Crazy Crash: Reason Power loss but motors Running?

Hi Guys,

i am pretty new to Copter flying but really like Ardupilot :slightly_smiling_face:
It is the second time now, that my copter “crashes” without a reason with the following pattern:

While loitering without touching any stick or button: suddenly fast descending (maybe 7-10meters/s) with no control possible. Motors running.

Last time, i thought i just missed the battery warning and this was the “land” action triggered, but wondered why the land was so “hard”… didnt pay more attention to it (silly). It was about a few minutes flight time, so i guessed my time estimation was totally wrong

now: same again, landing was so hard that some parts are broken. I tried my best to analyze the log, and it seems that battery voltage was not the problem… what would you think?

(couldnt upload because of file size, so here:)


Logfile ends abruptly, no indication of fast descent or crash. Perhaps it is a wrong log.
(Nota Bene : upload bin log files not a .log ones.)

Looks like you had a radio failsafe event then when it came back you had your throttle at 0.