Very strange crash, help needed to find root cause

A few weeks ago, we had a very strange crash which we have a hard time to determine the root cause of the problem.

We took off, hovered to our start altitude and started forward flight. When we reached transition speed, the plane started banking left and right violently and within a few moments, crashed.

From analyzing the log file, we come with 2 possible scenarios:

  1. One of the multi rotor motors had a failure
  2. Ailerons didn’t get signal, maybe due to cable connection problem

Of course we would like to understand what went wrong so we can take actions to avoid this to happen again.

The .bin file is here:

Please help.

@tridge2 Can you please have a look if you have time?

@tridge Sorry to bother you. I really don’t have a clue where this problem came from. Could you please help?

It does look like ailerons were completely ineffective. Unfortunately POWR.VServo doesn’t log anything useful, presumably you don’t have power connected to the servo rail?

Thanks for your time. Yes, the servos get their power from a separate power supply for redundancy. But it should be connected to the servo rail for monitoring. Thanks for reminding. We couldn’t come to a final conclusion, I had the opinion about the servos not reacting, my friend insisted on the multirotor malfunctioning. We now have a 3rd opinion and can close the case. :slight_smile: