Near crash analysis requested [log file and video inside]

Hi All,

Long story made even longer :laughing:

A couple of weeks ago I wanted to upgrade my firmware from 3.2.1 to 3.3 stable.
After this upgrade I got numerous failures before arming like: bad AHRS, compass inconsistancy and others.
So my idea was to revert back to 3.2.1, unfortunatly mission planner had “forgotten” that one already.
So I downloaded it and flashed it back (I thougt at least). Dropbox firmware download

After having several resonably fine flights (these were less stable than before) I had a bit of a surprise today.

After take off everything looked fine (at least nothing special), tested loiter and RTL it seemed to work.
Than I tested my “signal lost” by switching off my transmitter, this did not work and I needed to react quickly (I tried 2 times).
After this I tried hovering at around 50 meter with Loiter, here I noticed some instability (I should have seen this warning and should have landed immediatly).
After a while I rotated left and noticed that the hexa was flying away from me and gaining height, this was not my intention so I reverted to RTL. This made it even more “angry” and it gained more height, in the meanwhile my telemetry was shouting all kind off warnings at me like: Bad AHRS, Compass variance and others just like in the 3.3 firmware.
So than I switched to stabilize and “landed” my hexa, unfortunatly it was a bit further away and I could not notice my forward speed so I broke one landing leg connection.

I am sorry for this long post and for all of you who are still reading can someone please investigate my log files and gues what has happened?

Thanks Johan

Dropbox logfile download

The flight video

A picture of the hexa

Check vibrations, see log IMU.AccZ ?
This is the usual reason to rapid elevation gain - I’d wish people learn that soon :slight_smile:

Hi Andre,

Thank you for your awnser, do you think that the vibrations also cause the Bad AHRS and EKF Variance?
What would be the maximum allowable vibrations number?

Dropbox telemetry log

Greetz Johan

check out … vibration/

  • yes, the Bad variance is most likely caused by this.