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CPDLC Checklist

Communications

One of the odd things about the CPDLC approval process is the FAA leaves the checklist up to you but doesn't know enough about data link to really QC yours. The other problem is that the system is so new that the ICAO and various regional authorities placed a number of unnecessary requirements into the system.

So now that we've had some time with it, the ICAO has released a new version of the so-called "GOLD Manual," the Global Operational Data Link Document. That has been replaced by ICAO Doc 10037 so it is time to update things. You will find a number of changes as a result on these pages:

Just look for any references to ICAO Doc 10037.

This checklist, and the printed Data Link Checklist, have also been updated.


 

  1. CPDLC Preflight Setup
  2. CPDLC Log On
  3. CPDLC Latency Timer
  4. Downlink Oceanic Clearance From DSP (Applies to all except NY Oceanic)
  5. Downlink Oceanic Clearance from NY Oceanic (via CPDLC)
  6. CPDLC Crossing an FIR Boundary
  7. CPDLC Coast Out
  8. CPDLC Crossing an OCA Boundary
  9. Switch CMF (If Data Link Frozen)
  10. Force SATCOM / Disable VHF DATA
  11. Make a SATCOM Short Code Call
  12. Constrain a Satellite
  13. Unconstrain a Satellite
  14. Exit CPDLC and ADS-C Airspace

CPDLC Preflight Setup

If you use CPDLC a lot, most of this becomes second nature. If, like me, your international flying is rarely more than a trip a month, you will learn to rely on these checklists. The preflight setup is pretty important, missing a step here could doom you to a crossing on HF.

Oh yes, this checklist is available for download: Data Link Checklist.

Most of the photos are from my aircraft, the checklist procedures started from the Gulfstream suggestion, handed to us in the form of a photocopy three generations removed from the original and doctored as we saw fit. Of course this checklist is for a Gulfstream G450, it probably needs some adjusting for other aircraft.

Flight Bag

Ensure you have the following either in paper, on the EFB, or your iPad:

Review the Latest ICAO NAT Ops Bulletins

ICAO NAT Ops Bulletins

This is a good source of the latest changes affecting data link operations in the North Atlantic.

Note: I've not seen a requirement for this anywhere, but our FSDO required this be specified in our checklist as part of our LOA approval. Besides, I think it is a good idea.

ATC Flight Plan

  • Verify Block 7 — Aircraft Identification agrees with FMS Flight ID
  • (IAW ICAO Doc 10037, ¶4.2.1.2)

  • Verify Block 10A — Equipment Code contains “J3” and "J5" – Data Link System
  • Verify Block 10B — Equipment Code contains “D1” – ADS

Master Document / En Route Charts

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Figure: CPDLC/ADC-C Logon Addresses, from ICAO Doc 10037, Figure 401.

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Figure: Data Link Services by CTA, from ICAO Doc 10037, Appendix B, Table B-NAT-1.

  • Annotate FIR boundaries
  • Check FIRs versus GOLD Appendix B and make note of:
    • CPDLC status
    • ADS-C status
    • AFN address
    • Any instructions under “Remarks”

There are international procedures courses that preach making note of the ATSU addresses and checking that in your CPDLC pages. I've not found a requirement for that and after doing this for a few years have never found it to be useful.

Confirm COM/NAV3 in Data Mode

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Downlink the Flight Plan

(This confirms the data link is working.)

1. Press DLK and select FLT PLAN.

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2. Enter the flight plan number.

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3. Press SEND RQST

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4. The system responds "SENDING"

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5. When the flight plan is downlinked you will see "FLT PLAN RECEIVED" in the MCDU scratch pad. Press FPL REVIEW.

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6. Press ACTIVATE.

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Check VHF Data Link (VDL)

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  • DLK > SYSTEM > DATALINK MGR

If data link is in GND VHF (VDL) mode, test as follows. Otherwise, if data link is SAT, check VHF (VDL) when airborne.

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If GND VHF (VDL) mode is not available from your current ground location, as shown, check VHF (VDL) when airborne.


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DLK > STATUS > TEST


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DATALINK SEND


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The system responds "SENDING"


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You should immediately be notified of a MESSAGE UPLINK.


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You should have two messages as a result.


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The first, the uplink, is simply the test going out.


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The second confirms your data link was received over VHF.


Confirm FMS Settings for CPDLC

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Confirm Flight ID entered into TCAS details page of FMS agrees with Block 7 of Flight Plan


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Confirm data link is operational:

  • DLK
  • SYSTEM
  • DATALINK MGR
  • VHF and SATCOM available

CPDLC Log On

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Figure: Initial AFN Logon, from FANS-1/A Operations Manual, ¶4.3.4., Figure 2.

So long as you are NLT 10 minutes and NET 25 minutes, the log on process is pretty quick, which is to say you will see the "ACCEPTED" message. "ATC COMM ESTABLISHED" happens just prior to getting to the airspace and "ADS ESTABLISH" as you are entering. (Remember, CPDLC is analogous to voice contact, ADS to radar contact.) If you are very close to data link airspace, say at EINN about to head west, you might have to do this while still on the ground.

Most of the photos are from my aircraft, the checklist procedures started from a Gulfstream example, handed to us in the form of a photocopy three generations removed from the original and doctored as we saw fit. Of course this checklist is for a Gulfstream G450, it probably needs some adjusting for other aircraft.

When to Log On

[ICAO Doc 10037, ¶4.2.2]

  • When operating outside data link airspace, the flight crew should initiate a logon 10 to 25 minutes prior to entry into airspace where data link services are provided.
  • Note.— When departing an aerodrome close to or within such airspace, this may require the logon to be initiated prior to departure.

  • Where a data link service is only provided in upper airspace and where local procedures do not dictate otherwise, the flight crew should log on to that ATS unit in whose airspace a data link service will first be used.
  • When failure of a data link connection is detected, the flight crew should terminate the connection and then initiate a new logon with the current ATS unit.

Log On (G450)

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Go to ATC LOG ON STATUS PAGE (DLK > ATC LOGON)

  • Ensure FLT ID and TAIL NO are correct
  • IAW: ICAO Doc 10037, para;4.2.1.

  • Ensure ADS ARMED
  • Ensure ADS EMERGENCY mode OFF (goes to OFF when first ARMED)
  • On second page, ensure ATC COMM is ARMED (“ATC COMM” is Honeywell’s name for CPDLC)
  • Back to first page, enter LOGON ID for FIR from ICAO Doc 10037 Appendix B, En Route Charts, or GAC-OMS-4.
  • SEND

You see should “ACCEPTED” on the LOGON field; the ACT CTR (Active Center) remains blank until our flight is handed over to this center.

All communications domestically will be over VHF until the day domestic centers adopt CPDLC and ADS will most likely not be used when radar coverage exists.

Once handed over to an ATSU with CPDLC, you should see “ATC COMM ESTABLISHED” in the scratch pad, the LOGON TO field goes blank, and the center’s identifier in the ATC CTR field.

ATC Comm Established (G450)

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Sometime prior to airspace entry, you should see "ATC COMM ESTABLISHED" and the ACT CTR field should indicate the data link FIR. Page 2 will show ATC COMMM is ACTIVE.

ADS Established (G450)

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If you are also in a location with ADS, you will also receive notification ADS ESTABLISHED and the ADS will go from ARMED to ACTIVE. You will probably not see this domestically and there are still a few oceanic areas with CPDLC but without ADS.

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You should review the ADS Contracts by going to NAV > ATC > ADS REVIEW

All of the periodic contracts will be listed except for the "Basic" data group which exists for all contracts and includes latitude, longitude, altitude, time, TCAS health, number of long range nav systems, and the nav system accuracy.

Note that the WPT CHG trigger means way point position reports will be made automatically.

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Note that the order of the pages depends on the order the contracts were received, you may get the event contracts first or the periodic, and they may be mixed between ATSUs.

CPDLC Confirmation (G450)

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Some ATSUs will send a confirmation:

NAV > ATC pulls up the confirmation message. Review page 2, ACCEPT, and SEND.
You are now logged on.

You might get a latency timer message and will need to respond. (This requirement should eventually disappear as the older equipment on some airliners is eventually replaced.)

CPDLC Latency Timer

Early CPDLC aircraft and ground systems, I am told, could get confused if a message became delayed so some aircraft systems were fitted with latency timers to evaluate the time delay from when the message was sent. Newer aircraft don't need such systems because the timing is already considered. Nevertheless, a newer aircraft systems could be querried by older ground systems so crew need to know how to respond. Here's how to do that on a Gulfstream.

The checklist procedures started from a Gulfstream example, handed to us in the form of a photocopy three generations removed from the original and doctored as we saw fit. Of course this checklist is for a Gulfstream G450, it probably needs some adjusting for other aircraft.

Message Latency Timer Background

[ICAO Doc 10037, para;2.1.2.6]

  • An ATS unit may implement automation to support use of a message latency monitor on the aircraft. The extent to which automation supports controller procedures that use the message latency monitor is a local matter.
  • The use of the message latency monitor, available on all ATN B1 aircraft and FANS 1/A+ aircraft, can provide the ANSP a means to mitigate the effects of a delayed CPDLC message that is delivered to the aircraft, and contributes to meeting the safety requirements for the ATS unit and the aircraft. Refer to ICAO Doc 9869 for specific safety requirements associated with each RCP specification.

Latency Timer Message Response

[ICAO Doc 10037, Table 4-1.]

There are disparities in what the actual message from ATC will say, much of it from older publications that have not caught up with the most recent incarnation of ICAO Doc 10037. As shown below, current guidance says the message will read: "LATENCY TIME VALUE ____" where the time value is given. Guidance used to be that the message would read: "CONFIRM MESSAGE LATENCY TIMER OFF" as shown in the photo below. If you see anyting about a latency time if you don't have a latency timer, proceed as your manufacturer advices. In the case of the Gulfstream 450:

  • ATS unit message: LATENCY TIME VALUE (latency value)
  • Flight crew message: ROGER and append with TIMER NOT AVAILABLE.

I've never seen this but have been warned about it and the response advocated was to accept (ROGER) the uplink [free text] message and append the [free text] with TIMER NOT AVAILABLE.

G450 Procedures

Because the G450 Data Link does not have a latency timer, older ground systems may be confused by the lack of a response and you could be asked to confirm the latency timer is off. (These are Gulfstream provided photos.)

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The message could also be phrased to note the uplink timer delay:

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You need to respond using free text.

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Downlink Oceanic Clearance From DSP (Applies to all except NY Oceanic)

This is how we down linked our oceanic clearances before we knew anything about CPDLC, it is basically coming from the "Data Link Service Provider," which means somebody one position removed from ATC. As of January 2014, this is how you downlink your oceanic from everyone except New York Center.

For that, see: CPDCL - Downlink Oceanic Clearance from NY Oceanic (via CPDLC).

Eastbound North Atlantic Notes

[FMS QTL]

  • Gander ACC sends the clearance to the GDC 10 to 60 min prior to aircraft entry into oceanic airspace. Gander ACC generally sends the clearance by 70° West longitude.
  • For aircraft departing Gander (CYQX), Goose Bay (CYYR), and St. John's (CYYT) airports, Gander ACC sends the oceanic clearance to the GDC at the same time it sends the departure clearance to the tower. Read back of the oceanic clearance is given to the tower, after which the tower issues the departure clearance.
  • With automatic position reports enabled, the GDC automatically sends the clearance to the aircraft as a datalink message as soon as it is received from Gander ACC.
  • If automatic position reports are disabled, the flight crew must request the clearance. Begin requesting the clearance approaching 70° West longitude, but if the clearance is not received by 25 min prior to entry into oceanic airspace, contact Gander ACC on the appropriate voice frequency.
  • If the GDC has received the oceanic clearance from Gander ACC, the clearance is sent to the aircraft as a datalink message. If the GDC has not received the oceanic clearance from Gander ACC, a datalink message indicating that the oceanic clearance has not been received from Gander ACC and that the oceanic clearance can be requested again in 10 min is sent to the aircraft.
  • Multiple oceanic clearance requests can be sent until 25 min prior to entry into oceanic airspace. Oceanic clearances are valid for 30 min beyond the issue time and voice read back of oceanic clearances is required.

Westbound North Atlantic Notes

[FMS QTL]

  • Delivery of oceanic clearances by way of datalink for westbound transatlantic flights for the Shanwick Oceanic Control Area (OCA) is known as Oceanic Route Clearance Authorization (ORCA) and requires that the aircraft be registered with the GDC for the service.
  • ORCA does not support use of variable call signs. The flight crew should request the clearance by way of datalink between 30 and 90 min prior to entry into the Shanwick OCA. Shanwick normally responds to the clearance request with a message indicating that the clearance should be received within the next 15 min. Shanwick then sends the clearance to the aircraft, which contains:
    • The aircraft registration
    • Entry point, ETA at the entry point
    • Mach number
    • Flight level
    • Route
    • Destination.
  • The flight crew must promptly acknowledge the clearance by way of datalink, by line selecting ACKNOWLEDGE on the message page containing the clearance. Failure to promptly acknowledge the clearance results in cancellation of the clearance transaction and requires that Shanwick be contacted by voice. Upon receipt of the clearance acknowledgement, Shanwick sends a message to the aircraft confirming the clearance. If this message is not received, Shanwick must be contacted by voice. If the flight crew requests a new clearance or if Shanwick requires a change to an existing clearance, one or more reclearances may be received by the flight crew. These reclearances are annotated RECLEARANCE 1, RECLEARANCE 2, etc., although may not necessarily be numbered consecutively.

G450 Procedures: Oceanic Clearance from a DSP

How you get a data link oceanic clearance everywhere in the world except from NY Center

[G450 Aircraft Operating Manual, §2B-21-40, ¶2.F.] Delivery of oceanic clearances by way of datalink for eastbound transatlantic flights is available from Gander Area Control Centre (ACC) to EPIC CMF-equipped aircraft. The aircraft, including any variable call signs, must be registered through the GDC with Gander. When flight planning, ensure that the phrase AGCS EQUIPPED (AGCS is an acronym for air-to-ground communication system) is included in the ATC remarks section of the filed flight plan. This remark informs Gander ACC that the flight crew desires to receive the oceanic clearance by way of datalink.

The book says to add "AGCS EQUIPPED" for coast out with Gander and we've always done it that way. This apparently inhibits your CPDLC Acknowledge function and will end up with you having to do a voice readback. SATCOM-Direct recommends you leave it out in a G450 or G550.

More about this: SATCOM-Direct AGCS Memo.

All oceanic areas, except New York, deliver oceanic clearances through a data link service provider, not CPDLC. Your clearance may come unsolicited. If not, download through the Aeronautical Operational Communication (AOC) page of the FMS by pressing the DLK key:

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Photo: MCDU AOC (DLK) Menu, from Eddie's aircraft.

Press ATS (LSK 2R)

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Photo: MCDU ATS Menu, from Eddie's aircraft.

Select OCEANIC REQ (LSK 4L)

These AOC services are known by most airlines as ACARS. The Air Traffic Services Menu is where you will find oceanic options.

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Photo: MCDU CLX Page, from Eddie's aircraft.

The ENTRY POINT and ENTRY TIME blanks are mandatory. The REQ MACH and REQ FL are taken from the FMS and may be changed if needed.

Once the mandatory entries are made you will get at SEND prompt at LSK 6R. Pressing SEND will result in a "SENT" line with the time.

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Photo: MCDU Oceanic Clearance, from Eddie's aircraft.

When the clearance is received the scratch pad will say "ATC MESSAGE" and then pressing DLK will give you the clearance page.

Acknowledge the clearance and print.

Downlink Oceanic Clearance from NY Oceanic (via CPDLC)

As of January 2017, New York Center is the only place you can get your oceanic clearance via CPDLC. For everywhere else, see: CPDCL - Downlink Oceanic Clearance from NY Oceanic (via CPDLC).

You normally get your oceanic clearance from an HF radio operator or from a Data Link Service Provider (DSP). The one exception today is from New York Oceanic, who prefer to send your clearance directly via CPDLC.

This offers you the advantage of down linking the exact clearance into your FMS flight plan, avoiding the common error of flying your preprogrammed flight plan and not your clearance.

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You will have already logged on and received ADS contracts from New York. You will get the usual ATC message alert:

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The ATC Index message reveals the clearance:

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You now only have 60 seconds to respond and if you don't, the next message will likely be holding instructions. You are best off reviewing it very quickly, selecting ACCEPT, then SEND, and only then REVIEW carefully.

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When you review it, you are likely to see "LL01" and so forth where you were hoping to see a series of latitudes/longitudes or better yet the ARINC 424 Shorthand codes for the same. You should accept the clearance and send.

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Once you've accepted the clearance, an ACTIVATE prompt appears. You now can take a little more time to study the clearance in detail.

Selecting REVIEW allows you to see each page, including the series of LL01, LL02, and so on. You will also have a prompt for ATC CLEARANCE where you will see the clearance expressed with the full latitude and longitude of those LL01s and so forth.

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If you are satisfied this is what you want, you can select ACTIVATE and the points will be inserted into your flight plan.

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You will get a CONFIRM prompt before the points are inserted into your flight plan. All existing points will be pushed to the bottom and you will have some housecleaning to do.

Note: if the clearance is an exact match, you may want to refrain from using ACTIVATE to avoid losing the very tidy N3050 nomenclature.

CPDLC Crossing an FIR Boundary

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Figure: Address Forwarding Sequence, from ICAO Gold, figure 2-8.

If you are already logged on, crossing an FIR boundary should be automatic, you just need to make sure it all happens. If, for some reason, the next center does not log on correctly, it is up to you to make an initial log on or revert to voice procedures.

Normal Transfer of CPDLC Connection

[ICAO Doc 10037, ¶4.2.3]

  • Under normal circumstances, the current and next ATS units automatically transfer CPDLC and ADS-C services. The transfer is seamless to the flight crew.
  • Note.— The flight crew should not need to reinitiate a logon.

  • The flight crew should promptly respond to CPDLC uplink messages to minimize the risk of an open CPDLC uplink message when transferring to the next ATS unit.
  • Note.— If a flight is transferred to a new ATS unit with an open CPDLC message, the message status will change to ABORTED. If the flight crew has not yet received a response from the controller, the downlink request will also display the ABORTED status.

  • Prior to the point at which the current ATS unit will transfer CPDLC and/or ADS-C services, the flight crew may receive an instruction to close any open CPDLC messages.
  • When entering the next ATS unit’s airspace, the flight crew should confirm the successful transfer from the current ATS unit to the next ATS unit by observing the change in the active ATS unit indication provided by the aircraft system.
  • When required by local procedures, the flight crew should send RTED-5 POSITION REPORT (position report). Alternatively, the flight crew may be required to respond to a CPDLC message exchange initiated by the ATS unit.
  • Note.— Since FANS 1/A aircraft do not report that the downstream ATS unit has become the CDA, the only way to confirm that it has taken place is for the ATS unit to receive a CPDLC message from the aircraft (refer to Appendix B).

G450 Example

Before crossing an FIR boundary, you should get a conditional clearance to contact the next ATSU:

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The clearance is conditional, since it includes a condition when to execute. Accept the clearance, verify message, send. You will see on the LOGON/STATUS page the NEXT CTR field will have the next ATSU listed.

A check in with the older controller is not necessary, but you will have to check in with the new controller once crossing the waypoint indicated in the conditional clearance.

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When the next ATSU takes control, you will see ATC COMM ESTABLISHED and the ATSU going from NEXT CTR to ACT CTR.

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CPDLC Coast Out

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Figure: ATC Comm Established Message, from Eddie's aircraft.

Once you've logged on and have your oceanic clearance, the coast out process is fairly simple. The following is an expansion of the CPDLC coast out procedures in our CPDLC checklist.

G450 CPDCL Oceanic Coast Out Example

When given a hand off to HF, the initial steps are the same . . .

  • "November seven seven zero zero, contact Shanwick Radio on three four seven six primary or eight eight niner one secondary."
  • You thank them as usual, change frequencies, and check in with Shanwick . . .
  • "Shanwick Radio, November seven seven zero zero, CPDLC, Gander Next, flight level four one zero, request SELCAL check Alpha Bravo Charlie Delta."
  • The response should be along the following: "November seven seven zero zero, 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."
  • If the SELCAL checks, you do not need to monitor the HF. With good CPDLC, ADS-C, and a WAYPT contract, you shouldn't have to make HF position reports either.
  • You should see ATC COMM ESTABLISHED in the FMS and the ATSU in the ACT CTR field.
  • With most ATSU's around the world you will also need to send a position report. (This is not required in the North Atlantic.) Check the GOLD Appendix E Remarks to check an ATSU's requirement.
  • More about this: CPDLC Manual Position Report.

Regional Procedures

If only it were this easy! Each region seems to have its own peculiar procedures that you may or may not pick up in Appendix B of ICAO Doc 10037. When coasting out of Gander heading east, for example, the VHF radio operator may be the same person handling the HF duties and may ask you for a position report on VHF in lieu of your first position report on HF. The radio operator wants you to include the term "CPDLC" to understand you will be using data link. Yes, the radio operator should have that information via your filed flight plan. But I would include the term "CPDLC" just to be sure.

CPDLC Crossing an OCA Boundary

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Figure: Address Forwarding Sequence, from ICAO Gold, figure 2-8.

Crossing an OCA boundary might be as simple as crossing an FIR boundary, but there may be additional steps needed.

Check In Requirements

ICAO Gold, Appendix B, has regional and/or state-specific information that should be consulted prior to transiting these regions. A few extracts from the North Atlantic section, for example:

[ICAO Gold, Appendix B, ¶B.4.3.1.1.3]

  • If the flight enters an oceanic CTA followed by another oceanic CTA, the flight crew should, on initial contact:
    • not include a position report;
    • after the radio operator responds, request a SELCAL check and state the next CTA;
    • The radio operator will assign primary and secondary frequencies, perform the SELCAL check and designate the position and frequencies to contact the aeronautical radio station serving the next oceanic CTA. If the communications instructions are not issued at this stage, the crew should assume that the frequencies to use prior or upon entering the next CTA will be delivered at a later time by CPDLC or voice.
    • Example (Initial contact from an eastbound flight entering GANDER Oceanic)

      GANDER RADIO, AIRLINE 123, SELCAL CHECK, SHANWICK NEXT

      AIRLINE 123, GANDER RADIO, HF PRIMARY 5616 SECONDARY 2899, AT 30 WEST CONTACT SHANWICK RADIO HF PRIMARY 8891 SECONDARY 4675, (SELCAL TRANSMITTED)

      GANDER RADIO, AIRLINE 123, SELCAL OKAY, HF PRIMARY 5616 SECONDARY 2899. AT 30 WEST CONTACT SHANWICK RADIO, HF PRIMARY 8891 SECONDARY 4675

      It has been my experience that most Arinc radio operators accept this method routinely for airline traffic but not so for corporate aviation. For non-airline traffic, I recommend keeping the old practice of adding the term "CPDLC" in this transmission. I've witnessed radio operators getting "testy" with corporate pilots when assuming non-CPDLC operations. So, for example:

      GANDER RADIO, NOVEMBER 7700, CPDLC, SHANWICK NEXT, REQUEST SELCAL CHECK ALPHA BRAVO CHARLIE DELTA

      Note also that current guidance no longer requires you state your flight level for this initial call up.

  • If the flight will exit an oceanic CTA into continental airspace or surveillance airspace, on initial contact with the oceanic CTA, the flight crew should:
    • not include a position report;
    • after the radio operator responds, request a SELCAL check.
    • Example (Initial contact from an eastbound flight about to enter SHANWICK Oceanic)

      SHANWICK RADIO, AIRLINE 123, SELCAL CHECK

      AIRLINE 123, HF PRIMARY 2899 SECONDARY 5616 (SELCAL TRANSMITTED)

      SHANWICK RADIO, AIRLINE 123, SELCAL OKAY, HF PRIMARY 2899 SECONDARY 5616.

      It has been my experience that most Arinc radio operators accept this method routinely for airline traffic but not so for corporate aviation. For non-airline traffic, I recommend keeping the old practice of adding the term "CPDLC" in this transmission. I've witnessed radio operators getting "testy" with corporate pilots when assuming non-CPDLC operations. So, for example:

      GANDER RADIO, NOVEMBER 7700, CPDLC, REQUEST SELCAL CHECK ALPHA BRAVO CHARLIE DELTA

      Note also that current guidance no longer requires you state your flight level and the two points following oceanic exit for this initial call up.

  • Depending on which data link services are offered in the oceanic CTA and the operational status of those services, the aeronautical radio operator will provide appropriate information and instructions to the flight crew (see paragraph B.4.2.1.1 for information regarding associated aeronautical radio operator procedures).
  • If a data link connection cannot be established, maintain normal voice communication procedures. In the event of data link connection failure in a NAT CTA after a successful logon revert to voice and notify the appropriate radio station. Inform AOC in accordance with established problem reporting procedures.
  • For ADS-C flights, the flight crew should not submit position reports via voice to reduce frequency congestion, unless requested by aeronautical radio operator.
  • ADS-C flights are exempt from all routine voice meteorological reporting, however the flight crew should use voice to report unusual meteorological conditions such as severe turbulence to the aeronautical radio station.
  • For any enquiries regarding the status of ADS-C connections, flight crew should use CPDLC. Should the ATS unit fail to receive an expected position report, the controller will follow guidelines in paragraph 3.5.1.7 for late or missing ADS-C reports.
  • When leaving CPDLC/ADS-C or ADS-C-only airspace, the flight crew should comply with all communication requirements applicable to the airspace being entered.
  • If the flight crew does not receive its domestic frequency assignment by 10 minutes prior to the flight’s entry into the next oceanic CTA, the flight crew should contact the aeronautical radio station and request the frequency, stating the current CTA exit fix or coordinates.

You should also check the Jeppesen Airway Manual State Rules and Procedures pages for CPDLC particulars for each region you will transit. For example, when flying the North Pacific Routes:

[Jeppesen Airway Manual, State Rules and Procedures, North Pacific (NOPAC), 7 Jan 2011] Aircraft with an active ADS connection should make one CPDLC position report over the FIR boundary and discontinue CPDLC waypoint reporting after the FIR report.

G450 Example

The first sign of crossing an OCA boundary, such as from Shanwick to Gander, will be the arrival of new ADS contracts to add to the current center's list.

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The new contracts push to the front and you can see the new center's address and it is now asking only for two contracts: the basic contract and one for meteorological data.  When the new center takes over, you will get the laundry list of event contracts added:

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And finally:

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Your HF call will be something like:

"Gander Radio, November seven seven zero zero, CPDLC, CARPE, REDBY, flight level four one zero, request SELCAL check alpha, bravo, charlie, delta."

Note: if you will be leaving oceanic airspace after this OCA, include the last two fixes on the cleared route.

Switch CMF (If Data Link Frozen)

We've had this happen a few times. We failed to get a log on with CPDLC even with the ADS-C logged on okay. Switching from one CMF to the other fixed what ailed us.

CMF Explained

[G450 Aircraft Operating Manual, §2B-21-30, ¶4.] The pilot can request GDC services by way of datalink through the Honeywell PLANEVIEW communications management function (CMF) datalink platform. This is a two-way data communications system between aircraft and ground systems. A complete datalink communication generated either manually or automatically is referred to as a datalink message. Messages from the aircraft to the ground are referred to as downlink messages and messages from the ground to the aircraft are referred to as uplink messages.

[G450 Aircraft Operating Manual, §2B-21-40, ¶1.]

  • As part of the PLANEVIEW integrated avionics system, the CMF is a next generation datalink platform designed for both software flexibility and hardware expandability. The CMF communicates primarily through a very high frequency (VHF) transceiver, although airborne equipment may, as an option, include a Satellite Data Communication System (SDCS) to provide datalink capability by way of ultra high frequency (UHF) transmissions.
  • By default, the PLANEVIEW CMF communicates by way of the land-based ACARS VHF network, which includes the Aeronautical Radio, Inc. (ARINC) and SITA subnetworks. Based on position information provided by the aircraft FMSs, the CMF automatically tunes to the appropriate subnetwork. In areas where VHF coverage is unavailable, the CMF may use the Inmarsat Aero-H, Aero-H+, or Aero-I satellite UHF networks. This provides both packet mode (datalink) and circuit mode (voice and data) capabilities to the aircraft. The CMF switches to and from the satellite UHF network based on the availability of land-based VHF network coverage.

[G450 Aircraft Operating Manual, §2B-21-60]

  • The CMF features a manual switching capability that permits the flight crew to select either CMF1 or CMF2 as the active CMF. This is provided primarily as a means to force a nonresponsive CMF to relinquish control to the other CMF.
  • When a manual switch is attempted and the standby CMF is functional, the active CMF becomes the standby CMF and the standby CMF becomes the active CMF. The CMF operation is not synchronized between CMF1 and CMF2 so any logged data or new messages are lost upon switching. Pilot-entered selections return to default settings when the standby CMF becomes active.
  • If a manual switch is attempted and the standby CMF is unable to become active, the active CMF is set to standby for approximately three seconds and then resumes control. During the course of switching to standby and back to active, the active CMF is reset. The reset of the active CMF results in all logged data and new messages to be lost.
  • If a manual switch is attempted due to a lock-up of the active CMF and the standby CMF is unable to become active, an attempt to reset the active CMF is made in order to clear the lock-up condition. Resolution of the lock-up condition is dependent on the cause of the lock-up.

The CMF is a mix of hardware and software and every now and then, as the operating manual says, it locks up. The following procedure is the fix.

Switching CMF's

As noted above, manually switching CMFs will result in losing any logged data or new messages. You should consider recording your OUT and OFF times, and your departure fuel. You should also attempt to print any messages you think you might need.

Step 1: Select MENU key.

images

Photo: MCDU Menu Page, from Eddie's aircraft.

Step 2: Select MISC key, LSK 1L.

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Photo: MCDU Menu Misc Page, from Eddie's aircraft.

Step 3: Toggle LSK 5L to select the other CMF.  It will take a few seconds but you should see the change reflected on the screen.

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Photo: MCDU Menu CMF2 Page, from Eddie's aircraft.

Once this is done, check the ATC LOGON STATUS page, NAV > ATC (LSK 1R)

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Photo: ATC Log On Status Page, from Eddie's aircraft.

Force SATCOM / Disable VHF DATA

Rationale

The CMF should automatically choose SATCOM when there are no VHF data stations available but sometimes it needs a kick to the head to realize that. This procedure denies it the VHF Data, providing that swift kick to the head.

Force SATCOM

Press the RADIO key and then NEXT to get the RADIO 2 / 2 page.

images

Photo: MCDU Radio 2/2 Page, from Eddie's aircraft.

Press LSK 6L (COMNAV3) to get the COM / NAV 3 page.

images

Photo: MCDU Menu Page, from Eddie's aircraft.

Press LSK 2R to switch MODE from DATA to VOICE.

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Photo: MCDU Menu Page, from Eddie's aircraft.

Make a SATCOM Short Code Call

You can contact most oceanic radio centers for any emergency or non-routine situation, but most of these are accessed by a 6-digit "short code." You can dial a short code or a regular voice number through any of the MCDU's.

Make a SATCOM Short Code Call

Select the Menu Page with the MENU key.

From this page select the SATCOM Main Menu by pressing LSK 6L.

images

Photo: MCDU Menu Page, from Eddie's aircraft.

Select the directory with LSK 6R

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Photo: MCDU SATCOM Main Menu Page, from Eddie's aircraft.

Type in the desired short code. We are using 431613, the short code for Gander Radio, in the example.

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Photo: MCDU SATCOM Directory with 431613 In Scratch Pad, from Eddie's aircraft.

If the number is in a valid format, you will see the number displayed with "DIALING." To end the call, press LSK 2R.

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Photo: MCDU SATCOM Directory Dialing 431613, from Eddie's aircraft.

Example Oceanic Numbers

The oceanic numbers are given on some en route charts and are reproduced here:

  • Gander Radio: 431613
  • New York Radio (ARINC): 436623
  • Iceland Radio (Emergency): 425101 or 425103
  • Iceland Radio (Com Failure): 425105
  • Santa Maria Radio: 426305 or 426302
  • Shanwick Radio: 425002

Dial a Regular Voice Number using an MCDU

You can make calls to regular voice numbers, those that are not 6 number short codes, by formatting the number as you would an international phone call. Since our aircraft is based in the United States, a call to Gander Radio which appears as 1-709-65155212 would be entered into the scratch pad as 017096515212.

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Photo: MCDU SATCOM Directory Dialing 017096515212, from Eddie's aircraft.

Making the Call

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Figure: G450 Audio Control Panel, from G450 Aircraft Operating Manual, §2B-22-40.

[G450 Aircraft Operating Manual, §2B-22-40.]

  • To interface with the SATCOM transceivers the audio panel is used to to select the SATCOM system and adjust the volume of the received audio. When communicating using the SATCOM system, the audio panel has annunciators that indicate an incoming call, a call on hold, and when a call is being connected. SATCOM can also be used to make a call.
  • The two SAT buttons are used to control the SATCOM telephone system. The rectangular button flashes and a chime sounds to indicate an incoming SATCOM call. Both the round and rectangular buttons remain on when the line is in use. The rectangular button is used to connect and disconnect the SATCOM calls. The pilot disconnects SATCOM by pushing the rectangular button again. At this time, all SATCOM annunciator lights go off.

Constrain a Satellite

Of course if you are going to constrain a satellite, you may need to know how to unconstrain it: Unconstrain a Satellite.

Satellite Log On Constrained Mode

[G450 Aircraft Operating Manual, §2B-22-40, ¶2.A.]

  • The SATCOM system is automatically turned on and begins attempting to log on as soon as power is applied during aircraft power up. The SDU supports two types of log-on: Automatic and Constrained Mode.
  • When the AES is in the automatic mode, the log-on GES/satellite/spot beam chosen is based on the GES preference. A GES with a preference level of zero is not considered for automatic log-on. The SDU allows the use of tied GES preferences. The SDU resolves tied preferences by selecting the GESs in descending order of satellite elevation. During GES selection, the set of GESs with the highest preference are initially processed to exclude those GESs associated with satellites not in view.
  • Constrained Log-On — Constrained log-on requires the user to manually select the GES to be used for log-on. The pilot command originates from the MCDU. The GES automatic preferences have no effect in the constrained log-on mode, and it is possible to execute a constrained log-on to a GES with a preference level of zero.
  • If the pilot has manually selected the log-on GES, thus also selecting the satellite, the SDU is constrained to search for the specific GES-related satellite channel used to identify the satellite frequency.

[FMS QTL] In certain situations it may be necessary to constrain a satellite for NAT operations. The recommended procedure is to constrain the satellite that corresponds to the NAT exit area. It has been recommended that when flying eastbound constrain the system to use the Atlantic East satellite. When flying westbound constrain the system to use the Atlantic West satellite.

Some people swear by this technique. We've never used it and have never had a problem. (That's why I had to draw most of these figures.)

G450 Constraining Satellites Procedure

Before ADS-C LOGON on the MCDU press the MENU key.

Press the SAT key (LSK 6L)

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Photo: MCDU Menu Page, from Eddie's aircraft.

Select SUBMENU (LSK 6L)

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Photo: SATCOM Main Menu page, from Eddie's notes.

Select LOG-ON (LSK 2L)

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Photo: SATCOM submenu, from Eddie's notes.

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Photo: SATCOM Logon Menu, from Eddie's notes.

[FMS QTL]

  • For NAT operations the recommended procedure is to constrain the satellite corresponding to the NAT exit area.
  • For GDC:
    • Eastbound constrain the system to use the Atlantic East satellite.
      AUSSAGUEL-AE
    • Westbound constrain the system to use the Atlantic West satellite.
      AUSSAGUEL-AW
  • For ARINC:
    • Eastbound constrain the system to use the Atlantic East satellite.
      EIK-AE
    • Westbound constrain the system to use the Atlantic West satellite.
      STHBURY/EIK-AW

    Select GES SEL (LSK 6L)

Select the satellite you wish to constrain, for the example we will constrain the Atlantic West Satellite so we press LSK 2L

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Photo: MCDU GES Selection Page, from Eddie's notes.

The SATCOM Logon page should now report "LOGGED-ON CONSTRAINED" and in our example the satellite switched to AOR-W.

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Photo: SATCOM Logon Menu with SATCOM constrained, from Eddie's aircraft.

Unconstrain a Satellite

If you are going to unconstrained a satellite, you may need to know how to constrain it again: Constrain a Satellite.

Satellite Log On Constrained Mode

[G450 Aircraft Operating Manual, §2B-22-40, ¶2.A.]

  • The SATCOM system is automatically turned on and begins attempting to log on as soon as power is applied during aircraft power up. The SDU supports two types of log-on: Automatic and Constrained Mode.
  • When the AES is in the automatic mode, the log-on GES/satellite/spot beam chosen is based on the GES preference. A GES with a preference level of zero is not considered for automatic log-on. The SDU allows the use of tied GES preferences. The SDU resolves tied preferences by selecting the GESs in descending order of satellite elevation. During GES selection, the set of GESs with the highest preference are initially processed to exclude those GESs associated with satellites not in view.
  • Constrained Log-On — Constrained log-on requires the user to manually select the GES to be used for log-on. The pilot command originates from the MCDU. The GES automatic preferences have no effect in the constrained log-on mode, and it is possible to execute a constrained log-on to a GES with a preference level of zero.
  • If the pilot has manually selected the log-on GES, thus also selecting the satellite, the SDU is constrained to search for the specific GES-related satellite channel used to identify the satellite frequency.

G450 Unconstraining Satellites Procedure

Press the SAT key (LSK 6L)

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Photo: MCDU Menu Page, from Eddie's aircraft.

Select SUBMENU (LSK 6L)

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Photo: SATCOM Main Menu page, from Eddie's notes.

Select LOG-ON (LSK 2L)

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Photo: SATCOM submenu constrained, from Eddie's notes.

Select AUTO LOG-ON (LSK 2L)

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Photo: SATCOM Logon Menu with SATCOM constrained, from Eddie's aircraft.

You should now be back to unconstrained.

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Photo: SATCOM Logon Menu, from Eddie's notes.

Exit CPDLC and ADS-C Airspace

[ICAO Doc 10037, ¶4.2.5]

  • Approximately 15 minutes after exiting CPDLC and/or ADS-C areas, the flight crew should ensure there are no active CPDLC or ADS-C connections. Ensuring that connections are not active eliminates the possibility of inadvertent or inappropriate use of the connections.
  • The flight crew should consult the current ATS unit prior to the manual termination of any ADS contract, even if it is suspected to be unnecessary or that its termination has failed.
  • In the event that the connection termination has failed, the flight crew should contact the ATS unit via voice or any other appropriate means.
  • Note.— ADS contracts are normally managed (e.g. established and terminated) by ATS units.

When exiting CPDLC and ADS-C airspace, ensure there is no active CPDLC connection by checking that the ACTIVE CENTER on the LOGON page is blank and that there is no active ADS-C connection.

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Photo: MCDU ATC Logon Page (No active centers), from Eddie's aircraft.

Book Notes

Portions of this page can be found in the book International Flight Operations, Part IV, Chapter 6.

References

Asia/Pacific Information Package, FAA Flight Technologies and Procedures Division (AFS-400), June 15, 2012

FANS-1/A Operations Manual, FAA Aeronautical Communications Aviation Safety (AVS), Version 6.0, 25 September 2008

Guidance Material for ATS Data Link Services in NAT Airspace, The North Atlantic FANS Implementation Group (NAT FIG), The North Atlantic Systems Planning Group (NAT SPG), Version 19.1, 14 September 2009

Gulfstream G450 Aircraft Operating Manual, Revision 35, April 30, 2013.

Gulfstream G450 Airplane Flight Manual, Revision 35, April 18, 2013

Gulfstream Operating Manual Supplement for G350, G450, G500, and G550 Airplanes, Supplement Number GAC-OMS-4, Future Air Navigation System (FANS 1/A), Automatic Dependent Surveillance (ADS-C), Controller Pilot Data Link Communications (CPDLC), Revision 1, July 1, 2012

ICAO Document 10037 AN/509 - Global Operational Data Link (GOLD) Manual, Advance edition (unedited), First Edition, 2016

SATCOM-Direct AGCS Memo, "Are You Properly Initiating the Oceanic Clearance Process?"

Revision: 20170502
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