Arduplane Pixhawk Crashes turning stall after brief flight

ArduPlane Plane 3.8
1

Hi friends.
I have had big problems on my Pixhawk.
After take off on manual mode or Stabilize, I did 1 or 2 circles for taking altitude I change to Auto mode, so then the plane went to the first and waypoint but when it was closer or over the second waypoint, the plane did a hard turn to the right side and nose down entering on high g turn stall.
At that point I change from Auto mode to Stabilize, but it was so late to recover the plane crashing on a wheat field.
I have been trying to solve this problem for more than 4 or 5 moths and with 7 flights I have had 7 crashes, all with the same charastaristics, just the last flights was a bit more time flying, but I am really desappointed.
So, I will upload the videos now.
If someone have had similary problems, please I will be very grateful to heard about your solution or suggestions.

Thank you

2

FYI - i moved the category to Plane. It was created as “Blog” so it was appearing on the front page of ardupilot.org.

3

You will also need to up load a Flight Controller log of at least one of the crashes for people to look over for the cause and hopefully, a remedy.

4

Yes I know, I’m uploading the files, but in the mean of while, I left to you the autoanalisis of the second flight.

\Segundo vuelo prueba despegue manual + automatico crash.log
Size (kb) 182106.017578125
No of lines 2553762
Duration 1:00:03
Vehicletype ArduPlane
Firmware Version V3.7.1
Firmware Hash 22b5c415
Hardware Type
Free Mem 0
Skipped Lines 0

Test: Autotune = NA -
Test: Brownout = GOOD -
Test: Compass = FAIL - Large change in mag_field (1274.43%)
Min mag field length (97.36) < recommended (120.00)
Max mag field length (1338.08) > recommended (550.00)

Test: Dupe Log Data = GOOD -
Test: Empty = GOOD -
Test: Event/Failsafe = GOOD -
Test: GPS = FAIL - Min satellites: 0, Max HDop: 99.99
Test: IMU Mismatch = UNKNOWN -
Test: Motor Balance = NA -
Test: NaNs = GOOD -
Test: OpticalFlow = FAIL - FAIL: no optical flow data

Test: Parameters = GOOD -
Test: PM = NA -
Test: Pitch/Roll = NA -
Test: Thrust = NA -
Test: VCC = GOOD -

5

You have a bad calibrated compass and no GPS , so I guess that the plane is not able to estimate his speed in Auto mode this could lead to problems.

6

Yes I know, but when the flight started I didn’t have this warnings, if not, the Pixhawk wouldn’t be armed. But it’s true, sometimes and suddenly my pixhawk lose his position (I could see it on my ground station, as warning). And by other way, the EKF alghoritm should control the plane, despite of the lose of gps signals.
Also, the result of autoanalisis is taking under account that the plane have had a crash?, because, obviusly when it hit the ground, gps and compass could fail, but it was before or after the crash???
Specifically, I have this doubt. Why the pixhawk do a turning so hard? I couldn’t find this ond the logs and tlogs files. I just can see control comand and attitude of the plane, but not why it did that…I don’t know. If someone here have had similar problems, please give me a hand.

Thank you

7

Here is the video…