Why did the helicopter roll over and crash while flying?(RCOUT.C8 in a high position)

The flight altitude was about 2 meters. After falling to the ground, I found a warning sound that the motor did not receive a signal.

loglink:

https://drive.google.com/file/d/1qRxuO1wAMghMmuPsBwbqehTODWkhjJUq/view?usp=sharing

@blue0827ww it appears that the flight controller lost power because the log ends abruptly. It doesn’t show the crash. Also you said that you heard the ESCs indicating they lost signal. Was the flight controller powered when you got to the aircraft? If the flight controller rebooted, it should have saved another log file that would have some important information regarding why the flight controller lost power or rebooted. Check the flight controller to see if another log was saved after the one you provided in this thread.