ideoplastic

LNAV not tracking

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Keep having an issue with the aircraft not tracking the magenta line of the flight plan.

Veers off to the right and to the left of the track all the time and never manages to settle on it.

 

AP/LNAV/VNAV & Flight Director all active. Track Up ON

No strong winds aloft present.

CTL Input with AP On - Disabled

When issue occurs  The FD cross bars become a single horizontal bar.

Sometimes aircraft goes completely off track.

Using the yoke and correcting manually will allow me to go back on track but on release behaviour returns as before, surprising considering CTL Input with AP On - Disabled

Switching to heading mode doesn't work either.

Haven't found any posts concerning this issue. Could this mean a reinstall of the Aircraft is required? Any feedback much appreciated.

Thanks 

 

 

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Hi,

Usually the FD vertical bar disappearing indicates that the roll mode becomes invalid for some reason. This is confirmed by the roll mode indication on the FMA being struck through in yellow.

Can you confirm this is what you see when the aircraft starts zigzagging?

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I had got the issue several time but only with the pitch mode when trying to engage the AP with the aircraft out of trim and the yoke not at neutral.

Maybe you can check that you the aileron and rudder trims are at zero and you don't have an axis or buttons of your harware interferring with them.

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5 hours ago, ideoplastic said:

Keep having an issue with the aircraft not tracking the magenta line of the flight plan.

Veers off to the right and to the left of the track all the time and never manages to settle on it.

What weather program are you using and what is the turbulence setting there?

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I am using Active Sky for P3D v4 and Max wind turbulence is 100 and turbulence effect scale is 30. This rolling and off track occurred with very light winds.

 

thanks

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11 minutes ago, ideoplastic said:

I am using Active Sky for P3D v4 and Max wind turbulence is 100 and turbulence effect scale is 30. This rolling and off track occurred with very light winds

Set both to about 25%. Guaranteed the max wind turb is causing it. These weather programs are great, but 100% = realistic is not accurate. They're literally pummeling the plane with unrealistic forces. We program the plane to behave realistically, so it must be given realistic values.

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11 minutes ago, ideoplastic said:

After changing the settings didn't have anymore issues.

Thanks you Kyle.

Glad to hear it. You're welcome!

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Unfortunately I have to revive this thread as the problem continues to occur even after changing all the items described earlier in this post and after reinstalling using the repair function with the latest installer on PMDG site. I have uploaded to youtube a small video to illustrate. The aircraft will track perfectly and suddenly will roll right/left and then go off track. This does not happen with either the 777 or the 737. Something else of interest is that moving the yoke (ailerons) allows me to turn aircraft even though the control is disabled in FMC.

https://www.youtube.com/watch?v=M1dIj-smQso&feature=youtu.be

regards

Please disregard this message, a friend who is also a simmer and like me uses Spad.next for the Saitek peripherals told me he had similar issue with a profile that was created incorrectly, I have since changed to a different profile and the LNAV track is solid as a rock. As you can all imagine I am rather relieved as this has been driving me insane for a while.

bests

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