Crash on autotune copter 3.3.2, 12 kg quad with U8 on 28" props


I have a quad with U8 motors and 28" props, ESC’s are T60 as recommended by the motor manufacturer, PX4 and Copter 3.3.2 are in use. TOW is 12 kg.

I have read about the difficulties people are having with autotune and this size quads & high pole count motors. I have carefully tried to tune the PID:s myself. As a result the ship flies quite well in stabilize and loiter modes but I still figured autotune would be wise to do.

Well… the start of the autotune went well, but on the 3rd or 4th twitch the copter started to overshoot and came down hard.

Attached is the logfile of the flight. I would very much appreciate if someone still would care to take a look and and point me to right direction…

Thank You for any input!

The log is here: