AC3.3.1 unexpected position change during auto LAND = Crash

moved this post here from github per Randys recommendation…see the link for the attached details of the thread and the attached bin file…

Randy, as per your last reply the roll issue you mentioned was when the copter impacted my truck :slight_smile:
it was still in the air and then it tumbled to the ground…so its not a mechanical issue other than the copter slamming into my parked truck…can you please help keep looking for another possible cause? deeply appreciate your support…thanks

here is a video link from onboard camera

This looks like a GPS position error. I would check the plot of the GPS position and see if went in the opposite direction as your flight did when it landed. Doppler effect from the roof of your house.


yes it definitely had something to do with GPS2 being way off base…because GPS2 is showing a ground course in the opposite direction of where the copter actually flew to and the GPS2 also reported speed was all over the place, where GPS1 shows the correct ground course and speed (and lats/longs), oh and to top it off GPS2 was also showing increase in altitude!!! where GPS1 tracked the normal descent…so I dont know what could have gone so wrong with GPS2, because number of sats and HDOP didnt change throughout any of this

so no more 2nd GPS for me I suppose, because there was no reason for AC to have switch to GPS2 when GPS1 always had lower HDOP, so there is something most definitely wrong with how AC handles GPS switchover which Randy eluded to is being worked on the 3.4 release

I opened an enhancement request anyways, as I believe even with one GPS , its sort of dangerous to rely on GPS signal during an auto LAND procedure, a rapid and unexpected GPS position error during this low altitude and proximity to people or property is dangerous, and could cause damage or injury which should be avoided whenever possible. I suggested that copter rely on other internal navigation, rather than GPS, during a LAND procedure (i believe it already does not use GPS during an EKF_FS scenario). not sure if others agree, suggestions would be great…