ­specified posi­tion to the speci­fied level.Due to different ­interpretations ­between the var­ious ATS units, ­this element ­should be avoid­ed.

    N/A

    UM19 MAIN­TAIN (altitude)Note – Used for ­a single level.

    UM19 MAIN­TAIN (level)

    W/U

    LVLU-5

    Instruction to ­maintain the ­specified level ­or vertical ­range.

    MAINTAIN ­(level)

    UM20 CLIMB ­TO AND ­MAINTAIN ­(altitude)Note – Used for ­a single level.

    UM20 CLIMB ­TO (level)

    W/U

    LVLU-6

    Instruction that ­a climb to the ­specified level ­or vertical range ­is to commence ­and once ­reached is to be ­maintained.

    CLIMB TO ­(level)

    UM21 AT ­(time) CLIMB ­TO AND ­MAINTAIN ­(altitude)Note – A verti­cal range can ­not be provided.

    N/A

    W/U

    LVLU-7

    Instruction that ­at the specified ­time a climb to ­the specified ­level or vertical ­range is to com­mence and once ­reached is to be ­maintained.Note – This ­message ele­ment would be ­preceded with ­LVLU-5 MAIN­TAIN (level) to ­prevent the pre­mature execu­tion of the in­struction.

    AT TIME (time) ­CLIMB TO ­(level)

    UM22 AT (po­sition) CLIMB ­TO AND ­MAINTAIN ­(altitude)Note – A verti­cal range can ­not be provided.

    N/A

    W/U

    LVLU-8

    Instruction that ­at the specified ­position a climb ­to the specified ­level or vertical ­range is to com­mence and once ­reached is to be ­maintained.Note – This ­message ele­ment would be ­preceded with ­LVLU-5 MAIN­TAIN (level) to ­prevent the pre­mature execu­tion of the in­struction.

    AT (position) ­CLIMB TO ­(level)

    UM23 DE­SCEND TO ­AND MAIN­TAIN (altitude)Note – Used for ­a single level.

    N/A

    W/U

    LVLU-9

    Instruction that ­a descent to the ­specified level ­or vertical range ­is to commence ­and once ­reached is to be ­maintained.

    DESCEND TO ­(level)

    UM24 AT ­(time) DE­SCEND TO ­AND MAIN­TAIN (altitude)Note – A verti­cal range can ­not be provided.

    N/A

    W/U

    LVLU-10

    Instruction that ­at the specified ­time a descent ­to the specified ­level or vertical ­range is to com­mence and once ­reached is to be ­maintained.

    AT TIME (time) ­DESCEND TO ­(level)

    UM25 AT (po­sition) DE­SCEND TO ­AND MAIN­TAIN (altitude)Note –A vertical ­range cannot be ­provided.

    N/A

    W/U

    LVLU-11

    Instruction that ­at the specified ­position a de­scent to the ­specified level ­or vertical range ­is to commence ­and once ­reached is to be ­maintained.

    AT (position) ­DESCEND TO ­(level)

    UM26 CLIMB ­TO REACH (al­titude) BY ­(time)

    UM26 CLIMB ­TO REACH ­(level) BY ­(time)

    W/U

    LVLU-12

    Instruction that ­a climb is to be ­completed such ­that the speci­fied level is ­reached before ­the specified ­time.

    CLIMB TO ­REACH (level ­single) BE­FORE TIME ­(time)

    UM27 CLIMB ­TO REACH (al­titude) BY (po­sition)

    UM27 CLIMB ­TO REACH ­(level) BY (po­sition)

    W/U

    LVLU-13

    Instruction that ­a climb is to be ­completed such ­that the speci­fied level is ­reached before ­passing the ­specified posi­tion.

    CLIMB TO ­REACH (level ­single) BE­FORE PASS­ING (position)

    UM28 DE­SCEND TO ­REACH (alti­tude) BY (time)

    UM28 DE­SCEND TO ­REACH (level) ­BY (time)

    W/U

    LVLU-14

    Instruction that ­a descent is to ­be completed ­such that the ­specified level ­is reached be­fore the speci­fied time.

    DESCEND TO ­REACH (level ­single) BE­FORE TIME ­(time)

    UM29 DE­SCEND TO ­REACH (alti­tude) BY (posi­tion)

    UM29 DE­SCEND TO ­REACH (level) ­BY (position)

    W/U

    LVLU-15

    Instruction that ­a descent is to ­be completed ­such that the ­specified level ­is reached be­fore passing the ­specified posi­tion.

    DESCEND TO ­REACH (level ­single) BE­FORE PASS­ING (position)

    UM30 MAIN­TAIN BLOCK ­(altitude) TO ­(altitude)Note – Used for ­a vertical range.

    UM19 MAIN­TAIN (level)

    W/U

    LVLU-5

    Instruction to ­maintain the ­specified level ­or vertical ­range.

    MAINTAIN ­(level)

    UM31 CLIMB ­TO AND ­MAINTAIN ­BLOCK (alti­tude) TO (alti­tude)Note – Used for ­a vertical range.

    UM20 CLIMB ­TO (level)

    W/U

    LVLU-6

    Instruction that ­a climb to the ­specified level ­or vertical range ­is to commence ­and once ­reached is to be ­maintained.

    CLIMB TO ­(level)

    UM32 DE­SCEND TO ­AND MAIN­TAIN BLOCK ­(altitude) TO ­(altitude)Note – Used for ­a vertical range.

    UM23 DE­SCEND TO ­(level)

    W/U

    LVLU-9

    Instruction that ­a descent to the ­specified level ­or vertical range ­is to commence ­and once ­reached is to be ­maintained.

    DESCEND TO ­(level)

    UM33 CRUISE ­(altitude)

    N/A

    W/U

    N/A

    Instruction that ­authorizes a pi­lot to conduct ­flight at any alti­tude from the ­minimum alti­tude up to and ­including the al­titude specified ­in the clearance. ­Further, it is ap­proval for the ­pilot to proceed ­to and make an ­approach at the ­destination air­port.Due to different ­interpretations ­between the var­ious ATS units, ­this element ­should be avoid­ed.

    N/A

    UM34 CRUISE ­CLIMB TO (al­titude)

    N/A

    W/U

    N/A

    A cruise climb ­is to commence ­and continue ­until the speci­fied level is ­reached.Due to different ­interpretations ­between the var­ious ATS units, ­this element ­should be avoid­ed.

    N/A

    UM35 CRUISE ­CLIMB ­ABOVE (alti­tude)

    N/A

    W/U

    N/A

    A cruise climb ­can commence ­once above the ­specified level.Due to different ­interpretations ­between the var­ious ATS units, ­this element ­should be avoid­ed.

    N/A

    UM36 EXPE­DITE CLIMB ­TO (altitude)Note – This ­message ele­ment is equiva­lent to SUPU-3 ­plus LVLU-6 in ­Doc 4444.

    N/A

    W/U

    LVLU-6

    Instruction that ­a climb to the ­specified level ­or vertical range ­is to commence ­and once ­reached is to be ­maintained.

    CLIMB TO ­(level)

    UM37 EXPE­DITE DE­SCENT TO (al­titude)Note – This ­message ele­ment is equiva­lent to SUPU-3 ­plus LVLU-9 in ­Doc 4444.

    N/A

    W/U

    LVLU-9

    Instruction that ­a descent to the ­specified level ­or vertical range ­is to commence ­and once ­reached is to be ­maintained.

    DESCEND TO ­(level)

    UM38 IMME­DIATELY ­CLIMB TO (al­titude)Used in combi­nation with ­EMGU-2 plus ­LVLU-6 in Doc ­4444 as an ur­gent instruction ­to immediately ­climb to the ­specified level.

    N/A

    W/U

    LVLU-6

    Instruction that ­a climb to the ­specified level ­or vertical range ­is to commence ­and once ­reached is to be ­maintained.

    CLIMB TO ­(level)

    UM39 IMME­DIATELY DE­SCEND TO (al­titude)Used in combi­nation with ­EMGU-2 plus ­LVLU-9 in Doc ­4444 as an ur­gent instruction ­to immediately ­descend to the ­specified level.

    N/A

    W/U

    LVLU-9

    Instruction that ­a descent to the ­specified level ­or vertical range ­is to commence ­and once ­reached is to be ­maintained.

    DESCEND TO ­(level)

    UM40 IMME­DIATELY ­STOP CLIMB ­AT (altitude)

    N/A

    W/U

    N/A

    Urgent instruc­tion to immedi­ately stop a ­climb once the ­specified level ­is reached.

    N/A

    UM41 IMME­DIATELY ­STOP DE­SCENT AT (al­titude)

    N/A

    W/U

    N/A

    Urgent instruc­tion to immedi­ately stop a de­scent once the ­specified level ­is reached.

    N/A

    UM128 RE­PORT LEAV­ING (altitude)Note – R re­sponse attribute.

    N/A

    W/U

    LVLU-23

    Instruction to ­report upon ­leaving the ­specified level.

    REPORT ­LEAVING (lev­el single)

    UM129 RE­PORT LEVEL ­(altitude)Note – R re­sponse attribute.

    N/A

    W/U

    LVLU-24

    Instruction to ­report upon ­maintaining the ­specified level.

    REPORT ­MAINTAIN­ING (level sin­gle)

    UM133 CON­FIRM ALTI­TUDE

    N/A

    NE

    N/A

    Instruction to ­report the ­present level.

    N/A

    UM135 CON­FIRM AS­SIGNED ALTI­TUDENote – NE re­sponse attribute.

    N/A

    Y

    LVLU-27

    Request to con­firm the as­signed level.

    CONFIRM AS­SIGNED LEV­EL

    UM148 WHEN ­CAN YOU AC­CEPT (altitude)Note – NE re­sponse attribute.

    UM148 WHEN ­CAN YOU AC­CEPT (level)

    Y

    LVLU-30

    Request for the ­earliest time or ­position when ­the specified ­level can be ac­cepted.

    WHEN CAN ­YOU ACCEPT ­(level single)

    UM149 CAN ­YOU ACCEPT ­(altitude) AT ­(position)

    N/A

    A/N

    LVLU-31

    Request to indi­cate whether or ­not the specified ­level can be ac­cepted at the ­specified posi­tion.

    CAN YOU AC­CEPT (level sin­gle) AT (posi­tion)

    UM150 CAN ­YOU ACCEPT ­(altitude) AT ­(time)

    N/A

    A/N

    LVLU-32

    Request to indi­cate whether or ­not the specified ­level can be ac­cepted at the ­specified time.

    CAN YOU AC­CEPT (level sin­gle) AT TIME ­(time)

    UM171 CLIMB ­AT (vertical ­rate) MINI­MUM

    UM171 CLIMB ­AT (vertical ­rate)MINIMUM

    W/U

    LVLU-18

    Instruction to ­climb at the ­specified rate or ­greater.

    CLIMB AT ­(vertical rate) ­OR GREATER

    UM172 CLIMB ­AT (vertical ­rate) MAXI­MUM

    UM172 CLIMB ­AT (vertical ­rate) MAXI­MUM

    W/U

    LVLU-19

    Instruction to ­climb at the ­specified rate or ­less.

    CLIMB AT ­(vertical rate) ­OR LESS

    UM173 DE­SCEND AT ­(vertical rate) ­MINIMUM

    UM173 DE­SCEND AT ­(vertical rate) ­MINIMUM

    W/U

    LVLU-20

    Instruction to ­descend at the ­specified rate or ­greater.

    DESCEND AT ­(vertical rate) ­OR GREATER

    UM174 DE­SCEND AT ­(vertical rate) ­MAXIMUM

    UM174 DE­SCEND AT ­(vertical rate) ­MAXIMUM

    W/U

    LVLU-21

    Instruction to ­descend at the ­specified rate or ­less.

    DESCEND AT ­(vertical rate) ­OR LESS

    UM175 RE­PORT REACH­ING (altitude)

    N/A

    R

    N/A

    Instruction to ­report when the ­aircraft has ­reached the ­specified alti­tude.

    N/A

    UM177 AT PI­LOTS DISCRE­TION

    N/A

    N

    N/A

    Note – To be in­terpreted as ­“Report reach­ing an assigned ­altitude.”

    N/A

    UM180 ­REACHING ­BLOCK (alti­tude) TO (alti­tude)Note – R re­sponse attribute.

    N/A

    W/U

    LVLU-26

    Instruction to ­report upon ­reaching the ­specified verti­cal range.

    REPORT ­REACHING ­BLOCK (level ­single) TO (lev­el single)

    TBL ENR 7.2-7Level Downlink Message Elements (LVLD)

    CPDLC Message Sets

    Operational Definition in PANS-ATM (Doc 4444)

    FANS 1/A

    ATN B1

    Response

    Message ­Element ­Identifier

    Message Element ­Intended Use

    Format for Mes­sage Element Dis­play

    DM6 REQUEST ­(altitude)Note –Used for a ­single level.

    DM6 REQUEST ­(level)

    Y

    LVLD-1

    Request to fly at ­the specified level ­or vertical range.

    REQUEST (level)

    DM7 REQUEST ­BLOCK (altitude) ­TO (altitude)Note – Used for a ­vertical range.

    DM6 REQUEST ­(level)

    Y

    LVLD-1

    Request to fly at ­the specified level ­or vertical range.

    REQUEST (level)

    DM8 REQUEST ­CRUISE CLIMB ­TO (altitude)

    N/A

    Y

    N/A

    Request to cruise ­climb to the speci­fied level.Due to different in­terpretations be­tween the various ­ATS units, this ele­ment should be ­avoided.

    N/A

    DM9 REQUEST ­CLIMB TO (alti­tude)Note – Use of DM7 ­REQUEST BLOCK ­(altitude) TO (alti­tude) to request to ­climb at a vertical ­range.

    DM9 REQUEST ­CLIMB TO (level)

    Y

    LVLD-2

    Request for a climb ­to the specified lev­el or vertical range.

    REQUEST CLIMB ­TO (level)

    DM10 REQUEST ­DESCENT TO (al­titude)Note – Use of DM7 ­REQUEST BLOCK ­(altitude) TO (alti­tude) to request to ­descend at a verti­cal range.

    DM10 REQUEST ­DESCENT TO ­(level)

    Y

    LVLD-3

    Request for a de­scent to the speci­fied level or verti­cal range.

    REQUEST CLIMB ­TO (level)

    DM11 AT (posi­tion) REQUEST ­CLIMB TO (alti­tude)Note – A vertical ­range cannot be re­quested.

    N/A

    Y

    LVLD-4

    Request for a ­climb/descent to ­the specified level ­or vertical range to ­commence at the ­specified position.

    AT (position) RE­QUEST (level)

    DM12 AT (posi­tion) REQUEST ­DESCENT TO (al­titude)Note – A vertical ­range cannot be re­quested.

    N/A

    Y

    LVLD-4

    Request for a ­climb/descent to ­the specified level ­or vertical range to ­commence at the ­specified position.

    AT (position) RE­QUEST (level)

    DM13 AT TIME ­(time) REQUEST ­CLIMB TO (alti­tude)Note – A vertical ­range cannot be re­quested.

    N/A

    Y

    LVLD-5

    Request for a ­climb/descent to ­the specified level ­or vertical range to ­commence at the ­specified time.

    AT TIME (time) ­REQUEST (level)

    DM14 AT TIME ­(time) REQUEST ­DESCENT TO (al­titude)Note – A vertical ­range cannot be re­quested.

    N/A

    Y

    LVLD-5

    Request for a ­climb/descent to ­the specified level ­or vertical range to ­commence at the ­specified time.

    AT TIME (time) ­REQUEST (level)

    DM28 LEAVING ­(altitude)

    N/A

    N

    LVLD-8

    Report indicating ­leaving the speci­fied level

    LEAVING (level ­single)

    DM29 CLIMBING ­TO (altitude)

    N/A

    N

    LVLD-13

    Report indicating ­climbing to the ­specified level.

    CLIMBING TO ­(level single)

    DM30 DESCEND­ING TO (altitude)Note – N alert at­tribute.

    N/A

    N

    LVLD-14

    Report indicating ­descending to the ­specified level.

    DESCENDING ­TO (level single)

    DM32 PRESENT ­ALTITUDE (alti­tude)

    DM32 PRESENT ­LEVEL (altitude)

    N

    LVLD-19

    Notification of the ­present level.

    Present level (sin­gle level)

    DM37 LEVEL (al­titude)

    N/A

    N

    LVLD-9

    Report indicating ­that the specified ­level is being main­tained.

    MAINTAINING ­(level single)

    DM38 ASSIGNED ­ALTITUDE (alti­tude)Note – Used for a ­single level

    DM38 ASSIGNED ­LEVEL (level)

    N

    LVLD-11

    Confirmation that ­the assigned level ­or vertical range is ­the specified level ­or vertical range.

    ASSIGNED LEV­EL (level)

    DM52 WHEN ­CAN WE EXPECT ­LOWER ALTI­TUDE

    N/A

    Y

    LVLD-6

    Request for the ear­liest time or posi­tion that a descent ­can be expected.

    WHEN CAN WE ­EXPECT LOWER ­LEVEL

    DM53 WHEN ­CAN WE EXPECT ­HIGHER ALTI­TUDE

    N/A

    Y

    LVLD-7

    Request for the ear­liest time or posi­tion that a climb ­can be expected.

    WHEN CAN WE ­EXPECT HIGHER ­LEVEL

    DM54 WHEN ­CAN WE EXPECT ­CRUISE CLIMB ­TO (altitude)

    N/A

    Y

    N/A

    Request for the ear­liest time at which ­a clearance to ­cruise climb to the ­specified level can ­be expected.

    N/A

    DM61 DESCEND­ING TO (altitude)Note – Urgent ­alert attribute.

    N/A

    N

    LVLD-14

    Report indicating ­descending to the ­specified level.

    DESCENDING ­TO (level single)

    DM67 WE CAN ­ACCEPT (altitude) ­AT TIME (time)

    DM81 WE CAN ­ACCEPT (level) ­AT (time)Note – A vertical ­range may be pro­vided.

    N

    LVLD-15

    Indication that the ­specified level can ­be accepted at the ­specified time.

    WE CAN AC­CEPT (level single) ­AT TIME (time)

    DM67 WE CAN­NOT ACCEPT (al­titude)

    DM82 WE CAN­NOT ACCEPT ­(level)Note – A vertical ­range may be pro­vided.

    N

    LVLD-17

    Indication that the ­specified level can­not be accepted.

    WE CANNOT AC­CEPT (level single)

    DM67 WHEN ­CAN WE EXPECT ­CLIMB TO (alti­tude)

    N/A

    N

    N/A

    Request for the ear­liest time at which ­a clearance to ­climb to the speci­fied level can be ­expected.

    N/A

    DM 67 WHEN ­CAN WE EXPECT ­DESCENT TO (al­titude)

    N/A

    N

    N/A

    Request for the ear­liest time at which ­a clearance to de­scend to the speci­fied level can be ­expected.

    N/A

    DM72 REACH­ING (altitude)

    N/A

    N

    N/A

    Notification that ­the aircraft has ­reached the speci­fied level.

    N/A

    DM75 AT PILOTS ­DISCRETION

    N/A

    N

    N/A

    Used in conjunc­tion with another ­message to indicate ­that the pilot wish­es to execute the ­request when the ­pilot is prepared to ­do so.

    N/A

    DM76 REACH­ING BLOCK (alti­tude) TO (altitude)

    N/A

    N

    LVLD-10

    Report indicating ­reaching the speci­fied vertical range.

    REACHING ­BLOCK (level sin­gle) TO (level sin­gle)

    DM77 ASSIGNED ­BLOCK (altitude) ­TO (altitude)Note – Used for a ­vertical range.

    DM38 ASSIGNED ­LEVEL (level)

    N

    LVLD-11

    Confirmation that ­the assigned level ­or vertical range is ­the specified level ­or vertical range.

    ASSIGNED LEV­EL (level)

    TBL ENR 7.2-8Crossing Constraints Uplink Message Elements (CSTU)

    CPDLC Message Sets

    Operational Definition in PANS-ATM (Doc 4444)

    FANS 1/A

    ATN B1

    Response

    Message ­Element ­Identifier

    Message Element ­Intended Use

    Format for Mes­sage Element Dis­play

    UM42 EXPECT ­TO CROSS (posi­tion) AT (altitude)

    N/A

    R

    N/A

    Notification that a ­level change in­struction should be ­expected which ­will require the ­specified position ­to be crossed at the ­specified level.

    N/A

    UM43 EXPECT ­TO CROSS (posi­tion) AT OR ­ABOVE (altitude)

    N/A

    R

    N/A

    Notification that a ­level change in­struction should be ­expected which ­will require the ­specified position ­to be crossed at or ­above the specified ­level.

    N/A

    UM44 EXPECT ­TO CROSS (posi­tion) AT OR BE­LOW (altitude)

    N/A

    R

    N/A

    Notification that a ­level change in­struction should be ­expected which ­will require the ­specified position ­to be crossed at or ­below the specified ­level.

    N/A

    UM45 EXPECT ­TO CROSS (posi­tion) AT AND ­MAINTAIN (alti­tude)

    N/A

    R

    N/A

    Notification that a ­level change in­struction should be ­expected which ­will require the ­specified position ­to be crossed at the ­specified level ­which is to be ­maintained subse­quently.

    N/A

    UM46 CROSS (po­sition) AT (alti­tude)Note – Used for a ­single level.

    UM46 CROSS (po­sition) AT (level)

    W/U

    CSTU-1

    Instruction that the ­specified position ­is to be crossed at ­the specified level ­or within the speci­fied vertical range.

    CROSS (position) ­AT (level)

    UM47 CROSS (po­sition) AT OR ­ABOVE (altitude)

    UM47 CROSS (po­sition) AT OR ­ABOVE (level)

    W/U

    CSTU-2

    Instruction that the ­specified position ­is to be crossed at ­or above the speci­fied level.

    CROSS (position) ­AT OR ABOVE ­(level single)

    UM48 CROSS (po­sition) AT OR BE­LOW (altitude)

    UM48 CROSS (po­sition) AT OR BE­LOW (altitude)

    W/U

    CSTU-3

    Instruction that the ­specified position ­is to be crossed at ­or below the speci­fied level.

    CROSS (position) ­AT OR BELOW ­(level single)

    UM49 CROSS (po­sition) AT AND ­MAINTAIN (alti­tude)Note 1. – A vertical ­range cannot be ­provided.Note 2. – This mes­sage element is ­equivalent to ­CSTU-1 plus ­LVLU-5 in Doc ­4444.

    N/A

    W/U

    CSTU-1

    Instruction that the ­specified position ­is to be crossed at ­the specified level ­or within the speci­fied vertical range.

    CROSS (position) ­AT (level)

    UM50 CROSS (po­sition) BETWEEN ­(altitude) AND (al­titude)Note – Used for a ­vertical range.

    UM46 CROSS (po­sition) AT (level)

    W/U

    CSTU-1

    Instruction that the ­specified position ­is to be crossed at ­the specified level ­or within the speci­fied vertical range.

    CROSS (position) ­AT (level)

    UM51 CROSS (po­sition) AT (time)

    UM51 CROSS (po­sition) AT (time)

    W/U

    CSTU-4

    Instruction that the ­specified position ­is to be crossed at ­the specified time.

    CROSS (position) ­AT TIME(time)

    UM52 CROSS (po­sition) AT OR BE­FORE (time)

    UM52 CROSS (po­sition) AT OR BE­FORE (time)

    W/U

    CSTU-5

    Instruction that the ­specified position ­is to be crossed be­fore the specified ­time.

    CROSS (position) ­BEFORE TIME ­(time)

    UM53 CROSS (po­sition) AT OR AF­TER (time)

    UM53 CROSS (po­sition) AT OR AF­TER (time)

    W/U

    CSTU-6

    Instruction that the ­specified position ­is to be crossed af­ter the specified ­time.

    CROSS (position) ­AFTER TIME ­(time)

    UM54 CROSS (po­sition) BETWEEN ­(time) AND (time)

    UM54 CROSS (po­sition) BETWEEN ­(time) AND (time)

    W/U

    CSTU-7

    Instruction that the ­specified position ­is to be crossed be­tween the specified ­times.

    CROSS (position) ­BETWEEN TIME ­(time) AND TIME ­(time)

    UM55 CROSS (po­sition) AT (speed)

    UM55 CROSS (po­sition) AT (speed)

    W/U

    CSTU-8

    Instruction that the ­specified position ­is to be crossed at ­the specified speed.

    CROSS (position) ­AT (speed)

    UM56 CROSS (po­sition) AT OR ­LESS THAN ­(speed)

    N/A

    W/U

    CSTU-9

    Instruction that the ­specified position ­is to be crossed at ­or less than the ­specified speed.

    CROSS (position) ­AT (speed) OR ­LESS

    UM57 CROSS (po­sition) AT OR ­GREATER THAN ­(speed)

    N/A

    W/U

    CSTU-10

    Instruction that the ­specified position ­is to be crossed at ­or greater than the ­specified speed.

    CROSS (position) ­AT (speed) OR ­GREATER

    UM58 CROSS (po­sition) AT (time) ­AT (altitude)Note – A vertical ­range cannot be ­provided.

    N/A

    W/U

    CSTU-11

    Instruction that the ­specified position ­is to be crossed at ­the specified time ­and at the level or ­within the vertical ­range as specified.

    CROSS (position) ­AT TIME(time) AT (level)

    UM59 CROSS (po­sition) AT OR BE­FORE (time) AT ­(altitude)Note – A vertical ­range cannot be ­provided.

    N/A

    W/U

    CSTU-12

    Instruction that the ­specified position ­is to be crossed be­fore the specified ­time and at the lev­el or within the ver­tical range as speci­fied.

    CROSS (position) ­BEFORE TIME ­(time) AT (level)

    UM60 CROSS (po­sition) AT OR AF­TER (time) AT (al­titude)Note – A vertical ­range cannot be ­provided.

    N/A

    W/U

    CSTU-13

    Instruction that the ­specified position ­is to be crossed af­ter the specified ­time and at the lev­el or within the ver­tical range as speci­fied.

    CROSS (position) ­AFTER TIME ­(time) AT (level)

    UM61 CROSS (po­sition) AT AND ­MAINTAIN (alti­tude) AT (speed)Note 1. – A vertical ­range cannot be ­provided.Note 2. – This mes­sage element is ­equivalent to ­CSTU-14 plus ­LVLU-5 in Doc ­4444.

    UM61 CROSS (po­sition) AT AND ­MAINTAIN (level) ­AT (speed)

    W/U

    CSTU-14

    Instruction that the ­specified position ­is to be crossed at ­the level or within ­the vertical range, ­as specified, and at ­the specified speed.

    CROSS (position) ­AT (level) AT ­(speed)

    UM62 AT (time) ­CROSS (position) ­AT AND MAIN­TAIN (altitude)

    N/A

    W/U

    NA

    Instruction that at ­the specified time ­the specified posi­tion is to be crossed ­at the specified lev­el and the level is ­to be maintained.

    N/A

    UM63 AT (time) ­CROSS (position) ­AT AND MAIN­TAIN (altitude) AT ­(speed) Note 1. – A vertical ­range cannot be ­provided.Note 2. – This mes­sage element is ­equivalent to ­CSTU-15 plus ­LVLU-5 in Doc ­4444.

    N/A

    W/U

    CSTU-15

    Instruction that the ­specified position ­is to be crossed at ­the specified time ­at the level or with­in the vertical ­range, as specified, ­and at the specified ­speed.

    CROSS (position) ­AT TIME (time) ­AT (level) AT ­(speed)

    TBL ENR 7.2-9Speed Uplink Message Elements (SPDU)

    CPDLC Message Sets

    Operational Definition in PANS-ATM (Doc 4444)

    FANS 1/A

    ATN B1

    Response

    Message ­Element ­Identifier

    Message Element ­Intended Use

    Format for Mes­sage Element Dis­play

    UM100 AT (time) ­EXPECT (speed)

    N/A

    R

    SPDU-1

    Notification that a ­speed instruction ­may be issued to ­take effect at the ­specified time.

    EXPECT SPEED ­CHANGE AT ­TIME (time)

    UM101 AT (posi­tion) EXPECT ­(speed)

    N/A

    R

    SPDU- 2

    Notification that a ­speed instruction ­may be issued to ­take effect at the ­specified position.

    EXPECT SPEED ­CHANGE AT (po­sition)

    UM102 AT (alti­tude) EXPECT ­(speed)

    N/A

    R

    SPDU-3

    Notification that a ­speed instruction ­may be issued to ­take effect at the ­specified level.

    EXPECT SPEED ­CHANGE AT (lev­el single)

    UM103 AT (time) ­EXPECT (speed) ­TO (speed)

    N/A

    R

    N/A

    Notification that a ­speed range in­struction may be is­sued to be effective ­at the specified ­time.

    N/A

    UM104 AT (posi­tion) EXPECT ­(speed) TO (speed)

    N/A

    R

    N/A

    Notification that a ­speed range in­struction may be is­sued to be effective ­at the specified po­sition.

    N/A

    UM105 AT (alti­tude) EXPECT ­(speed) TO (speed)

    N/A

    R

    N/A

    Notification that a ­speed range in­struction may be is­sued to be effective ­at the specified lev­el.

    N/A

    UM106 MAIN­TAIN (speed)

    UM106 MAIN­TAIN (speed)

    W/U

    SPDU-4

    Instruction to main­tain the specified ­speed.

    MAINTAIN ­(speed)

    UM107 MAIN­TAIN PRESENT ­SPEED

    UM107 MAIN­TAIN PRESENT ­SPEED

    W/U

    SPDU-5

    Instruction to main­tain the present ­speed.

    MAINTAIN ­PRESENT SPEED

    UM108 MAIN­TAIN (speed) ORGREATER

    UM108 MAIN­TAIN (speed) ORGREATER

    W/U

    SPDU-6

    Instruction to main­tain the specified ­speed or greater.

    MAINTAIN ­(speed) OR ­GREATER

    UM109 MAIN­TAIN (speed) OR ­LESS

    UM109 MAIN­TAIN (speed) OR ­LESS

    W/U

    SPDU-7

    Instruction to main­tain the specified ­speed or less.

    MAINTAIN ­(speed) OR LESS

    UM110 MAIN­TAIN (speed) TO ­(speed)

    N/A

    W/U

    SPDU-8

    Instruction to main­tain the specified ­speed range.

    MAINTAIN ­(speed) TO (speed)

    UM111 IN­CREASE SPEED ­TO (speed)

    N/A

    W/U

    SPDU-9

    Instruction that the ­present speed is to ­be increased to the ­specified speed and ­maintained until ­further advised.

    INCREASE ­SPEED TO (speed)

    UM112 IN­CREASE SPEED ­TO (speed) OR ­GREATER

    N/A

    W/U

    SPDU-10

    Instruction that the ­present speed is to ­be increased to the ­specified speed or ­greater, and main­tained at or above ­the specified speed ­until further ad­vised.

    INCREASE ­SPEED TO (speed) ­OR GREATER

    UM113 REDUCE ­SPEED TO (speed)

    N/A

    W/U

    SPDU-11

    Instruction that the ­present speed is to ­be reduced to the ­specified speed and ­maintained until ­further advised.

    REDUCE SPEED ­TO (speed)

    UM114 REDUCE ­SPEED TO (speed) ­OR LESS

    N/A

    W/U

    SPDU-12

    Instruction that the ­present speed is to ­be reduced to the ­specified speed or ­less, and main­tained at or below ­the specified speed ­until further ad­vised.

    REDUCE SPEED ­TO (speed) OR ­LESS

    UM115 DO NOT ­EXCEED (speed)

    N/A

    W/U

    N/A

    The specified speed ­is not to be exceed­ed.

    N/A

    UM116 RESUME ­NORMAL SPEED

    UM116 RESUME ­NORMAL SPEED

    W/U

    SPDU-13

    Instruction to re­sume a normal ­speed. The aircraft ­no longer needs to ­comply with a pre­viously issued ­speed restriction.

    RESUME NOR­MAL SPEED

    UM134 CONFIRM ­SPEEDNote – NE response ­attribute.

    N/A

    Y

    SPDU-15

    Request to report ­the speed defined ­by the speed ­type(s).

    REPORT (speed ­types) SPEED

    UM136 CONFIRM ­ASSIGNED ­SPEEDNote – NE response ­attribute.

    N/A

    Y

    SPDU-16

    Request to confirm ­the assigned speed.

    CONFIRM AS­SIGNED SPEED

    UM151 WHEN ­CAN YOU AC­CEPT (speed) Note – NE response ­attribute.

    N/A

    Y

    SPDU-17

    Request for the ear­liest time or posi­tion when the spec­ified speed can be ­accepted.

    WHEN CAN YOU ­ACCEPT (speed)

    TBL ENR 7.2-10Speed Downlink Message Elements (SPDD)

    CPDLC Message Sets

    Operational Definition in PANS-ATM (Doc 4444)

    FANS 1/A

    ATN B1

    Response

    Message ­Element ­Identifier

    Message Element ­Intended Use

    Format for Mes­sage Element Dis­play

    DM18 REQUEST ­(speed)

    DM18 REQUEST ­(speed)

    Y

    SPDD-1

    Request for the ­specified speed.

    REQUEST (speed)

    DM19 REQUEST ­(speed) TO (speed)

    N/A

    Y

    N/A

    Request to fly ­within the specified ­speed range.

    N/A

    DM34 PRESENT ­SPEED (speed)

    N/A

    N

    SPDD-3

    Report indicating ­the speed defined ­by the specified ­speed types is the ­specified speed.

    (speed types) ­SPEED (speed)

    DM39 ASSIGNED ­SPEED (speed)

    N/A

    N

    SPDD-4

    Confirmation that ­the assigned speed ­is the specified ­speed.

    ASSIGNED ­SPEED (speed)

    DM49 WHEN ­CAN WE EXPECT ­(speed)

    N/A

    Y

    SPDD-2

    Request for the ear­liest time or posi­tion that the speci­fied speed can be ­expected.

    WHEN CAN WE ­EXPECT (speed)

    DM50 WHEN ­CAN WE EXPECT ­(speed) TO (speed)

    N/A

    Y

    N/A

    Request for the ear­liest time at which ­a clearance to a ­speed within the ­specified range can ­be expected.

    N/A

    DM67 WE CAN ­ACCEPT (speed) ­AT TIME (time)

    N/A

    N

    SPDD-5

    Indication that the ­specified speed can ­be accepted at the ­specified time.

    WE CAN AC­CEPT (speed) AT ­TIME (time)

    DM67 WE CAN­NOT ACCEPT ­(speed)

    N/A

    N

    SPDD-6

    Indication that the ­specified speed ­cannot be accepted.

    WE CANNOT AC­CEPT (speed)

    TBL ENR 7.2-11Air Traffic Advisory Uplink Message Elements (ADVU)

    CPDLC Message Sets

    Operational Definition in PANS-ATM (Doc 4444)

    FANS 1/A

    ATN B1

    Response

    Message ­Element ­Identifier

    Message Element ­Intended Use

    Format for Mes­sage Element Dis­play

    UM123 SQUAWK ­(beacon code)

    UM123 SQUAWK ­(code)

    W/U

    ADVU-9

    Instruction to select ­the specified SSR ­code.

    SQUAWK (SSR ­code)

    UM124 STOP ­SQUAWK

    N/A

    W/U

    AD­VU-10

    Instruction to dis­able SSR transpon­der responses.

    STOP SQUAWK

    UM125 SQUAWK ­ALTITUDE

    N/A

    W/U

    AD­VU-12

    Instruction to in­clude level infor­mation in the SSR ­transponder re­sponses.

    SQUAWK MODE ­C

    UM126 STOP AL­TITUDE ­SQUAWK

    N/A

    W/U

    AD­VU-13

    Instruction to stop ­including level in­formation in the ­SSR transponder ­responses.

    STOP SQUAWK ­MODE C

    UM144 CONFIRM ­SQUAWKNote – NE response ­attribute.

    N/A

    Y

    AD­VU-14

    Request to confirm ­the Selected SSR ­code.

    CONFIRM ­SQUAWK CODE

    UM153 ALTIME­TER (altimeter)Note 1. – The facil­ity designation and ­the time of mea­surement cannot be ­provided.Note 2. – the FAA ­concatenates ­UM169 '(facility ­designation) AL­TIMETER (altime­ter setting)'

    UM213 (facility ­designation) AL­TIMETER (altime­ter)Note –The facility ­designation is al­ways provided and ­the time of mea­surement cannot be ­provided.

    R

    ADVU-1

    Advisory providing ­the specified al­timeter setting for ­the specified facili­ty.

    (facility designa­tion) ALTIMETER ­(altimeter setting)

    UM154 RADAR ­SERVICES TER­MINATED

    N/A

    R

    ADVU-2

    Advisory that the ­ATS surveillance ­service is terminat­ed.

    SURVEILLANCE ­SERVICE TERMI­NATED

    UM155 RADAR ­CONTACT (posi­tion)Note – The provi­sion of the position ­is required.

    N/A

    R

    ADVU-3

    Advisory that ATS ­surveillance service ­has been estab­lished. A position ­may be specified ­position.

    IDENTIFIED (po­sition[O])

    UM156 RADAR ­CONTACT LOST

    N/A

    R

    ADVU-4

    Advisory that ATS ­surveillance con­tact has been lost.

    IDENTIFICA­TION LOST

    UM158 ATIS (atis ­code)Note – The airport ­is not provided.

    N/A

    R

    ADVU-5

    ATS advisory that ­the current ATIS ­code is as speci­fied.

    ATIS (ATIS code)

    UM163 (ICAO fa­cility designation) ­(tp4Table)

    N/A

    N/E

    N/A

    Notification to the ­pilot of an ATSU ­identifier.

    N/A

    UM168 DISRE­GARD

    N/A

    N/E

    N/A

    The indicated com­munication should ­be ignored.The previously sent ­uplink CPDLC ­message shall be ­ignored. DISRE­GARD should not ­refer to a clearance ­or instruction. If ­DISREGARD is ­used, another ele­ment shall be ­added to clarify ­which message is to ­be disregarded.

    N/A

    UM179 SQUAWK ­IDENT

    UM179 SQUAWK ­IDENT

    W/U

    AD­VU-15

    Instruction that the ­‘ident’ function ­on the SSR ­transponder is to be ­actuated.

    SQUAWK IDENT

    UM182 CONFIRM ­ATIS CODE

    N/A

    N/E

    N/A

    Instruction to re­port the identifica­tion code of the last ­ATIS received.

    N/A

    TBL ENR 7.2-12Air Traffic Advisory Downlink Message Elements (ADVD)

    CPDLC Message Sets

    Operational Definition in PANS-ATM (Doc 4444)

    FANS 1/A

    ATN B1

    Response

    Message ­Element ­Identifier

    Message Element ­Intended Use

    Format for Mes­sage Element Dis­play

    DM47 SQUAWK­ING (code)

    N/A

    N

    ADVD-1

    Report indicating ­that the aircraft is ­squawking the ­specified SSR ­code.

    SQUAWKING ­(SSR code)

    DM79 ATIS (ATIS ­code)

    N/A

    N

    N/A

    The code of the lat­est ATIS received ­is as specified.

    N/A

    TBL ENR 7.2-13Voice Communications Uplink Message Elements (COMU)

    CPDLC Message Sets

    Operational Definition in PANS-ATM (Doc 4444)

    FANS 1/A

    ATN B1

    Response

    Message ­Element ­Identifier

    Message Element ­Intended Use

    Format for Mes­sage Element Dis­play

    UM117 CON­TACT (ICAO unit ­name) (frequency)

    UM117 CON­TACT (ICAO unit ­name) (frequency)

    W/U

    COMU-1

    Instruction to es­tablish voice con­tact with the speci­fied ATS unit on ­the specified fre­quency.

    CONTACT (unit ­name) (frequency)

    UM118 AT (posi­tion) CONTACT ­(ICAO unit name) ­(frequency)

    N/A

    W/U

    COMU-2

    Instruction at the ­specified position ­to establish voice ­contact with the ­specified ATS unit ­on the specified ­frequency.

    AT (position) ­CONTACT (unit ­name) (frequency)

    UM119 AT (time) ­CONTACT (ICAO ­unit name) (fre­quency)

    N/A

    W/U

    COMU-3

    Instruction at the ­specified time to ­establish voice con­tact with the speci­fied ATS unit on ­the specified fre­quency.

    AT TIME (time) ­CONTACT (unit ­name) (frequency)

    UM120 MONI­TOR (ICAO unit ­name) (frequency)

    UM120 MONI­TOR (ICAO unit ­name) (frequency)

    W/U

    COMU-5

    Instruction to mon­itor the specified ­ATS unit on the ­specified frequen­cy. The flight crew ­is not required to ­establish voice con­tact on the frequen­cy.

    MONITOR (unit ­name) (frequency)

    UM121 AT (posi­tion) MONITOR ­(ICAO unit name) ­(frequency)

    N/A

    W/U

    COMU-6

    Instruction at the ­specified position ­to monitor the ­specified ATS unit ­on the specified ­frequency. The ­flight crew is not ­required to estab­lish voice contact ­on the frequency.

    AT (position) ­MONITOR (unit ­name) (frequency)

    UM122 AT (time) ­MONITOR (ICAO ­unit name) (fre­quency)

    N/A

    W/U

    COMU-7

    Instruction at the ­specified time to ­monitor the speci­fied ATS unit on ­the specified fre­quency. The flight ­crew is not re­quired to establish ­voice contact on ­the frequency.

    AT TIME (time) ­MONITOR (unit ­name) (frequency)

    UM157 CHECK ­STUCK MICRO­PHONE (frequen­cy)Note – R response ­attribute.

    UM157 CHECK ­STUCK MICRO­PHONE (frequen­cy)

    N

    COMU-8

    Instruction to check ­the microphone due ­to detection of a ­continuous trans­mission on the ­specified frequen­cy.

    CHECK STUCK ­MICROPHONE ­(frequency)

    TBL ENR 7.2-14Voice Communications Downlink Message Elements (COMD)

    CPDLC Message Sets

    Operational Definition in PANS-ATM (Doc 4444)

    FANS 1/A

    ATN B1

    Response

    Message ­Element ­Identifier

    Message Element ­Intended Use

    Format for Mes­sage Element Dis­play

    DM20 REQUEST ­VOICE CON­TACT Note – Used when ­a frequency is not ­required.

    N/A

    Y

    COMD-1

    Request for voice ­contact on the ­specified frequen­cy.

    REQUEST VOICE ­CONTACT (fre­quency)

    DM21 REQUEST ­VOICE CON­TACT (frequency)Note – Used when ­a frequency is re­quired.

    N/A

    Y

    COMD-1

    Request for voice ­contact on the ­specified frequen­cy.

    REQUEST VOICE ­CONTACT (fre­quency)

    TBL ENR 7.2-15Emergency/Urgency Uplink Message Elements (EMGU)

    CPDLC Message Sets

    Operational Definition in PANS-ATM (Doc 4444)

    FANS 1/A

    ATN B1

    Response

    Message ­Element ­Identifier

    Message Element ­Intended Use

    Format for Mes­sage Element Dis­play

    UM131 REPORT ­REMAINING FU­EL AND SOULS ­ON BOARDNote – NE response ­attribute.

    N/A

    Y

    EMGU-1

    Request to provide ­the fuel Remaining ­(time) and the ­number of persons ­on board.

    REPORT EN­DURANCE AND ­PERSONS ON ­BOARD

    TBL ENR 7.2-16Emergency/Urgency Downlink Message Elements (EMGD)

    CPDLC Message Sets

    Operational Definition in PANS-ATM (Doc 4444)

    FANS 1/A

    ATN B1

    Response

    Message ­Element ­Identifier

    Message Element ­Intended Use

    Format for Mes­sage Element Dis­play

    DM55 PAN PAN ­PANNote – N response ­attribute.

    N/A

    Y

    EMGD-1

    Indication of an ur­gent situation.

    PAN PAN PAN

    DM56 MAYDAY ­MAYDAY MAY­DAYNote – N response ­attribute.

    N/A

    Y

    EMGD-2

    Indication of an ­emergency situa­tion.

    MAYDAY MAY­DAY MAYDAY

    DM57 (remaining ­fuel) OF FUEL ­REMAINING ­AND (remaining ­souls) SOULS ON ­BOARDNote – N response ­attribute.

    N/A

    Y

    EMGD-3

    Report indicating ­fuel Remaining ­(time) and number ­of persons on ­board.

    (remaining fuel) ­ENDURANCE ­AND (persons on ­board) PERSONS ­ON BOARD

    DM58 CANCEL ­EMERGENCYNote – N response ­attribute.

    N/A

    Y

    EMGD-4

    Indication that the ­emergency situa­tion is cancelled.

    CANCEL EMER­GENCY

    TBL ENR 7.2-17Standard Response Uplink Message Elements (RSPU)

    CPDLC Message Sets

    Operational Definition in PANS-ATM (Doc 4444)

    FANS 1/A

    ATN B1

    Response

    Message ­Element ­Identifier

    Message Element ­Intended Use

    Format for Mes­sage Element Dis­play

    UM0 UNABLE

    UM0 UNABLE

    N

    RSPU-1

    Indication that the ­message cannot be ­complied with.

    UNABLE

    UM1 STANDBY

    UM1 STANDBY

    N

    RSPU-2

    Indication that the ­message will be re­sponded to shortly.

    STANDBY

    UM2 REQUEST ­DEFERRED

    N/A

    N

    RSPU-3

    Indication that a ­long-term delay in ­response can be ex­pected.

    REQUEST DE­FERRED

    UM3 ROGER

    UM3 ROGER

    N

    RSPU-4

    Indication that the ­message is re­ceived.

    ROGER

    UM4 AFFIRM

    UM4 AFFIRM

    N

    RSPU-5

    Indication that ­ATC is responding ­positively to the ­message.

    AFFIRM

    UM5 NEGATIVE

    UM5 NEGATIVE

    N

    RSPU-6

    Indication that ­ATC is responding ­negatively to the ­message.

    NEGATIVE

    UM143 CONFIRM ­REQUEST

    N/A

    N

    RSPU-8

    Request to confirm ­the referenced re­quest since the ini­tial request was not ­understood. The re­quest should be ­clarified and resub­mitted.

    CONFIRM RE­QUEST

    TBL ENR 7.2-18Standard Response Downlink Message Elements (RSPD)

    CPDLC Message Sets

    Operational Definition in PANS-ATM (Doc 4444)

    FANS 1/A

    ATN B1

    Response

    Message ­Element ­Identifier

    Message Element ­Intended Use

    Format for Mes­sage Element Dis­play

    DM0 WILCO

    DM0 WILCO

    N

    RSPD-1

    Indication that the ­instruction is un­derstood and will ­be complied with.

    WILCO

    DM1 UNABLE

    DM1 UNABLE

    N

    RSPD-2

    Indication that the ­instruction cannot ­be complied with.

    UNABLE

    DM2 STANDBY

    DM2 STANDBY

    N

    RSPD-3

    Indication that the ­message will be re­sponded to shortly.

    STANDBY

    DM3 ROGERNote – ROGER is ­the only correct re­sponse to an uplink ­free text message.

    DM3 ROGER

    N

    RSPD-4

    Indication that the ­message is re­ceived.

    ROGER

    DM4 AFFIRM

    DM4 AFFIRM

    N

    RSPD-5

    Indication of a pos­itive response to a ­message.

    AFFIRM

    DM5 NEGATIVE

    DM5 NEGATIVE

    N

    RSPD-6

    Indication of a neg­ative response to a ­message.

    NEGATIVE

    TBL ENR 7.2-19Supplemental Uplink Message Elements (SUPU)

    CPDLC Message Sets

    Operational Definition in PANS-ATM (Doc 4444)

    FANS 1/A

    ATN B1

    Response

    Message ­Element ­Identifier

    Message Element ­Intended Use

    Format for Mes­sage Element Dis­play

    UM164 WHEN ­READY

    N/A

    NE

    SUPU-1

    Indication that the ­associated instruc­tion is to be execut­ed when the flight ­crew is ready.

    WHEN READY

    UM165 THEN

    N/A

    NE

    N/A

    Used to link two ­messages, indicat­ing the proper or­der of execution of ­clearances/ instruc­tions.

    N/A

    UM166 DUE TO ­TRAFFIC

    N/A

    NE

    SUPU-2

    Indication that the ­associated message ­is issued due to the ­specified reason.

    DUE TO (specified ­reason uplink)

    UM167 DUE TO ­AIRSPACE RE­STRICTION

    N/A

    NE

    SUPU-2

    Indication that the ­associated message ­is issued due to the ­specified reason.

    DUE TO (specified ­reason uplink)

    UM168 DISRE­GARD

    N/A

    R

    N/A

    The indicated com­munication should ­be ignored.The previously sent ­uplink CPDLC ­message shall be ­ignored. DISRE­GARD should not ­refer to a clearance ­or instruction. If ­DISREGARD is ­used, another ele­ment shall be ­added to clarify ­which message is to ­be disregarded.

    N/A

    UM176 MAIN­TAIN OWN SEP­ARATION AND ­VMC

    N/A

    W/U

    N/A

    Notification that ­the pilot is respon­sible for maintain­ing separation from ­other traffic and is ­also responsible for ­maintaining Visual ­Meteorological ­Conditions.

    N/A

    TBL ENR 7.2-20Supplemental Downlink Message Elements (SUPD)

    CPDLC Message Sets

    Operational Definition in PANS-ATM (Doc 4444)

    FANS 1/A

    ATN B1

    Response

    Message Ele­ment Identifier

    Message Ele­ment Intended ­Use

    Format for ­Message Ele­ment Display

    DM65 DUE TO ­WEATHER

    DM65 DUE TO ­WEATHER

    N

    SUPD-1

    Indication that ­the associated ­message is is­sued due to ­specified rea­son.

    DUE TO (speci­fied reason ­downlink)

    DM66 DUE TO ­AIRCRAFT ­PERFOR­MANCE

    DM66 DUE TO ­AIRCRAFT ­PERFOR­MANCE

    N

    SUPD-1

    Indication that ­the associated ­message is is­sued due to ­specified rea­son.

    DUE TO (speci­fied reason ­downlink)

    TBL ENR 7.2-21Free Text Uplink Message Elements

    CPDLC Message Sets

    Operational Definition in PANS-ATM (Doc 4444)

    FANS 1/A

    ATN B1

    Response

    Message ­Element ­Identifier

    Message Element ­Intended Use

    Format for Mes­sage Element Dis­play

    UM169 (free text)

    N/A

    R

    N/A

    A message or part ­of a message that ­does not conform ­to any standard ­message element in ­the PANSATM ­(Doc 4444).

    N/A

    UM169 (free text) ­CPDLC NOT IN ­USE UNTIL FUR­THER NOTIFICA­TION

    N/A

    R

    N/A

    See Note

    N/A

    UM169 (free text) ­"[facility designa­tion]" (for Altime­ter reporting Sta­tion)

    N/A

    R

    N/A

    See Note

    N/A

    (free text) "[facility ­designation] AL­TIMETER MORE ­THAN ONE ­HOUR" OLD

    N/A

    R

    N/A

    See Note

    N/A

    UM169 (free text) ­DUE TO WEATH­ER

    N/A

    R

    N/A

    See Note

    N/A

    UM169 (free text) ­REST OF ROUTE ­UNCHANGED

    N/A

    R

    N/A

    See Note

    N/A

    (free text) TRAF­FIC FLOW MAN­AGEMENT ­REROUTE

    N/A

    R

    N/A

    See Note

    N/A

    TBL ENR 7.2-22Free Text Downlink Message Elements

    CPDLC Message Sets

    Operational Definition in PANS-ATM (Doc 4444)

    FANS 1/A

    ATN B1

    Response

    Message ­Element ­Identifier

    Message Element ­Intended Use

    Format for Mes­sage Element Dis­play

    DM67 (free text)Note – Medium ­(M) alert attribute.

    N/A

    Y

    N/A

    N/A

    N/A

    DM68 (free text)Note 1. – Urgency ­or Medium (M) ­alert attribute.Note 2. – Selecting ­any of the emer­gency message ele­ments will result in ­this message ele­ment being en­abled for the flight ­crew to include in ­the emergency ­message at their ­discretion.

    N/A

    Y

    N/A

    N/A

    N/A

    TBL ENR 7.2-23System Management Uplink Message Elements (SYSU)

    CPDLC Message Sets

    Operational Definition in PANS-ATM (Doc 4444)

    FANS 1/A

    ATN B1

    Response

    Message ­Element ­Identifier

    Message Element ­Intended Use

    Format for Mes­sage Element Dis­play

    UM159 ERROR ­(error information)

    UM159 ERROR ­(error information)

    N

    SYSU-1

    System-generated ­notification of an ­error.

    ERROR (error in­formation)

    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.

    N

    SYSU-2

    System-generated ­notification of the ­next data authority ­or the cancellation ­thereof.

    NEXT DATA AU­THORITY (facility ­designation[O])

    UM161 END SER­VICE

    N/A

    NE

    N/A

    Notification to the ­avionics that the ­data link connec­tion with the cur­rent data authority ­is being terminated.

    N/A

    UM162 SERVICE ­UNAVAILABLE

    N/A

    NE

    N/A

    Notification that ­the ground system ­does not support ­this message.

    N/A

    TBL ENR 7.2-24System Management Downlink Message Elements (SYSD)

    CPDLC Message Sets

    Operational Definition in PANS-ATM (Doc 4444)

    FANS 1/A

    ATN B1

    Response

    Message ­Element ­Identifier

    Message Element ­Intended Use

    Format for Mes­sage Element Dis­play

    DM62 ERROR (er­ror information)

    DM62 ERROR (er­ror information)

    N

    SYSD-1

    System-generated ­notification of an ­error.

    ERROR (error in­formation)

    DM63 NOT CUR­RENT DATA AU­THORITY

    DM63 NOT CUR­RENT DATA AU­THORITY

    N

    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

    DM64 (ICAO facil­itydesignation)Note – Use by ­FANS 1/A aircraft ­in B1 environ­ments.

    N/A

    N

    N/A

    System-generated ­notification that the ­ground system is ­not designated as ­the next data au­thority (NDA), in­dicating the identi­ty of the current da­ta authority (CDA). ­Identity of the ­NDA, if any, is al­so reported.

    N/A

    TBL ENR 7.2-25Additional Uplink Messages

    CPDLC Message Sets

    Operational Definition in PANS-ATM (Doc 4444)

    FANS 1/A

    ATN B1

    Response

    Message ­Element ­Identifier

    Message Element ­Intended Use

    Format for Mes­sage Element Dis­play

    UM176 MAIN­TAIN OWN SEP­ARATION AND ­VMC

    N/A

    W/U

    N/A

    Notification that ­the pilot is respon­sible for maintain­ing separation from ­other traffic and is ­also responsible for ­maintaining Visual ­Meteorological ­Conditions.

    N/A

    TBL ENR 7.2-26Additional Downlink Messages

    CPDLC Message Sets

    Operational Definition in PANS-ATM (Doc 4444)

    FANS 1/A

    ATN B1

    Response

    Message ­Element ­Identifier

    Message Element ­Intended Use

    Format for Mes­sage Element Dis­play

    DM74 REQUEST ­TO MAINTAIN ­OWN SEPARA­TION AND VMC

    N/A

    N

    N/A

    States a desire by ­the pilot to provide ­his/her own separa­tion and remain in ­VMC.

    N/A

    DM78 AT (time) ­(distance) (tofrom) ­(position)

    N/A

    N

    N/A

    At the specified ­time, the aircraft's ­position was as ­specified.

    N/A