Thank you very much for the help. At least we know it wasn’t something we did wrong 
. And we were flying when you released the fix… Such bad luck.
The Here GPS. We always buy the bundle from jdrones.
Can you please send a picture of the GPS?
Our here gps is not fitted with that compass, so if that compass is being detected, then there may be a different issue
Did you have a secondary GPS?
We use other compass. The compass we use is
No, we not use secondary gps.
ok, @jani_hirvinen, which mag is on that? Is it the QMC5883L?
The here is not fitted with this magnetometer
With all due respect, I am satisfied with the answer from @tridge. Of course it is always a tragedy to loose an airplane due to some bug.
But for me, this is fully acceptable. This is open source software, and thanks to the hard work of so many people, it is freely available for everyone.
I consider a crash like ours a valuable contribution to the community. It will make the software better, more reliable and stable for the whole community.
I appreciate your efforts to help investigating and I hope it will leed to even more understanding of the failure.
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Why would that airspeed/compass board claim to have a HMC5983 mag yet the device ID identifies it as a QMC5883L would be my question.
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The reason that we continue to investigate, is that according to the components you say you had fitted, the detected Magnotometer is not fitted to your vehicle, so we need to find out if that is correct.
If the suspect magnetometer was fitted, then Tridge’s solution will be satisfactory.
If the suspect magnetometer was NOT fitted, then that would indicate a secondary issue that needs to be cleared up.
Can you take a close up picture of your magnetometer on the airspeed sensor?
No problem. Please find attached:
Depending on the age of the airspeed/mag board it’s either HMC5983 or QMC5883.
Awesome, so we are not chasing another bug! Thanks Jani!
Thanks! That is consistent with the conclusions above.
I’d also recommend that you not use that specific compass again as it was clearly acting up. The new firmware will prevent that misbehaviour from causing the watchdog reset you saw, but it may still get bad data. In the few seconds before the lockup it gave some odd spikes that it really shouldn’t be giving
Dear Jani,
Now that there is a definite conclusion, we need your help. We have a total of about 7 uav, equipped with this airspeed / compass hardware.
Of course we cannot continue to fly with this as it may potentially leed to a crash.
Is there an alternative available?
ahh, sorry, I wasn’t very clear. I didn’t mean to stop using this type of sensor. I just mean this individual sensor as it shows unusual noise. I really mentioned it as I can see you’re flying a large plane over populated areas and it wouldn’t be worth continuing using a sensor that has mis-behaved. The same would go for any mis-behaving sensor.
The QMC5883L sensor is in general fine, but in this flight log this one clearly misbehaved.
Cheers, Tridge
Ah, OK. Understand. But I’m thinking to change anyway since this incident.
I noticed the Here2 has also built in compass. So I will change from this airspeed/compass combination to only airspeed sensor and then change the GPS to here2 and use that compass.
You think that’s a good idea?
Anthony, best solution is to update to the latest firmware where ChibiOS interrupt storm is fixed. This is just to make sure that it won’t happen again.
We are happy to replace this individual sensor for you.
as long as you upgrade to 3.9.11 then the QMC5883L as a sensor is fine to use, but if you did want to disable it and just use it as airspeed and not compass then you can set:
COMPASS_TYPEMASK=4128
that will disable the use of any QMC5883 compass.