Crash with 3.4.4

Copter takes off in Stable, but ignored switching in GPS pos.hold mode, then rapidly loose height, moves aside and hit the tree. Previous flight with same configuration and 3.4.3 was ok. Any ideas?


Here is the basic report that applies:
Test: Compass = FAIL - Large change in mag_field (40.91%)
Max mag field length (702.43) > recommended (550.00)
Test: GPS = GOOD -
Test: IMU Mismatch = WARN - Check vibration or accelerometer calibration. (Mismatch: 0.93, WARN: 0.75, FAIL: 1.50)

So, this means that the GPS was good (good sat count and good hdop)
The change in the magnetic field around the craft and the mismatch with the accelerometers.
Both could cause the crash.
The one thing that gets me , there is evidence of a switch in the flight modes.
But it switched from Stabilize to Stabilize.
And right before the crash another switch from stabilize to stabilize.

Check to see of all of the flight modes are listed as stabilize is what I would do first.

This situation with mag field looks strange for me. Tested ‘compass/motors’ calibration with props attached and it doesn’t demonstrate any suspect values. Vibration also at reasonable levels. Will check rc modes after recovering, thank you!

Yes, I saw the vibes also and agree.
But something tripped that warning… worth looking into.

Flight looks ok. Vibrations are good.

Copter is under powered and is fighting a yaw as motors 1 and 2 are running higher than 3 and 4. Perhaps one of the motors is twisted.

As you gained altitude it was holding it’s own but as soon as you let off it started to fall apart and was unable to maintain yaw any longer. Full power only made things worse.

Trees prevented the unit from getting a good GPS lock.


Thank you Mike!
Also think it’s motors problem - just changed them and possibly 5000/25C battery is not enough.
But i can’t find source of this mid-thrust misalignment: all ESC manually set to same min/max PPM signal (or it’s may be at different levels for some motors?), what else can provide such error? What you mean “twisted” - thrust axis don’t set tot vertical or something else&

Don’t know your setup but if you are using round booms the motor can sometimes twist.


Thank you, yes booms are round, possibly some twist comes in play. Will check it in next test.