Hardware is PixHack V3
I had flown the flight path (obvious pattern in the attached picture) or something similar, for nearly 15hrs over 3 days prior to the flyaway. I tuned the basic PIDs (autotune) and TECS and Nav Controller in the early hours and was mostly putting time on the aircraft and working on tuning the gasoline pusher engine. The aircraft was navigating very well, in my opinion, short of some altitude variations but it was an extremely convective day and it had flown very smooth in the early morning air. Being gas, it is fairly easy to keep tabs on the aircraft location and health and I was monitoring it from my little ground station outside (card table with laptop and RC Tx) Well into my second flight of the day I thought the engine had died, and when I looked to where I new it was, to my surprise it had not made its 90 deg turn to waypoint #2 and was simply so far away it was hard to hear! I glanced at my laptop and it appeared that I had lost telemetry (not true) so I quickly looked at the signal on my tx (TBS Crossfire) and saw that I was still connected. I couldn't see the aircraft anymore when I looked back up so I manually initiated failsafe (Qland). That's when I noticed that I still did have telemetry stream, and could see the aircraft location. I drove my car to retrieve the aircraft (which survived in pretty good
I seems to me that the FC was very aware of the fact that it was not heading towards and was getting farther and farther away from its next waypoint?
It was not a mechanical failure, all surfaces still work.
So short of the bad compass health which doesn't seem to affect performance much in FWD flight (thanks EKF?)
Anyone have any ideas on why this may have happened suddenly to an aircraft that has been very reliable?
Ill link the .tlog as soon as it uploads
Any insights would be appreciated.