There are good days, there are bad days and there are days beyond bad days


ArduCopter V3.2.1 (36b405fb)

Great day for flying, wind 1-2m/s, sunny. The aircraft was flying great until I started coming back to land. It suddenly started yawing (to the right if I remember correctly), then stopped, then yaw again, stopped and yaw again until it hit a tree. I had no control when it was yawing but I was able to control it when it was not yawing (between the yawing "cycles"). It felt like someone was pushing YAW right stick, it did not feel like it was correcting for a motor/ESC etc error. I would also like to point out that all motors were working when it was in the air. I also included a log if someone is able to point out what caused this not so cheap crash. I was not able to determine the error by looking the log file(s). 

PS. There was a truck crane operator near me with a crane remote if this is relevant in any way. The crane remote should work @ 433Mhz but I am not sure.


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  • It seems obvious from the log that there was a mechanical failure on one of the motors.

    • RCOU data for output channel 6 shows zero output to channel 6 through the whole flight

      • However - there are values in the RAW data for RCOU(6) - might be a MP graph fault.

        • Looking further I can see the log file is corrupt - please post the original BIN file.

          • Thanks for the replies, Mark Slater . Here is the .bin file. 


  • Hey MR, this looks suspiciously similar to what happened to my friend's quad.

    Looking at the logs, I see RCIN C4 centered but at the same time under ATT the DesYaw gets the quad spinning.

    The same thing happened in our case, with no control when it was spinning.

    Maybe someone can chime in where is this DesYaw coming from?

  • Moderator

    Ning won't let me download the .rar maybe zip the logs

  • If an arm rotated, like in the picture. That would give a result as described, and require lots of skill to fly.
    • Thanks for the reply, Andre K. Rotated arm will definitely result in uncontrollable YAW behaviour, but it would not "cycle" like it did in my case - it would be continuous. In addition, since I was not far away from the copter, I can safely say, that all arms were straight before the crash.

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