CPDLC information required please...

[Jet Jockey A4]

Moderators feel free to move this thread to the proper location if required...

Looking for any information on CPDLC usage specifically on the initial radio contact with centres where CPDLC is used.

Are there specific radio protocols on initial contact with Gander or Shanwick when you use CPDLC? If there is a proper protocol where could I read up on it?

When you do a CPDLC position report, should you get an acknowledgement from Gander or Shanwick that they did indeed get that position report?

Is it normal with Gander to get the following message (as seen on our FMS);

"Free text... Message not supported by this facility"


Any other information or links to CPDLC information would be greatly appreciated.

Thank you.

[Wirbelsturm]

No you don't get confirmation of position reports. CPDLC is for clearances and requests. Normal to call the Oceanic/controller with 'Callsign, CPDLC, XXXX next' (where xxxx is your next oceanic control zone, i.e. NATS would normally be Shanwick with Gander next) then request frequencies if using HF for SELCAL check. Level changes, route clearances, re-routes, weather avoidance, frequency changes etc. are given over CPDLC with the ability to Accept, Reject and Cancel through the buttons mounted on the glareshield. (at least that's where they are on the 777).

If exiting NATS for example then you exit point plus the next waypoint after would normally be given.

Position reporting and automatic surveillance go on in the background. Occasionally you might get asked to report at a specific position, if so ATC will 'sometimes' (not Santa Maria!) acknowledge your position report but it isn't necessary.

[Jet Jockey A4]

Thank you Wirbelsturm...

That's what I thought on the position reports.

For the radio protocol on initial contact that is exactly what I have been doing.

When with Gander radio (on VHF) before coast out I would on my initial call in to them, I would give my call sign; say I'm CPDLC Shanwick next...

They would come back with Gander's HF assignments and Shanwick's HF assignments. We would then do the SELCAL check with Gander.

At 30W the CPDLC would switch to Shanwick, I would call up Shanwick on my HF freq and check in with my call sign, tell them I'm CPDLC and give them my exit point. Lastly a SELCAL check would be made.

Going westbound I would do the exact same thing.

On my two crossing Shanwick gave us our VHF assignment for our exit point by HF and not through the CPDLC... Is this normal?

While going westbound within Gander's FIR we got our VHF assignment over the CPDLC.

Just wondering why the difference in the two centres.

I'm also wondering if that Gander message of "Free text... Message not supported by this facility" as seen on our FMS CDU is a technical problem with our system or it is that Gander does not have the technology to send Free Text?

Our aircraft just got upgraded with CDPLC/FANS and I want to make sure everything is working correctly, thanks.

[Wirbelsturm]

"Free text... Message not supported by this facility"

I haven't seen that message before so I couldn't comment on whether it is an aircraft or a station restriction to be honest.

I think it is the whim of the controller as to whether you get your en-route freqs by HF (selcal) or CPDLC. If that aircraft is a 'new fit' then some controllers might just revert to type and call you on HF without realising you had the upgrade.

I believe that it is a new ATC rule that all NATS aircraft MUST have ADS/CPDLC to use the tracks. Hence the upgrade.

Believe me, it makes life so much easier/quieter!!!!!

Enjoy.

[Jet Jockey A4]

Thanks again...

Just found out by some ATC source here in Canada that Gander apparently does not support "Free Text messages"!

Will have to dig deeper to confirm this.

[John Boeman]

Useful info in this thread:
http://www.pprune.org/tech-log/455963-cpdlc-position-reports.html

[Jet Jockey A4]

John Boeman...

Thanks for the link, interesting info.

[Jet Jockey A4]

Waiting on documents from Gander which will be sent by the manager of the Gander facility later on today.

He clarified a few things for me. The reason I'm getting the "no free text message" is that when in the Gander FIR with your ADS-C system logged in and functioning you are not required to manually "send" a position report the ADS does it automatically.

Sending the position report manually by using the "send" key fools the system and the no free text message appears.

So it seems that while with Gander and Shanwick with ADS working all position reports are done automatically.

[rab-k]

ADS indeed makes manual sending of a CPDLC format report unnecessary. The problem with such CPDLC format reports are that they only appear at the controller's workstation and are unable to be copied to the respective HF radio operator's console nor indeed to the next receiving oceanic centre, which will normally receive a copy of the HF/ADS/FMC waypoint position report immediately prior to their boundary.

Can't speak for Gander, but the Shanwick kit sometimes displays the Lat/Lon from a CPDLC format report as XXXX which needless to say renders the report useless. l'll sometimes send a freetext up to a crew to advise them a CPDLC format report is neither required nor supported by EGGX should they repeatedly send such whilst I'm simultaneously receiving ADS-C reports.

[Jet Jockey A4]

Thank you rab-k.

[Keylime]

Jet Jockey:

You might find this link useful http://www.ibac.org/wp-content/uploads/2010/08/NAT-Doc-007_Edition-2011_17OCT11.pdf

This document GUIDANCE CONCERNING AIR NAVIGATION IN AND ABOVE THE
NORTH ATLANTIC MNPS AIRSPACE
Edition 2011 is about 130 pages and can answer almost any question about NMPS operation in the NAT.

[PIGDOG]

CPDLC is far from perfect. So Shanwick would have given you your exit VHF by voice because 1) it was successfully sent to your aircraft but wasn't acknowledged, or 2) the CPDLC connection failed.

Also, Shanwick Radio Officers will give you the exit freq if you're not going to be long in their airspace, for example, 44N20W 47N15W OMOKO. You'll be given the freq for OMOKO when you cross 45N and declare yourself CPDLC exit OMOKO.

[Natstrackalpha]

Hello mate.

There are numerous CPDLC procedures from various airlines all over the internet - it would do you well to read them, they are basically all the same, plus your company`s. Also, all the Oceanic pre-flight planning procedures, not to mention etops.

All about your pre-flight essentially and your (pre) coasting out checks.
There are MIL versions and civvy versions and one entity borrows or adapts from the other. It is quite a read and verily a subject in itself, if you are to avoid GNE!

CPDLC in itself is quite simple, the process of going Oceanic as regards who to call, on the ground and when, after you have submitted the flight plan is quite picky - you can ask them like, Shanwick, or you can look it up in the ENRoute or whatever they have nowadays.

Obviously, you`ve got your Pacific, N and S and the Atlantic. Bottomline, grab as much as you can. You will know it when you have got it.

Try searching under CPDLC+/- Oceanic Procedures. There are some fairly consolidated downloads, a couple of A4 sheets, yet packed with ESSENTIAL information.

Enjoy, its busy fun!

Oh by the way: Here`s one I know and love - there are Brit versions too - but if you are already `on it` then forgive me for being so basic.

Also -Natstrackalpha! - if you have flight planned, then phone, send a carrier pidgeon or ask ATC to tell Shanwick that you will be at your oceanic gate by a certain position and time, this seems logical, but it really niggles them, if you just flight plan, take off and turn up - trust me, I`m a potato.

http://www.faa.gov/pilots/intl/oceanic_ops/media/SampleOceanicChecklist.pdf

[MarkerInbound]

Here's the link to ICAO's Global Operations Document.

http://www.icao.int/APAC/Documents/edocs/GOLD_1st_Edition.pdf

It explains way more than a pilot cares to know. The list of FIRs using CPDLC in the appendix is in need of an update. Was flying over Chad a couple of months ago and checked in with N'Djamena. They asked if we were able CPDLC. We said yes and they gave us their log on code. The other pilot and I both wondered how Chad got CPDLC going. And then, since I wasn't going to have to talk on the radio for a while, I got something to eat.