Crash, 3.5.3 - X8 configuration

I ask a question for a friend who had a crash.
Crash occurred in autotune when tuning Pitch axis. all the other axis are adjusted correctly. Just before crash the vehicle turned upside down and crash. Looking the log file it looks like GPSglitch on GPS2.
It would be grateful if someone could explain better what the cause of the crash…
Gps_auto_switch= Blend

Configuration X8
Motors kw9
ESC hobbywing 35A /oneshot 125,
Battery gens ace 2x16000
Props - 17”
Pixhawk 2
GPS 1 - M8P
GPS-2- M8N

Log crash

Quoting from http://ardupilot.org/copter/docs/autotune.html

For large copters (with props at least 13inch or 33cm diameter) set the Rate Roll and Pitch filters to 10hz (in Copter-3.3 these are RATE_RLL_FILT_HZ and RATE_PIT_FILT_HZ, in Copter-3.4 they are ATC_RAT_RLL_FILT, ATC_RAT_PIT_FILT)

Had the same happen when I left these at default and tried autotune.

it was set to 10Hz , roll autotune went ok , then after charging batteries tyed to make pith autotune , but it went bad…

on roll autotuning gps_switch was set to 1, and when I went to make pitch autotune, I have set gps_switch on2 (blend ) …

Thank you all for help…

But bad news, today, new crash same in autotune mode …:disappointed_relieved:

Log here,

Looks like a de-synch issue, or loss of thrust on the right rear corner with motors 4 and 7.

Both turn overs had the signature of the PWM signals for those motors saturating high.

The EKF and GPS errors are after the turnover and crash.

do you think it can be related to damping light feature on oneshot esc … it was active

I don’t know enough about oneshot125 to help with that.