In the past few days we had a case of a prop failure in flight. It was 25 kg crop spraying quad, with cube orange and X8 motors. You can check the log here:
The vibe values seem ok before the crash, below 30 m/s/s, but I’ve noticed the clip2 value increasing steadily. According the docs, small values of clipping are normal with hard landings, but it’s not the case here. The same behavior occurs in a previous flight, three days before the crash (also available in the previous link).
However, brand new copters of the same model don’t show this behavior. They stay at zero for the whole flight. In the worst case, they have some small value (<20) of clip2 during takeoff and they stay at this level for the whole flight.
This raises the question: can we assume that this clipping behavior is somewhat related to hardware suffering fatigue? What values of Acc clipping should we consider normal, and when should we worry?
My goal is to find something in the logs (vibe, clip, IMU acc etc) that we can use and emit a warning to clients to inspect the most critical components (motor bearings, propellers, frame arms). It’s better to perform an unnecessary inspection than discover a problem after the crash.
I do appreciate any help or suggestions!