Quick self intro: I've been into multirotors for only a little over a year. In that time, I went from an RTF Phantom to building my own tri, hex, quad and now working on an X8. I mostly run APM 2.5/2.5.2 on the home-built craft. I usually fly 3.0.1, but have been playing with 3.1.
On my latest quad build, I was on a tuning flight using APM 2.5.2 with Arducopter 3.1rc8. After switching from stablize, to alt hold, to auto-tune, to loiter, to circle, back to loiter, I had a prop just stop spinning with the craft about 60 feet off the ground. I suspect it was the AFRO 20A ESC losing sync, but I have no hard data on that. The other three props were spinning fine still so I don't believe the problem to be power-related.
I unfortunately did not have the power module installed yet, so I don't have logs of the amps and volts. I did have IMU logging enabled though, as I was tuning the quad. Is there anything in the logs that can help me determine the cause of the failure or point to any clues?
I've uploaded my log from that flight. If anyone could give me pointers, I'd appreciate it.