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CPDLC losing link.

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Old 4th Jan 2016, 15:06
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CPDLC losing link.

Hello.

We used our new CPDLC for the first time the other day (GLEX) in the Eastern Pacific Hawaii Tracks and on Dec 26 we had a good link 90% of the time but made one report on HF. On the return flight however, Jan 2, we logged on fine in PHKO but once airborne soon lost the link, restablished briefly a time or two, but for nearly the entire flight to California the link was lost with a NO COMM message.

New to the system and not sure how reliable it SHOULD be. Anyone with advice or a clue to why so unreliable? I know there was a strong solar storm on Dec 31, could this cause a problem 2 days later?

Thanks.
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Old 4th Jan 2016, 15:33
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It should be boringly reliable. One check in position report to KZAZ and then 3-4 hours later a message to contact HCF or Oakland or LA. Going south from HNL it seems like it will loose coverage for about 5-10 minutes a couple hours out but after that works fine.
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Old 4th Jan 2016, 16:34
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It is very reliable.

We lose comms about 5 or 6 times during a 14 hour Pacific flight for 20 seconds at a time as the system changes satellites. That is using KSAK and NZZO.

There was an issue with a satellite fault a few months ago in the North Atlantic that cause a loss of comms in a small patch of airspace.

Last edited by c100driver; 4th Jan 2016 at 16:36. Reason: spealing
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Old 4th Jan 2016, 16:41
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For comparison, on the A330 I lost the link maybe twice per year, over many years. At least two Atlantic crossings per week...
So system-wise it can be very reliable.
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Old 4th Jan 2016, 17:17
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Who is your service provider? Maybe they can shed some light on this as it's always been very reliable. Make sure all your subscription parameters are correct. Is this a Collins or Honeywell system?
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Old 4th Jan 2016, 17:22
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What flavour of CPDLC are you using? HFDL, SATCOM (FANS) or VDL?
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Old 4th Jan 2016, 19:18
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We have a Honeywell system installed and use SATCOM Direct as our provider.
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Old 4th Jan 2016, 20:20
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I know of an operator that recently had some issues with SatCom Direct as they were had his system set up for a Honeywell when in fact it had a Collins system. Just a wild guess but these guys should know the difference.


I don't believe VDL is available anywhere in the CEP and HF is pretty rare. HAL was using it for awhile in their 767 fleet.


Let us know what you find out.
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Old 5th Jan 2016, 08:42
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No Comms...

I've transited NOPAC/SOPAC/with CPDLC nearly since its inception (B777). Sounds like it might be a satellite reception problem alright.

As 'Marker IB said:
It should be boringly reliable.
With the advent of automatic position reporting features, I can barely remember how to make a position report on HF anymore.
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Old 5th Jan 2016, 10:21
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CPDLC and ADS-C (position reporting) are two different animals other than the fact that they both use the satellite for connectivity.


The poster did not mention weather he was using Inmarsat or Iridium for his connections?
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