Unattended 360 figure on Tricopter

Hi, while I was gently cruising on my Tri, it suddenly did a 360 degree figure. It was well made but so scaring :slight_smile: Anybody that could explain that is welcome as since that I am afraid to pilot it again…
Here is the anonymized log. Problem occured at around 106s.
Thanks
Log file : Amazon Drive
UAV log viewer video : Amazon Drive

Seems that no one uses Tricopters anymore :sleepy: Of course, this is not the best platform nor the more efficient but it is what makes it interesting :slightly_smiling_face: I lowered my D term a little bit and it did not occurs during my last flight.