Need help on log analysis w crash

Hi all
I really need your help trying to understand the reason of a strange crash I had.
I am running a octo-x with pixhawk and fw 3.3rc10
I finished a test surveying and during the way back to the take off wp I loose one rotor( yes! it flew away with the propeller). Since the copter has been calculated for rotor fail redundancy, it was able to level and no problem happend for the next few seconds.
Then when it start the landing, motors stop all together and you can immagine the disaster falling down from almost 30meters…
Now checking log: I can clearly identify when the motor fails, but the really strange is that all RCOUT channels (from 1 to 8) went to zero.
My first idea (before reading the logs) was a second failure due to the over load of the second coxial motor, but this is not the case! THe log clearly show the all pwm went down to zero (and motor/esc are still working)

Any hel will be rally appreciated!
Thank you so much guys! :smiley:

I just noticed that at index 93810 all RC out channel goes to zero, while RC in show the correct values.
It was flying at 63m AGL…
Last correct command was at index 93779
Also @93766 EV id = 54: does anybody know what this stand for?

Q: “Also @93766 EV id = 54: does anybody know what this stand for?”


Perhaps channel 8 is set to Emergency Stop? Try graphing CTUN Alt + RCIN Channel 8.

this is exactly what’s append… :open_mouth:
the problem is : how this can be explained???

this is my conclusion…

I never intentionally set rc8 to emergency stop: checking the configuration inside Mission planner, I saw that RC8 is set to a “blank” value ( I know it should be set to “do nothing”)

This morning I upadted to latest release of Mission planner and fw3.3 and after that the values is now setted to emergency stop
So my question is : is it possible that having tested different beta release of the fw 3.3, one of them may have this value setted to 54 ???

In your flight log, looking at lines 140 and 141 for CH7_OPT and CH8_OPT the values are 18 (land) and 31 (emergency stop) respectively. Zero is the value for “do nothing” for Channels 7 and 8. The land function (CH7) was never invoked according to the logs, instead CH8 (emergency stop) was activated.

Thanks for the time spent looking at the log. :smiley:
The setup was exactly as you described, but I still don’t understand how the CH8_OPT can have been set to “emergency stop”.
Altought I never intentionally set the value to “emergency stop” … it may have been my only fault… :confused: