CPDLC and ADS question

[WallyBallbearing]

Hi Everyone:

I'm on a 747-400 and have been using CPDLC for about 5 years now. With my previous company, while flying the NOPAC we would modify the POS Report page to reflect the first two mandatory reporting points then the next point. On the PACOTS route we did no modification(All Mandatory Lat and Long) and in the Oakland FIR we did not send any report (except the first LAT/LONG) because of the ADS system.

I know in with ADS A (aka "C") the reports are initiated by the Pilot via the ACARS/FANS 1/A system manually (Pilot presses the button). I know in ADS type B the positions are sent(or Taken) every 15 min or as the "Contract" values are set.

My question is: Is the reason we have to send the position report in Tokyo FIR and the Nopac (with Modification) and not in Oakland FIR because of the type of ADS system? I'm looked on the web and through various manuals and can't find it.

I hope this is not too stupid of a question.

Any thing on this would be helpful. Any info from an Oakland Center guy would be awesome.

Thanks,

Wally

[ttakne]

Howdy Wally,
Sorry I'm not an Oakland guy (actually I'm quite happy about that as our Gov Palin is a lot cuter than their Governator Arnold) but being an Anchorage Center oceanic controller maybe I can help. Anchorage, Oakland and New York Centers have within the last two years been operational with a new oceanic control platform called ATOP which is an adaptation of Airways New Zealand's Ocean-21 platform. Basic separation in oceanic airspace is 1000 ft vertical, 50 NM lateral or 10 minutes in trail (about 80 NM) for same speed or faster in front. With properly equipped ADS aircraft separation can be reduced to 50 NM in trail, same speed, provided that contract-timed ADS reports are received. Oakland and Anchorage both have domestic and oceanic nonradar airspace in which different separation standards apply. I'll talk to the Oakland guys on the landline tomorrow and ask your specific question and, since further info probably won't interest the casual PPRUNER, I'll try and PM you manana. At Nippi squawk 2000. Report Nippi to Tokyo HF. Gooday and have a nice flight, TT

[oz in dxb]

ADS C is ADS contract, which in some FIRs requires you to advise ATC that they now have controlling authority. This is done by sending a position report at the FIR boundary.
Mainly seen in Brisbane, Melbourne and Auckland FIRs.

Oz

[WallyBallbearing]

Thanks for the info guys.

I guess what I'm saying is:

In the Oakland FIR if the Pilot is logged on to cpdlc, he does no further action in the cockpit as far as far as pushing the "send" button for a position report, its automatic. However, In the Tokyo FIR (Pacots and nopac), the pilot needs to physically push "send" button.

I'm guessing because of the different types of ads systems between Oakland and Tokyo, but I don't know.

I need a beer.

Cheers

[ollie_a]

I think you may have some of the terminology confused, but despite that my guess would be that you are pretty much correct.

First, ADS-B is not used in the oceanic environment; it's something completely different.

The two types of ACARS-based communications with ATC are CPDLC and ADS-C.

CPLDC is the one where you can send manual position reports using the send button, along with other control messages e.g. requesting a different level.

ADS-C you as the pilot pretty much have no control over, ATC set the contract reporting rate and position reports are sent automatically.

I'm not familiar with either of the FIRs in question but it sounds like Oakland use CPDLC and ADS-C but maybe Tokyo only use CPDLC.

[rab-k]

Sounds like ollie_a hit the nail on the head.

Here in the Shanwick OCA (http://en.wikipedia.org/wiki/Shanwick) we use ADS-C and also CPDLC, but I understand any distinction between the systems is not obvious for those looking at the FMC display.

With some carriers, we'll often see an ADS-C position report come down, shortly followed by a crew input CPDLC position report, which needless to say isn't required. (This CPDLC report can even be scrambled by our own kit so as to make it unusable by the controller; the LAT/LONG appearing as XXXX thereby forcing us to work from HF voice or ADS-C reports only). Those reports input manually by the crew and downlinked in the CPDLC format are therefore not used by EGGX.

We also have the ability with ADS to 'Demand' a report, in addition to those for significant points already set up in the contract. (This has on occasion caught out crews who don't realise that even in mid-Ocean big-brother may be watching :E). Emergency settings, if selected, can also increase the frequency of the contract - useful for turn-back/diversion situations.

Sounds very much as though the different procedures, as ollie_a suggests, is due to differences in both the FANS systems in place and the operating techniques on the part of ATC providers concerned.