Actually I'm using last firmware version and did six flights without any problem, the last one in the morning, in the afternoon , after I had install a brushless gimbal that use a Matek bec board to supply 12Volts.
Some seconds after take off in Stabilize mode the copter did not fly properly as usualk and was difficult to control , after some seconds he did non respond properly to radio sticks and finally loose completely the control.
I had just the time to move the mode switch since I believed I was in auto mode and the copter point with a diagonal line and motors turning at quite an high speed to the ground.
Looking at the Tlog just some seconds after take off the message "APM initialisation" appears.
I found that strange but in the datalog flash there is apparently any problem with the 5Volts supply .
Help for log analysis will be greatly appreciated .
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I notice something weird looking at the Tlog.
The heading is rotated by 180 degrees , both when the copter stay to land long before arming and after armed.
There was another person present so it is strange that I took off with the rear in place of the front by mistake since there was a videocamera and I turned it on by opening the lcd screen on the left side.
Of course if the copter was rotated by 180° it could explain why I was not able to control it in Stabilized mode and the way it crashed with a diagonal line to the ground with motors at high speed. It would mean I gave the opposite command I should .
I have compass variance errors because the internal compass of the Pixhawk is not reliable so I use only the compass on the gps unit.
Compass calibration was good, during loiter flight the copter flies straight as an arrow.
UPDATE
The copter took off in the right direction but the hood with the GPs and the compass was mounted in the bad direction so the reported heading was rotated by 180° .
Sinve I always flew in Stabilized mode I do not think that it could affect the handling of the copter but in fact the way it crashed it was like I had the radio commands inverted.
In stabilized mode I suppose that the heading is given only by gyros and accellerometers not by the Mag.
An Auto Analysis shows this:
Size (kb) 642.607421875
No of lines 8085
Duration 0:00:21
Vehicletype ArduCopter
Firmware Version V3.4-dev
Firmware Hash 203bc7a6
Hardware Type
Free Mem 0
Skipped Lines 0
Test: Autotune = NA -
Test: Balance/Twist = NA -
Test: Brownout = FAIL - Truncated Log? Ends while armed at altitude 5.24m
Test: Compass = FAIL - FAIL: Large compass offset params (X:90.00, Y:-81.00, Z:-674.00)
FAIL: Large compass offset in MAG data (X:90.00, Y:-81.00, Z:-674.00)
Large change in mag_field (133.29%)
Max mag field length (778.21) > recommended (550.00)
Test: Dupe Log Data = GOOD -
Test: Empty = GOOD -
Test: Event/Failsafe = GOOD -
Test: GPS = GOOD -
Test: IMU Mismatch = GOOD - (Mismatch: 0.30, WARN: 0.75, FAIL: 1.50)
Test: Parameters = GOOD -
Test: PM = NA -
Test: Pitch/Roll = NA -
Test: Thrust = NA -
Test: VCC = GOOD -
When I loaded the log into the log browser the first thing I saw as an EKF_Check-2 error and a Failsafe_EKF1.
This is purely speculation, but I would not be surprised if the gimbal and/or the BEC had something to do with this crash, so I'm wondering, how are you powering the flight controller, Power Module or BEC?
The flight controller is powered by an original 3DR power module.
TheMatek bec board is a power distribution board used only for the two becs ,I removed the buzzer.
After the crash I check 12V power consumption of video transmittter and brushless gimbal and it was 450mAh while the board should provide 500mAh .
In previous flights the gimbal was a standard one with servos powered by the 3A 5Volts bec on the Matek board connected to the servo rail of the Pixhawk. Then the 12 volts current drain was 220 mAh of the video transmitter.
Since under the hood cover there is little room because there is also a Hdmi / Pal converter and a thick Hdmi cable I thought that a traction might have been operated on the cable that connects the main power from Pixhawk to 3DR power module and might originate some brown out event with the reboot of the Pixhawk while in air just after take off.
But I saw no signs of power failure in dataflash log and even after the crash the connectors of power supply were in place.
At the impact the batteries detach , so it is weird that last reported altitude is 5.24 meters it would had take at least a second to go from 5.24 m to the ground , and the impact point is a couple of meters below take off altitude.
The tlog has no flight?
Hi, you were right.
Now I have upload the right Tlog
It should have one.