I've seen this a few times. Thought I'd put up a log and see if anybody has any ideas. This is usually a catastrophic failure. I lucked out and the airplane recovered.
* Tuffwing UAV Mapper: http://tuffwing.com/products/drone_mapper.html
* Arduplane 3.7.1
* Hobbyking Pixhawk
* Here's the log: https://1drv.ms/u/s!Arr_R67I9pX_hU346lpBFIvEp7DZ
- I switched from AUTO to FWBA during a mission.
- I cut throttle to 0, pushed the nose down, and intended to glide home.
- The airplane uncontrollably rolled over. Fortunately I had altitude. The airplane flipped over up-right at the last second and landed gracefully.
Here are a few screenshots from the log:
Vibration event starts at line 123
As expected Roll and Desired Roll separate. The airplane is uncontrollable. Note Roll and Desired Roll meet back at line 127. This where the airplane flips back up-right and gracefully lands.
This is typical behavior for a vibration event, right? But the throttle is off. The airplane is gliding.
Here is RC3 out. I killed power at line 114, well before the vibration event at line 123. The airplane is gliding. Brake is set on the ESC so the prop is not even spinning. But still the airplane goes into a typical vibration death spiral.