Quad APM 3.2.1. GPS & 3DR radio. This happened 4 times in the last 6 months. Tested today and flew 12 minutes in stabilize mode all ok. Replaced battery and again normal flight. I tested in my back yard. About half way through battery 2, quad motors revved up, veering right crashing into a tree in my yard. I had receiver signal, but radio would not do anything No control. Luckily it hit my tree and crashed. Range was 10’ to 25’ . I have a log file on the flight. I also fly at a model aircraft field, The flight there 2 weeks ago. I flew this quad in Stab, loiter, auto tune, alt hold. and RTL and all worked without a hitch going through 3 batteries. 1 week ago at the flying field it flew normally until the 2nd battery. It veered left, again with no control or shut off crashed into high weeds. Any one have any ideas?
Most of the time it is better to include the dataflash logs (.bin file) rather than just the telemetry (tlogs) logs.