Crash when autotune

I tested autotune on my copter and it suddenly fell into the ground. Before crash, I had done about 100 flights and after crash after replacing the broken arm to the engine, making new flights without any problems. Can any of you look at the attachment log?

Regards YB00000116.BIN (779.9 KB)

Hey looks like a failure of your no.3 motor/esc. If it’s suddenly turned up in an autotune then possibly a desync - do you have large props/motors?

You have your autotune parameters at max??
What size copter?
If it’s over powered you could have just had the settings too high.
As @fnoop suggested, it could have been a desynchronising.

Hi fnoop

920 kv motors and 945 propps

Hi Mike

500 mm copter with 945 propps and 920 kv motors.
Total weight of 1600 gram