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AFL581

Lnav track not followed on long legs

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Hi everyone,

Yesterday I tried to fly from TNCM St Martin to UUEE Moscow. The majority of the flight is over the North Atlantic.

The Preflight and Departure went fine, but then when starting the oceanic legs between coordinates ( each leg being 300 Nm+) the autopilot just stopped to track the LNAV track.

After 10 minutes of letting it doing it's own things it started to climb and descend and the airplane was completely out of control.

I tried to reload the flight at the last " working " waypoint and used HDG SEL instead of Lnav to see if it made any difference. No issue , it followed the HDG SEL for ever and there was no change in attitude.

 

May it be the S-Turn problem caused by turbulence generation with Active Sky ? If so, what is PMDG policy regarding weather settings ?


So my question is :

Is there any limitation in FSX or the PMDG 777 regarding the maximum lenght of a leg between two waypoints ?
 

 

 

Thank you very much for your time and assistance fellow pilots.


JB

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After 10 minutes of letting it doing it's own things it started to climb and descend and the airplane was completely out of control.

 

Using acceleration?

 

 

 


May it be the S-Turn problem caused by turbulence generation with Active Sky ? If so, what is PMDG policy regarding weather settings ?

 

There are recommendations in the intro manual.

 

 

 


Is there any limitation in FSX or the PMDG 777 regarding the maximum lenght of a leg between two waypoints ?

 

No.

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Hi Kyle,


No, it was rate 1 flying, no acceleration.

I will read the intro manual again, I guess I missed that bit since I had no issue before the SP1.

 

Anyone ever encountered the same ?

By the way, it was the first time I used the FLP datalink upload  after generating it from PFPX, before this I always inserted COROUTE directly.
 

 

Thanks for your time.

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No, it was rate 1 flying, no acceleration.

 

Hmm...sounds more like a weather interaction issue, then.

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Hmm...sounds more like a weather interaction issue, then.

Maybe, I am trying to investigate the " S-Turn " isssue with Active Sky and FSUIPC but it is a rather complex system and determining who send what to FSX and what are the effects is rather difficult.

 

However, the S-Turn issue has been narrowed down to the TURB generated by either FSX / FSUIPC / Active Sky.

 

JB

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