CPDLC newbie question
 

Just upgraded the Global Express with, among other things, FANS and CPDLC.

The online Bombardier training clearly explained how to establish a CPDLC link to ATC but there is no guidance on what to do next or how to make a position report.

Q: After we establish a CPDLC link what next? Do we still check in on the HF for a SelCal test? How do position reports work? Does the system report our position automatically or do we use FMS to report position each time?

How would it work, for example, on a KOAK-PHNL flight within OAK FIR?

Thanks in advance for your reply.

I fly airlines but here is how it works in KZAK (Oakland) airspace.
Login about 20 minutes before the FIR if inbound or anytime after leaving 10,000ft climbing if outbound from US West Coast. Once logged on immediately send a position report. It doesnt matter what position, it is only to satisfy the ground station that it has "data authority". How you do that from your installation I don't know.
Don't send another position unless asked, you won't be in the Pacific. We do a SELCAL check with SanFrancisco pre flight or early in the flight and then just monitor. Entering Auckland, Nadi or Brisbane FIRs we don't even call, just monitor the HF by SELCAL.


So to reiterate on your KOAK-PHNL flight.
Leaving 10000 on climb log on to KZAK.
Once logged on send a position report (without being asked).
Get a SELCAL check from San Francisco who will also give you new frequencies to change to at 140W.
Now no further action required except for level change requests etc. If you don't climb the next interaction with CPDLC would probably be a message to contact HNL Center approaching the Oceanic boundary inbound.

Can't speak for west coast procedures but if you venture further afield there are differences across the FIRs. Many e.g. Gander/Shannon, don't demand any pilot initiated position reports at any stage unless the automation doesn't work. OTOH the Aussie FIRs always do demand a initial position report - and they will ask for it via the CPDLC. Generally in most parts of the world you simply log on, do the Selcal check and that's it ( though you may get a CPDLC ping asking you to acknowledge on some oceanic routes for FANS purposes). The CPDLC/FMC should silently handle the position reports, at the FIR boundary you switch to the next FIRs frequencies, do a selcal check and again, that's it.

ksjc,

My recommendation is get and have available the GOLD Manual for datalink ops--it'll answer your questions for each FIR. The first ATL crossing for me was an eyeopener; I had it out the whole time. It's weird the first, no radio work except at 30W.

GF

Be aware of the difference between CPDLC and ADS-C position reporting.
North Atlantic uses ADS only, they don't process CPDLC position reports at all. (ATC communication via CPDLC though)
In Asia and Australia CPDLC is used for position reporting.
ADS operations are normally completely transparent on most planes, if you are lucky the show you're connected, if very lucky with whom.
Feedback about outgoing position reports is often not visible to the pilot.

Some good info here that has answered some questions I had also. Thanks. Another one - has anyone experienced the issue where when you transit from a CPDLC supported FIR, to an FIR that doesn't support CPDLC and then subsequently back into a CPDLC supported FIR, that the FMS remains "locked" on the initial CPDLC FIR? I've found the only way to "unlock" the initial FIR is to select ATC CPDLC OFF (probably not the correct term, can't remember what the available selection actually was) and then re-enable it to allow login to the new FIR. Anyway, that was my workaround. Gotta say, it is the duck's nuts, simply awesome. Out of PHNL to YSSY - last time I spoke to someone was at TOPC until I was on VHF with Brisbane over Lord Howe Island. Never loved HF...
(By the way, I'm referring to GLEX)

Thanks all for the most helpful feedback.

Galaxy Flyer: Currently searching for the "Gold Manual".

ksjc,

It's the ICAO Global Data Link Document second edition 26 Apr 2013. PM an email address and I'll try to email it out of BA Flight Deck.

http://www.icao.int/APAC/Documents/e...D_2Edition.pdf

GF