CPDLC position reports

[RandomPerson8008]

Hi,

I, and my company, are new to CPDLC. Obviously, we have published guidance but it doesn't cover everything.

My question is:

Does ATC typically expect the pilots to manually send position reports through the FMC's "ATC position report" function at compulsory reporting points, or does ATC get all the info they need automatically from the ADS uplink (which, as I understand it, gives them continuous aircraft position/altitude information through satcom datalink)? We have been using the manual report function just to be on the safe side, but have heard reports that some agencies like Gander do not expect or require it.

Also, what is the proper phraseology for indicating to a controlling agency that you have CPDLC capability on initial voice check in?

I have been saying something to the effect of:

-----------------------------------------------
Me: Nadi Control, Airline 1234 on 8861

Them: Airline 1234, Nadi Control, Go ahead.

Me: Airline 1234, position (FIR Boundary), FL400, SELCAL check AB-CD, affirmative CPDLC, over.

---------------------------------------------------

Of course we have already logged on to CPDLC 15-45 minutes prior to the FIR boundary and should have the next controlling agency showing as the active center roughly 30NM prior to the FIR boundary.

Thanks for any clarification you can provide.

[RandomPerson8008]

Great, thanks for that information! I appreciate your help. It makes sense that you can omit your position and altitude in the initial call up since they have you on ADS, but I wasn't sure. In my use of it so far, it has been a big help, particularly in the singapore FIR whre there's a compulsory reporting point every 100NM and you're on the same HF frequency as 2 or 3 ATC agencies and a few dozen a/c! whew! :ok:

-RP8

[Captain Dart]

The Australians will also require you to manually send a position report at each FIR boundary, including the 'internal' one between Brisbane and Melbourne.

They are like my wife if you don't send it within one nanosecond of processing the FIR waypoint; that 'request position report' message comes up in a flash! (usually 'crossing' with the one you've just sent'...)

Sorry. You've just got me started on anal Australian ATC...

[80-87]

If you log on to CPDLC/ADS 15 mins prior to the boundary and still in voice contact, I make a voice position report and include the words 'CPDLC Established'. There is no right or wrong way to do it.

At the boundary, make a manual CPDL report. Check and make sure that you have an ADS connection. If it is working correctly, you won't have to provide another manual report.

And its true...the Aussies are a touchy lot, for whatever reason. If operating in Oakland area, it is straight forward. With the advent of auto reporting, especially in the OAK FIR, it virtually leaves a pilot with nothing to do but monitor the airplane. Occasionally on the B777, the 'Pilot Response' used to come up on EICAS because everything was working so smoothly.

[ghw78]

All the proceedures for the 41 different Air Traffic Agencies using ADS CPDLC and FMS WPR are contained in the ICAO GOLD (Global Operational Data Link Document. The first edition of this was produced in July 2010.

There are differing requirements for operating in different airspace

for example on the North Atlantic, the term CPDLC is attached to the callsign,

In the US in Oakland Oceanic Airspace (Pacific Ocean regions) the term CPDLC is used in the initial voice call amongst with other data such as the Tail Number, Destination, Aircraft type and FIR Boundary Position.

In Japan (Fukuoka Oceanic) the words are " we have CPDLC Connection"

The document is a fairly hefty one at 320 pages and a PDF file runs to 8.5 Mb.

Superb system provided your airline uses it correctly and does the correct thing for the airspace that you are in. Beats voice reporting and HF anyday.

[The Dominican]

The Air Traffic Control section on your Jeppesen has the information on CPDLC/ADS procedures for each air space including position report requirements. It will say something along the lines of "position reports are required regardless of ADS connection"(press send after passing the fix) or "position reports will be made primarily trough ADS" (don't send after passing the fix)

There are a few things to remember while operating with CPDLC, make your weather deviation requests early because sometimes it takes a little while for them to get back to you and make requests that won't need to be amended (if you think you need 10 miles right of track, request 15)

Don't amend the flight plan on the legs page, some folks like to place the boundaries for example for reference but this will send an ADS position report at that modified position to ATC (wether you send it or not) most controllers don't say anything but sometimes they do send a request for you to confirm your position just to make a point.

[RandomPerson8008]

Okay, I've had a few more months of using CPDLC and the advice given here has been helpful, I even downloaded the "ICAO GOLD" and have been using it as a reference.

However, I do still have one question regarding the following scenario on page 303 of the GOLD:


E.2.1.1.5
If the flight will exit the CTA into continental (domestic) airspace, on initial contact with the CTA, the flight crew should:
a) not include a position report;
b) use the appropriate data link term after the aircraft call sign (see paragraph E.2.1.1.3);
c) state the track letter if operating on the organized track system;
d) state the last two fixes in the cleared route of flight if operating outside the organized track system; and
e) request the SELCAL check.

In regard to option d), does this mean you should state the last two fixes you have passed or the last two fixes on your route of flight within the FIR?

For instance, let's say you're on a random route and have just passed 5550N followed by 5840N. Would your call to shanwick go like this?

Shanwick Radio, BigJet 1234 on 5567.

Bigjet 1234, Shanwick, go ahead.

Shanwick Radio, Bigjet 1234 C-P-D-L-C, 55N50W, 58N40W, REQUEST SELCAL CHECK ABCD.
---------------------------------------------------------

Also, in reference to the chart describing each ATS's capabilities beginning on page 293: Is there currently any FIR on the planet which is requiring a manual position report at EVERY charted reporting point other than Ujung Pandag and Colombo? Is it safe to say that outside of these FIR's, the only time a manual position report would be required is at the FIR boundary to verify ADS connection or unless specifically requested by the ATSU?

[PIGDOG]

As one of the Shanwick voices, can I just say that on first contact a datalink enabled flight need only give us its 1) callsign 2) CPDLC, ADS or FMC 3) next oceanic/FIR or exit point.

Once we have your callsign we know exactly what your selcall code is (and any relevant position reports). So saying it takes up airtime needlessly. (In the rare instance where your flightplan hasn't automatically gone into our system we can always ask you for your selcall code.)

You don't need to give your position or your routing. The track letter (c) or the last two fixes (d) are only to let us know where you're going next, so we can give you the appropriate frequencies.

"Shanwick, Speedbird 245. CPDLC. Santa Maria next."
- it's concise, and it tells us exactly what we need.

"Shanwick, Speedbird 293 at Dogal, flight level 360 estimating 54 north 20 west at 1915 and gander is next. CPDLC. Alpha Hotel Delta Sierra"
- a lot longer and even though the information we need is in there, so is a lot that we don't need.

I hope this helps.


PS to answer Random's question directly, d) is talking about the last two points in your clearance. These are named pairs like Dogal Bexet, Etiki Reghi, Omoko Gunso, etc. and it would normally be worded like this

"Shanwick, Air France 007, CPDLC exiting Dinim Elsox"

[CONF iture]

Helps a lot PIGDOG.
Nice to get the info direct from the source.
I take good note.

[nitpicker330]

Captain Dart.........The "request position report" message you get after entering the YMMM or YBBB FIR is automatically generated after a short period of not receiving one from you. All done by the system and not the result of a anal controller!!

[B737NG]

If it is set by default in the system it is still a unique one in the YMMM / YBBB Airspace. Even the Japanese changed it a while back that you have to send the position on each reporting point. They are now satiesfied with the ADS in automatic mode. Maybe Aussie technology is not that advanced???

Captain Dart´s opinion about the downunder system still stands.

Fly safe and land happy

NG

[RandomPerson8008]

Thank you very much, PIGDOG. It's good to know that I can eliminate the SELCAL identifier, at least with Shanwick and Gander.

I must say I do enjoy the level of service provided in the north atlantic compared to, say, NOPAC (no offense to any Oakland/SFO ATC reading this). I cross the Pacific much more regularly than the Atlantic and probably would not omit the selcal over the Pacific; they still ask for things like aircraft registration, departure and destination, etc on initial call-up! It's also difficult to get reliable handoffs to HF in the NOPAC, at least in my experience.

Anyway, thanks again, you've been a big help; maybe next time I will actually sound like I know what I'm doing when I call up on the HF.

[nitpicker330]

On my last visit to YMML ATC I asked why do we always get "request position report" 30 seconds after entering the FIR? The answer was that it was automatically sent by the computer if it hadn't yet received one from you. :ok:

So now I send one a few miles before the waypoint and that solved that. :ok: