Hello,
It is possible to help me on a crash log ?
During Auto mission, far away from the base ans with no link between drone and i, we lost the drone.
After half an hour of research, telemetry have found the position of the drone.
The drone has dropped for 25 meters after touching a tree.
With the log i can see that during the auto mission, the drone drift from the original trajectory and after that, start a landing above the forest.
I think this is a problem of numbers of sat and when we don’t have enought, drone start a landing.
But in the log, we don’t have lost sats.
So is it possible to help me on this log ?
Here is the link to DL the log :
Thank you very much 
Best regards.
I just had a little look at it but I can assure you that it is not a problem related to the number of GPS satellites. What I think is wrong with it is that it has a resonance problem or something like that, just before the incident the drone starts swinging heavily between plus and minus 10 degrees of inclination in both pitch ,roll and yaw. This eventually causes an EKF FailSafe which activates a LAND flight mode and causes the drone to descend into the trees.
Does the drone have moving parts like the landing gear that can vibrate and cause resonant oscillations?
This is just the first impression I got from quickly looking at the log. I hope this can help you.
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When the crash occured, there was a lot of wind. However, we have an auto mode decent rate of 2m/s. in this case we have some prop wash on the drone (oscillation like you describe it)
Propwash and heavy wind can make error on the drone ? It’s possible that a part of the drone loosened during the flight. If i trust the graphic that you send me, i think that something goes wrong during the flight.
Wind, vibrations (prop wash), loosened parts… I don’t know exactly what happened, but huge thanks for the help If you have other ideas, i’m listening ! Thank you !
Yes, a severe propwash event can definitely be the cause. Besides, if there was a lot of wind, this could have made the situation considerably worse. After something like this my advice would be to make many test flights in manual flight mode. To verify the correct stability of the unit before doing a mission in autonomous mode.
Ok, i understand, for this mission we have increase decent rate and this is probably why it happened.
Thank you for the help Have a good day