Drone Crash in Disarm

PX4 Autopilot
1

@DevTeam Today we were testing our tilt rotor VTOL.

Pixhwak 6C,
PX4 V1.14

During testing, when drone was on the ground, after few seconds it got disarmed automatically. Not from the remote directly from the Pixhawk 6C.

After that, we disarm and put kill switch ON on the radio.

All of a sudden, the drone got some signal and motors started turing at high speed and drone got crashed.

Kill switch was on and it other switch was in disarmed position (we confirmed, as no one touch the remote during that time)

2

Your vehicle should disarm on the ground if you don’t take off fast enough Parameter Reference | PX4 User Guide (main)

If you want comment on the rest you will probably need to provide a log: Flight Reporting | PX4 User Guide (main)

Sorry about your vehicle - must be very frustrating :frowning:

1 Like
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It disarms after 10 seconds of not taking off by default. You can change that by setting COM_DISARM_PRFLT to a longer timeout or to -1 to disable the feature.

We’d need the log of the incident to find out what happened. Sorry to hear about the crash.

4

Hii, thank you for the reply. I checked the parameter COM_DISARM_PRFLT and it was 10 by default so it make sense that it disarm automatically as we did not take off and checking for other things.

The auto disarm before crash could also be because of COM_DISARM_LAND = 2.0
as when i checked the log file, it said landing detected and disarmd by landing.

There is no log file for the crash apparently.

I have one more question,

standard config:
3 (FL) 1 (FR)
2 (RL) 4 (RR)

The drone was on ground all the time, as we were checking the correct reaction from drone according to pilot command.

log file: https://review.px4.io/plot_app?log=582994c6-17cf-451b-9234-42a5acea119b

as can be seen in log file, during 1:45 to 1:53 there is pitch command and at that point two motors i.e 2 and 4 stopped completely.
Motor 4 stayed off even after removing pitch.

The drone weights around 10 kg and 4 12s motors with 16 inch prop can produce 7.5 kg so there is enough room. The ESC calibration and other required calibrations were also performed before flight.