Hi,
I am writing my bachelors on CPDLC installation. I would like to give it an engineering input, so maybe you have any ideas on what i could change in cpdlc or maybe create some additional system that could be useful and would be working on the side of cpdlc? It could be only theorethical, but should be possible to implement
All ideas are really welcome!
Avionik wrote:
I am writing my bachelors on CPDLC installation. I would like to give it an engineering input, so maybe you have any ideas on what i could change in cpdlc or maybe create some additional system that could be useful and would be working on the side of cpdlc? It could be only theorethical, but should be possible to implement
All ideas are really welcome!
Easy! To produce a cost-effective CPDLC appliance/App/… that can be used in low-end GA. :)
Most ATC has no CPDLC capability, or does it?
Peter wrote:
Most ATC has no CPDLC capability, or does it?
At the moment, large airports (Likes of EGLL, EGKK, EGLC etc) and UIR.
arj1 wrote:
At the moment, large airports (Likes of EGLL, EGKK, EGLC etc) and UIR.
Yep.
Some countries are not equipped, and most unions are absolutely opposed very reluctant to the system. ATC in general probably realise that CPDLC could be the beginning of the end, as most services could be replaced tomorrow by capable computer, at least for the enroute portion of any flight. For me it is unbelievable that in this day and age, we’re still to use vocal communication when flying in the upper FLs, as in RVSM airspace. Nonetheless following more than a century of commercial aviation…
Must be getting really old now since I remember the days when ATC were here to help, and not the opposite like it is today…
Rant over and out 
Dan wrote:
we’re still to use vocal communication when flying in the upper FLs, as in RVSM airspace.
Voice communication has some advantages over texting, still: Most important is the near realtime acknowledgement. After the controller issued a voice message, he will immediately get the ACK from the pilot – and if not can assume the message did not pass through. So the E2E transaction is finalized before the controller turns to the next airplane.
In CPDLC, the controller has multiple messages open and needs to check a bit later if he got an ACK. Obviously yes, this can be solved by technology but it’s always a bit clumsier.
There is this old joke: “Wouldn’t it be great if WhatsApp would offer a functionality to be able to listen to a voice message in real time while the sender records it and answer right away ?1?”
Malibuflyer wrote:
Voice communication has some advantages over texting, still: Most important is the near realtime acknowledgement. After the controller issued a voice message, he will immediately get the ACK from the pilot – and if not can assume the message did not pass through. So the E2E transaction is finalized before the controller turns to the next airplane.
In CPDLC, the controller has multiple messages open and needs to check a bit later if he got an ACK. Obviously yes, this can be solved by technology but it’s always a bit clumsier.
*most of the time.
As I’ve heard from the London Control recordings it is not always the case (“XX turn left 270 break-break YY climb FL320 to avoid break-break ZZ descend now FL280”), but, yes, generaly with voice in most cases you get synchronous, single-threaded, FIFO comms, while in case of CPDLC it is multi-threaded async.
My perception is that SIDs, IAPs are are best flown on voice, while departure clearance and enroute/STAR parts are OK for CPDLC.
I cannot see how a dialogue on avoidance of wx can be done with a keyboard/keypad. Especially single pilot.
Especially if you get some crazy controller like the ones I got a few times, e.g. in the Munich area, refusing wx avoidance and telling me to do a 180 and go back home 
I would also miss the “I am utterly bored with your requests; what do you want now?” voice of the Swiss lady controller a year ago, or the one a few years before that where another pilot, gliding a vast distance away, told another young lady controller that I was lying about the wx, and said it in German so I did not work it out, but of course others later translated it (these made such great videos)
Passing clearances, sure.
Hi @avionik
Since this is more a general aviation forum i don’t know if you will get mich replies from people who actually used the system.
From my experience:
We had a honeywell system installed on the B737 (a few had the boeing system but i never flew with that one)
It takes a lot of button presses to go to the cpdlc menu and read or send a message.
If you get a direct you must use the 2 fmc’s to see if you can accept it (for wx) so you both ar heads down or send a standby message, check, send an able message, receive the clearance, execute the clearance.
These are more problems of the implementation of the system.
Now on the usage:
In France only used for frequency changes
In Italy only used in certain areas so you get a lot of messages “cpdlc not in use” “cpdlc now in use” “cpdlc not in use”
In Germany it is used properly for all clearances but there you have a frequency change every 2-3 minutes so there are also a lot of messages. When you switch the frequency they reply identified and at the same time you get q cpdlc message to climb.
And then in general all the messages “current data authority XXXX” “next data authority XXXX”
It is in general just too much of the 2-tone bell going off that you receive a message.
Let’s say I didn’t mind if the system “wasn’t working”
It might just be the way it is implemented on the 737 and in germany they way the airspace is devided.
I just switched companies and am about to start flying long haul so maybe in a few months i have a different opinion.
I hope this helps you a little bit and otherwise you can also send me a pm for more info
ICAO has the new concept of “Performance Based Communication and Surveillance” (PBCS), which has the same idea as Performance Based Navigation (PBN) – namely that rules, regulations and procedures need not refer a particular technical solution but to the performance of the technology used. While in PBN the performance parameter is (primarily) the navigation accuracy, in PBCS the performance parameter for communication is the time it takes for a message from ATC to reach an aircraft and the aircraft to send back a confirmation of receipt.
So in PBN you may have the performance specification RNP 1 (Required Navigational Performance with 1 NM navigation accuracy), while in PBCS you may have the performance specification RCP 240 (Required Communication Performance with 240 seconds turnaround time).
RCP specifications are currently applied in the North Atlantic airspace where pilots already are not communicating directly with ATC but with a HF ground station acting as a middleman.
