After my previous crash I've rebuilt my quad and had finally got it flying well, with excellent loiter performance which I tested earlier this week in strong winds and accurate RTL.
Thought I was home and dry on the setup so tonight I set up Auto mode as a new mode on my flight modes and hoped to test it out in calm conditions. I took off and switched to Loiter. It wasn't playing ball at all and kept flying off in one direction (not toilet bowling as far as I can tell). I landed, rechecked, restarted everything, made doubly sure GPS was good, and tried again, still the same behaviour.
I let it go a bit to see if the loiter controller would sort itself out. It didn't and headed off faster and faster in one direction. I switched flight mode back to stabilise. It didn't respond. I tried out and into stabilise again. No response. Eventually I tried switching my transmitter off to trigger RTL failsafe. (I have used this before and it has worked).
The quad stopped, changed direction and headed back to me and downwards faster and faster, over my head, and smashed into the ground at absolutely full tilt. I have a nice onboard video of me running like hell out of the way.
I have absolutely no idea what is going on. To me the log looks like it went into Auto mode (which I am certain I did not request as I have a separate override switch for Stabilise, and even so it wasn't flying anywhere near the waypoints I set). Then RTL was activated OK, but did the wrong thing: it flew in the opposite direction from what it was supposed to, and made more and more extreme corrections until it was flying at full tilt and max throttle. I had to pull the battery to get it to stop, which wasn't hard as all the motors were smashed :-(
Log attached. Please, please can someone come up with some idea what happened here?