@sashat720 wrote:
Hi all,
I ask for your help figuring out what happened in a plane crash (PX4 with Plane 3.6). I have no airspeed sensor so ARSPD_ENABLE and ARSPD_USE are both set to 0.
My Bix3 (Bixler) took off in Manual and then was flying well in RTL at 100 meters altitude.
I then lifted the flaps completely. The plane, which was still in RTL went into a nose dive. I switched to manual to take over control but I was too late and the plane crashed.
The The flaps are on RC channel 5 with pass-through, so the PX4 doesn't control them. The elevator is on channel 3.
I have analyzed the log file and wasn't able to find the reason for the plane going into the nose dive after lifting up the flaps completely.
I can see in the graph that the flight controller knew that it had a negative pitch (ATT.Pitch) and it tried to achieve a positive pitch (ATT.DesPitch) by outputting elevator "up" of about 1400 on channel 3 output.
Somehow this wasn't enough elevator "up" to bring the attitude back to horizontal? I have to say that the max elevator "up" value is 1100, but I have no idea why the flight computer didn't output the max elevator "up" possible.
I am attaching the log file and also the graph. I trimmed the log file to the essential part so the filesize is low enough to be uploaded here.
Any ideas why this whole crash happened as it did?
2016-07-27 17-45-32___.zip (697.9 KB)
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