View Full Version : use of CPDLC

7th Apr 2002, 16:34
Hi All,

I just wanted to pick a few brains about the use of CPDLC. what authorities are needed for use of CPDLC? and what is the procesure for that?or where can i get the procesure? and is there any defects of CPDLC?
thanks a lot, guys!:)

7th Apr 2002, 18:55
Sorry to sound thick, but what the hell is CPDLC?

Or should I know?


7th Apr 2002, 19:40
Speedbird 252,

CPDLC = Controller/Pilot DataLink Communications.

Wingtip 77,

This has all yet to be decided...... We're talking years away from final definition.

7th Apr 2002, 22:31
Wing Tip77 - CPDLC has been in use over the Pacific for some considerable time, it is also available in Australian oceanic airspace, (but not widely used).
It requires that the aircraft and the ground stations are properly equipped and that the airspace is designated as available for CPDLC use. Soon to be coming to the North Atlantic I believe.

Four Seven Eleven
7th Apr 2002, 22:46

CPDLC is used in Australia, as GK mentioned above. It is currently used mainly in Oceanic areas, where VHF coverage is limited or non-existent.

The major advantages so far:

1. Eliminates the need for HF comms (and in Australia at least, these comms are done by a third party HF operator, not the ATC)

2. Both ATC and pilot have a text record of the communication.

3. Apart from 'free text/ free format' messages, most messages require some sort of logical response, and cannot be 'closed' until this has been done. For example, if an aircraft requests a level change, ATC must respond using a number of preformatted responses, ranging from 'unable' to 'climb/descend' to FLxxx'.

4. As most messages are pre-formatted, language difficulties largely disappear.

5. Most CPDLC equipped aircraft are also ADS equipped. Most routine position reports are done via ADS.

A limited trial of CPDLC in areas of VHF coverage is likely to take place later this year, and use of CPDLC is likely to spread to more and more of Australia.

The major disadvantages so far:

1. Because of the reduced voice communication, other pilots are less likely to be aware of traffic in their vicinity.

2. There have been instances (at least one) where the wrong aircraft has been given the instruction. In the case I am thinking about (and don't quote me on the facts) I believe that 'authority' over a CPDLC connection was not properly transferred between two centres. Some time later, the controller intended to give a level change to an aircraft with a similar callsign and inadvertently gave it to the aircraft a few hundred miles away in the next centre's airspace.

3. Pilots are still required to call on the appropriate VHF frequency, even if CPDLC is used.

Overall, it has been successful. It is a bit like the difference between e-mail and talking on the telephone.

Draculas Teabag
8th Apr 2002, 08:27
CPDLC is used in Australian, Fiji, NZ, Tahiti and Oakland Oceanic FIRs. It is also used on the Sydney - Jo-burg run.

I'm not sure what 'trial' you are talking about, CPDLC is always used (as far as I'm aware) in the YMMM/YBBB (melbourne/brisbane) FIRs when the aircraft is so equipped.

So far the only ones I have seen accept ADS are the Aussies, NZ and Jo-burg i.e. the others require you to push the "position report" button every so often (a major imposition).

To counter the problem of an aircraft getting a message intended for another aircraft, it is now a requirement to send a position report (even when ADS'ing) whenever you logon to a new center.

Jakarta (WIIZ/WIII) supposedly have datalink but I have never had the logon accepted.

HF comms in Australia are done by Flightwatch which I guess isn't really ATC, ATS I think they call it. HF in Oakland Oceanic is handled by San Francisco ARINC, a private company.


14th Apr 2002, 04:17
thanks a lot to all! especially to Four Seven Eleven and Draculas Teabag!
some of my workmates did use CPDLC on pacific ocean route, but then we were informed that wasn`t authorised, because we are not trained to do that. but recentlly, on the australian route, we are asked to use CPDLC, and lots of us are using. so i am really wondering if we need authority and training or not!

14th Apr 2002, 04:31
In addition to all the above, Kuala Lumpar, Yangoon and Calcutta all have CPDLC, it has been trialed by Maastrict as well.

On the North Atlantic Gander have been using ADS for quite some time, not sure but I think Shanwick also.

Frequent SLF
17th Apr 2002, 14:21
CPDLC is also being used in Anchorage, Tokyo and Tahiti FIRs, and on L888, the Western China route which skirts around the Tibetan plateau to give a more direct route from the Far East to Europe, avoiding the joys of the "South-of-Himalayas" airspace. QANTAS may still be the only airline using L888.

NAT CPDLC trials are planned for this year to supplement the ADS waypoint position reporting operational trials currently running in Gander, Shanwick, Reykjavik and Santa Maria FIRs.

FANS-1 or FANS-A is required for CPDLC; satcom is also useful if you want datalink comms in oceanic airspace :D

Freq SLF

17th Apr 2002, 15:11
Has anybody use CPDLC_ADS in Chennai? if not somebody knows when it is going to be up and running.

Four Seven Eleven
17th Apr 2002, 15:20
Draculas Teabag
I'm not sure what 'trial' you are talking about, CPDLC is always used (as far as I'm aware) in the YMMM/YBBB (melbourne/brisbane) FIRs when the aircraft is so equipped.

True. CPDLC equipped aircraft generally are logged on, but VHF remains the primary communication method when in coverage. For instance, if you downlink a CPDLC request for level change when in VHF coverage, you are most likely to get an 'UNABLE' response (to close the message) and then a response via VHF.

The 'trial' is to determine the benefits of making CPDLC the primary communication method (for appropriately equipped aircraft) even in VHF coverage.

Sorry I can't give you any info on whether or not you require training. It seems you would (we do), as there are some 'traps' if you don't know what you are expecting.

18th Apr 2002, 04:13
thank you very much, 4711 !

4th May 2002, 06:20
could anyone tell me please: who are those airlines using CPDLC on the world now?

4th May 2002, 12:21
for more info on CPDLC, goto...


WRT, who uses CPDLC currently. I believe all B777 were delivered with FAN1A capability. Many 747 and airbues are also being retrofitted with such capabilities. I know MH, SQ, QF uses CPDLC regularly.


Draculas Teabag
6th May 2002, 05:38
For those who fly over Indian airspace I noticed that our logon to Chennai (VOMM) worked for the first time the other day. And they have ADS! :)

It is not being used as primary means of communications so you still have to to use HF for pos reports. There is a notam regarding use.