I have modified my Bixler2 to quadplane and test flown in QSTABILIZE mode twice without problem. Today, shortly after taking off in QSTABILIZE, I changed to FBWA and after a couple of turns at low altitude, the plane suddenly yaw uncontrollably and crashed. Pls see attached log and param and suggest the possible reason of crash.
https://drive.google.com/file/d/1Ii4zBM86_CcnjdqB3VfbkjUTgKDx9FTn/view?usp=share_link
https://drive.google.com/file/d/1GaS-YQ_KarZWBk1ZVJSMx0Vy7HOoHQJl/view?usp=share_link
Thank you,