Need help with interpretation of logs of strange hexacopter behavior

🧪 Flight Testing & Log Analysis
1

Hi,
I was just flying my hexacopter and after initial rising to about 100m it was hovering there. About some 10s of seconds later, it started to fly with high-speed away. It turned around and flew above me in the opposite direction, again with high-speed. In QGC i saw where it was and i switched to RTL (geofencing - 200m should have had done that already). But instead of slowing down and landing it flew crazy around. After it came back, I disabled all motors by hitting emergency off button. The drone dropped out of the sky. I found it. One of the F550 arms were broken.
Broke it in mid-flight? Was that the problem? GPS-Tower was also broken two times, but that was the result of the impact.

How high was it when I stopped the motors?

Logs are here: http://logs.uaventure.com/view/2v43qn7Ri6gANZ9dcX4n47

My configuration: F550, Pixracer, PX4-Version: 1.4.1dev

Thanks for your help!

2

Sorry to hear about your crash.

Initial assessment looks like a mechanical failure. At the time where it stops tracking the position correctly (at 04:52 of the full hour, 20:04:52 in log muncher) I can see severe vibration starting.

I can also see the motors assuming a significant spread. The system also knew it was off-course but couldn’t correct it. That would be explainable by a mechanical failure that misaligned the motor body frame with the sensor body frame.

A broken off GPS mast would do that for example. Or a broken off motor mount. Or a broken off autopilot. It was probably not a complete motor failure since I don’t see any of the channels peaking. So I would right now speculate it was the GPS or autopilot which came loose.