Some aircraft manufacturers are better than others about providing a data link checklist tailored to their aircraft. In fact, some don't provide one at all. If you are in that boat, we can get you started.

— James Albright




This data link checklist was made for a Gulfstream G450 around 2013 and was tweaked a few times, last updated in 2017. You can download a PDF version here.


CPDLC Preflight Setup

  1. Ensure you have the following documents in paper form, EFB, or iPad:
    1. ICAO Global Operational Data Link Document (GOLD)
    2. GAC OMS-4
  2. Review latest ICAO NAT Bulletins
  3. Verify the following appears in your ICAO Flight Plan
    1. Block 7 - Aircraft ID agrees with FMS Flight ID
    2. Block 10A - Equipment Code "J3” and “J5” (Data Link System)
    3. Block 10B - Equipment Code "D1" (ADS)
  4. Master Document / En Route Charts
    1. Annotate FIR boundaries
    2. Check FIRs versus GOLD Appendix E and make note of:
      1. CPDLC status
      2. ADS-C status
      3. AFN address
    3. Any instructions under Remarks
  5. Confirm COM/NAV3 in Data Mode
  6. Verify Data Link works by any of the following methods:
    1. Downlink the flight plan
    2. Downlink D-ATIS
    3. Downlink PDC
    4. Downlink Terminal Wx
  7. Check AOC STATUS page 1/3
      1. If data link is GND VHF (VDL) test SATCOM (DLK > STATUS > TEST > DATALINK SEND)
      2. If data link is SAT check GND VHF (VDL) when airborne
  8. Confirm FMS Settings for CPDLC
    1. Confirm Flight ID entered into TCAS details page of FMS agrees with Block 7 of Flight Plan
    2. Confirm Data Link is Operational:
      2. VHF available
      3. SATCOM available


  1. When:
    1. On the ground at a departure airfield within 15 minutes of an OCA or FIR that supports CPDLC, you are expected to log on NET 45 minutes prior to takeoff.
    2. If you are unable to log on from the ground, wait until passing 10,000 feet. Log on to the current FIR unless you are within 15 to 25 minutes of the next FIR, then log on to the next FIR.
    3. If already airborne, log on to the next ATSU NET 45 minutes NLT 15 minutes from reaching their airspace.
  2. Log On Procedure
    2. Ensure FLT ID and TAIL NO are correct
    3. Ensure ADS ARMED
    4. Ensure ADS EMERGENCY mode is OFF
    5. On second page, ensure ATC COMM is ARMED
    6. On first page, enter LOGIN ID of FIR (From GOLD Appendix E, En Route Chart, or GAC-OMS-4)
    7. SEND
  3. You should see ACCEPTED on LOGON field
  4. Once handed over to an ATSU with CPDLC you should see:
  5. If you are also in an ADS location, you will see ADS ESTABLISHED and the ADS will go from ARMED to ACTIVE.

CPDLC Latency Timer Message Response

  2. The G-450 does not have a latency timer
  3. Respond using free text "TIMER NOT AVAILABLE"

Downlink Oceanic Clearance

  1. From a DSP (Everywhere except New York Oceanic)
    2. Set ENTRY POINT, ENTRY TIME, and adjust Req Mach and Req FL if required
    3. SEND
    4. ACKNOWLEDGE on receipt
  2. From NY Oceanic using CPDLC
    1. Will get the oceanic from NY Oceanic via ATC UPLINK message
    2. ACCEPT within 60 seconds
    3. REVIEW
    4. ATC CLEARANCE to interpret LLXX waypoints
    5. ACTIVATE to insert into FMS flight plan
    6. Remove extraneous waypoints at end of flight plan

CPDLC Crossing an FIR Boundary

  1. Before crossing an FIR boundary, you should get a conditional clearance to contact the next ATSU.
  2. Accept the clearance, send, but do not contact the next ATSU yet.
  3. On the LOGON/STATUS page you will see the NEXT CTR field has the next ATSU listed.
  4. When the next ATSU takes control, you will see ATC COMM ESTABLISHED
  5. A check-in with the departing controller is not necessary.
  6. At the waypoint listed, contact the new controller.

CPDLC Coast Out (North Atlantic Example)

  1. Establish log on NET 45 minutes, NLT 15 minutes prior to oceanic FIR
  3. When sent to HF, for example:
    ____________ Radio, November ______________________________, CPDLC, ________ Next, "Shanwick Radio, November one two three alpha alpha, CPDLC, Gander Next, flight level _______________, request SELCAL check ______________________________ flight level four one zero, request SELCAL check Alpha Bravo Charlie Delta" Note: the flight level and term “CPDLC” are no longer required but seem to be expected by most radio operators.
  4. If you also have ADS-C, you should hear: "November one two three alpha bravo, Shanwick Radio, SELCAL check OK, voice reports not required in Shanwick OCA, at 30 West contact Gander on three zero one six primary or five five niner eight secondary."
  5. For most ATSU’s around the world, you will also send a position report. (This is not required in the North Atlantic.) Check GOLD Appendix E Remarks for the ATSU’s requirements.

Crossing an Oceanic Boundary

  1. You should get new ADS contracts at least 15 minutes prior to the boundary.
  2. At the boundary you should get ATC COMM ESTABLISHED.
  3. If you will be leaving oceanic airspace after this OCA, include the last two fixes on the cleared route, for example:
    __________ Radio, November ____________________________, CPDLC, ________, ________, "Gander Radio, November one two three alpha alpha, CPDLC, CARPE, REDBY, flight level ________________ request SELCAL check ______________________________ flight level four one zero request SELCAL check alpha, bravo, Charlie, delta."
    Note: the flight level and term “CPDLC” are no longer required but seem to be expected by most radio operators.

Switch CMF (If data link frozen)

  1. Select MENU
  2. Select MISC
  3. Toggle LSK 5L to the other CMF. It will take a few seconds, but you should see the change reflected on the screen.

Force SATCOM / Disable VHF Data Mode

  1. RADIO Page 2/2
  2. COM / NAV 3

Make a SATCOM Short Code Call

  1. You can contact most oceanic radio centers using SATCOM for any emergency or non-routine situation. To dial the 6-digit short code from the MCDU:
    1. Select MENU>SAT
    2. Type the number in the scratch pad
    3. Push MAKE CALL (4L)
    4. The system dials the number
    5. To end the call, push END CALL (2R)
  2. The oceanic numbers are given on some en route charts and are reproduced here:
    1. Gander Radio: 431613
    2. New York Radio (ARINC): 436623
    3. Iceland Radio (Emergency): 425101 or 425103
    4. Iceland Radio (Com Failure): 425105
    5. Santa Maria Radio: 426305 or 426302
    6. Shanwick Radio: 4250002

Constrain a Satellite

  1. Under normal operations, constraining a satellite is not necessary. If, for some reason a particular satellite drops you, this might be helpful.
  2. Before ADS-C LOGON on the MCDU:
    1. MENU
    2. SAT (6L)
    3. SUBMENU (6L)
    4. LOGON (2L)
    5. GES (6L)
    6. Constrain the satellite in question
    7. LOGON (6L)
    8. GES (6L)
    9. Constrain the satellite in question
    10. LOGON (6L)

Unconstrain a Satellite

  1. MENU
  2. SAT (6L)
  3. SUBMENU (6L)
  4. LOGON (2L)
  5. AUTO LOGON (2L)

Exiting CPDLC and ADS-C Airspace

  1. The CPDLC connection and the ADS contract should terminate automatically.
  2. If not, switch both off