Weird Crash after updating to 3.5 RC7

Just on my second short flight after updating to 3.5 RC7 (from 3.4.6). First one was three minutes of hovering. Uneventful. About 30 seconds into the second flight, I had just switched into Loiter and was hover when my Quad flipped over and crashed headfirst into the ground. Looking thru the log I’m not sure which of the “spikes” are from the crash and which one was the cause everything seems to happen at about 15.2 on the timeline. If someone with a little more experience at reading logs could take a look and help me get to the bottom of what cause is, it would be appreciated. Under POWR there is a large dip in VSERVO (but I’m not really sure what that means.)

2017-06-09 16-41-26.bin (611.0 KB)

It looks like a mechanical failure on motor #1. Either the motor, ESC, or propeller. From these two graphs you can see the actual pitch/roll deviated sharply from desired. And that the #1 motor output was the first to go to full power as it tried in vien to compensate.

Ah ha. That makes sense. The coincidence of it happening right after the update to 3.5 RC7 was what was throwing me off. I couldn’t figure out why such a late release candidate could still have a problem like this. A mechanical failure make more sense.

It all happened really fast, but I believe it flipped over to the left. Wouldn’t a motor 1 failure cause a flip to the right (looking at it from behind the quad)? It a X quad. Does one of the graphs show what direction it flipped?