APM 2.5 Plane no servo control in STAB or FBW mode

Hi, I have just bought an APM 2.5. and installed the latest (3.0.3) plane firmware.
I would like to use it on my flying wing with 9XR radio and Frsky D8R-II Plus receiver.
I followed the user manual to calibrate radio and set up elevon mixing in APM Planner.

Everything works fine in manual mode but when I change to STAB, FBWA or Cruise mode I don't have control over the servos. I could make one servo to move about 2 millimetres but that's it the other one didn't move at all.

In STAB mode if I tilt the plane to the right the right elevon goes up (it should be move to the opposite direction to compensate)

Any idea what can be the problem?

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  • Thanks Sebastian,

    I'll try that today evening, hope it'll work for me too.


  • Does anybody know the solution to this problem?

    • I was able to fix this issue on my APM by resetting to factory defaults. To do that, go to the terminal tab. A few menu options should pop up (it will look similar to if you were using command prompt) so then type "setup" (hit enter), "reset" (hit enter), "y" (hit enter). Your APM should be back to factory defaults now and if you go straight to testing out any of the flight modes, the servos should be fully functional. You may still need to change the servo reversing parameters though. 

    • I did the reset.

      After it said "Factory reset completed. Please reset to continue" or something similar I pushed the reset button on APM and lot of different characters started to run in the Terminal window. I was waiting for 15 mins but they were still running all over the screen.

      Is this normal?

    • Yes, after it says that the APM has been reset to factory defaults you can use it like normal. No need to press the reset button, just go to your flight modes and test them out :)

    • Yes. It seems that it's working properly now. I have servo control in all the other modes too.

      Thanks Sebastian!

  • I'm back again :)

    Wasn't able to fix the problem. So in manual  mode still working fine don't need any servo reversing.

    If I switch to any other mode (for example FBWA) the servos stop moving. On the calibration screen the bars are moving right but no actual servo movement. It seems I have the right input from the receiver but APM doesn't give the output to the servos.

    • I'm having the same issue

  • Try Radio calibration. I recommend you to spend some time reading the instructions. It will answer all your questions.

    • I'll do that.


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