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Bryn

777 stops tracking LNAV - though LNAV sill on

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Hi,

 

On a few flights recently, the 777 has veered off course and stops tracking LNAV. Here's a map of what happened:

 

Map.jpg

 

And here's the panel view (using my 2d backgorund for a clearer screengrab - though I was in VC during the flight):

 

 

panel.jpg

 

You can see that LNAV is still on, but it's way off course, and just goes slowly back and forth around a south heading.  Any ideas?

 

Bryn.

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Weather problem. You have a +4 temperature at FL320.

It should be more like -44.

 

What weather program do you use? and do you use FSinn?

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TAT is +4, making SAT somewhere around -20 to -30 I think at M0.82.  ISA is about -46 at FL320? So it's warm, but not too warm.  TAT shouldn't be -44 at FL320... that would be crazy cold.

 

I do use FSINN though.  The weather is off, though do you think it interferes in another way?

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One other thing - on both flights where this has happened, the track was switching between just above heading 000 to just below 000 (ie from 007 to 357 and back to 004).

 

Just struck me that that could be some sort of boundary issue.

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Hi

 

Only thing I can see is the RH flight director is off - I do however doubt that has anything to do with it!

 

That does seem to be some distance off course however? (Note I am not suggesting that you have reverted to hdg sel, i.e. fine if you were seeing what would happen!)

 

Regards

 

Carl

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I had a similar issue last night on a flight from VHHH-LFPG. Came home after work to find a zig-zag path (like your picture) and was flying southbound just west of Australia!

 

I'm using the default FSX weather. Nothing else.

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Same problem here, it happened on the last three or four flights.

 

I am using Active Sky Evolution for the weather, think crosswinds could be a reason for this.

 

Enabled the "Smooth wind changes near aircraft" option within FSUIPC (registered version), but the problem still occurs.

 

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I also had this issue recently during flight VHHH-LFPG.  It happened at a waypoint where the T7 should have made a ~90deg

turn.  The T7 exited the route at the PEXUN intersection and wandered off into SE Asia (see attached screen cap of FSC map).

Fortunately when I awoke from my nap I still had enough fuel remaining to get back on course and complete the flight without 

calling for the "tanker" :rolleyes:

Best to all,

Ken

 

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