Fly-By-Wire A is not Working

I have recently bought an ardupilotMega kit. Although it is said that it's a plug-and-play autopikot sestem, I want to say that it is not the case at all. The last rediculus problem I have had was that FBW A doesn't work. FBW B works fine but A doesn't.even the stabilization doesn't work. I really don't know why. I have done everything (trying the new code, changing batteries, whatever), but couldn't get it fixed. Can anyone help?

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  • Hi people , I have a Rx/Tx spectrum dx6i, and my probem is whenever I switch to either FBWA, FBWB or stabilization mode or any other flying mode the throttle fully get closed. And when I switch it back to manual with (gear switch) the throttle goes back to normal state where the throttle stick was left. 


    The gear and flap switches gives me two choice of mode but either I switch to any mode the throttle goes off,


    I was lucky yesterday my friend was able to land the aircraft without engine. since aspiratory egine would not start again during the flight once they go off.

    any Idea

    any idea  ??  


    • This thread is from 2011.

      Check your min and max throttle settings, as well as your radio calibration.

      • Ok I just change the throttle parameters, things got much better, now when I switch to autopilot board no matter any mode the throttle cuts off only about 15%.

        Another thing which I did and it might was the reason was I change the regulator voltage output from  6v to 5v. just brought it back to normal. Maybe the throttle servo had sort of malfunction when It reaches 6v. because I measure the APM output 3 and I did not see any voltage drop there. So it was on the servo side not the APM. Anyway thanks for the help Jonathan    

  • Thank you very much Jonathan, you was rigth!

    Planner accepts to chose:

    mode 1 = selecting manual

    mode 5 = selecting stabilize

    mode 6 = selecting FBW-A


    With what you said I reversed my Ch5 and Ch6 channel and selected in this way:


    mode 1 = selecting FBW-A

    mode 4 = selecting stabilize

    mode 6 = selecting manual


    Now it is working as expected in all modes. 


    I checked the APM documentation regarding "First-time APM Setup". This is in section 3): "... Note that Flight Mode 6 cannot be changed from Manual..". However,  Planner allow you the user to select besides the PWM values. I didn't realized about PWM > 1800 to be mandatory associated with Manual so why I selected FBW-A for mode 6 and was the base of the mistake. 

    A suggestion would be the Planner mode 6 to not present a dropdown control and always be manual. 


    kind regards,


  • Hi, I think there are some confusions on this thread. But in fact I having a problem with my system. Please see the last tests performed:

    1) APM in manual mode.

    2) I then enter on Planner and Send the "set FBW-A" mode.

    3) APM entered FBW-A mode. I take the airplane in my hands and move it, bank it. The aileron, rudder and elevon moved as I was expecting without any radio inout.

    4) on Planner I send "set manual" mode. Manual restored in APM.

    5) I put the radio switch in FBW-A position. Planner present the current FBW-A mode status. I move and bank the plane without radio input. No aileron, elevator and rudder responses.


    So, my understanding is that there is a problem, right?


    What is to be the expected aileron,rudder and elevator actions if bank the airplane in FBW-A when activated using the Radio and when activated by through Planner?

  • This problem is happening with my 2 APM too. One was bough inmay and another in august this year. I'm running last APM program. Tried by loading from Planner 1. 68 as well compiling and loading through Arduino. The behaviour is the same:

    - stabilization mode: APM apply the corrections as expected. Using TX sticks works too.

    - FBW A: APM works  like manual.

    The current mode is presented in the Planner according TX switch as expected.

    It is only possible to put APM in FBW A if I use the Planner FBW A combo selection and press the button to send to the APM. I will not fly until all modes are working properly.

    TX/RX/XBee = Spektrum DX6i/AR6200/Xbee 900Mhz (but the problem happens even with USB cable).

    Please, could you provide some directions on what to test/look to try to find the problem?

  • Are you certain you're in FBW A?

    Connect to the mission planner in flight mode, your mode is displayed in the bottom right hand corner of the attitude indicator. Make sure that you're really switching to FBW A and not manual.

    If you don't have an airspeed indicator, FBW B just sets the mode to FBW A, as an airspeed sensor is required for FBW B.

  • here are the log and the paramlist files


    11-09-14 08-55-10.tlog

  • Moderator
    I'm kind of curious, where did you buy the plug and play autopilot?
This reply was deleted.


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