aircraft deviates after 4 or 5 minutes from the GPS course

[henrimarch]

I have followed the training tutorial but after passing the DSD VOR the plane starts slowly to deviate from course. This is under Windows, under OSX the plane stays on course.

But I must mention that the windows machine has more USB hardware, i.e. saitek panels and such, also more plugins are loaded.

The course information is correct and doesn't change but what is changing is the middle HSI bar in the GPS mode. When I switch to HDG and alter to the right course this bar is aligning itself, but as soon as I switch back to NAV mode the deviation begins and sometimes this bar is changing to the other side as does the plane.

Is there something in particular that I can begin to exclude to see what's wrong.

 

Thanks Piet.

[JGregory]

I sounds like you've answered your own question… "This is under Windows, under OSX the plane stays on course.

But I must mention that the windows machine has more USB hardware, i.e. saitek panels and such, also more plugins are loaded."  You may have an issue where your hardware is overriding or interfering with the autopilot

 

Does the AFCS Status Box show "GPS" in green when this deviation occurs?

[henrimarch]

Yes the AFCS box does show green GPS letters when deviation occurs, but thanks for your answer, I shall disable the hardware and begin testing without it.

But I would miss them if this would be the problem.

Edited February 19, 2014 by henrimarch

[henrimarch]

Well it turned out it's not the hardware with the plugins. I saw the other thread about this and read it was solved with version 1.5.1 but I have the same symptoms at least under Windows 64 bits, X-plane 10.25.

I read the workaround about save the flight plan and then load it again. I found another way, using the FMC programmer plugin, if I create a flight with this plugin all is well, the plane stays on course.

[JGregory]

Well it turned out it's not the hardware with the plugins. I saw the other thread about this and read it was solved with version 1.5.1 but I have the same symptoms at least under Windows 64 bits, X-plane 10.25.

I read the workaround about save the flight plan and then load it again. I found another way, using the FMC programmer plugin, if I create a flight with this plugin all is well, the plane stays on course.

The issue in the other thread was occurring on Windows AND Mac.  Your problem sounds like something different, although I don't know what.  No one has reported this problem, especially since the 1.5.1 update.  If you can send me the .fms file(s) ( both the one created by the Corvalis and the one created by the FMC programmer) I will take a look at them.