Summary: Copter took off at STABILIZE - smooth flying a second or two - FENCE BREACH - autopilot LAND - strong over reacted ROLL - parachute eject/motors off - crash.
Main problem is solved:
- requirement for GPS lock on ARM was disabled
- copter were GPS failsafe during take off
- copter flew smooth a while
- GPS 3D lock was reached
- False Fence Breach
- LAND setting activated on Fence Breach
- Strong ROLL movement
- I switched "emergency switches" before collision to anyone
- motors off - crash from an altitude of a meter
How to increase change for avoiding this Fence Breach glitch
- Don't disable GPS check on prearm check
- If you do, unplug GPS module or disable Fence feature
These solutions are results of my own investigations and readings from forums and has not been verified by anyone. This could be correct or wrong solution, totally or partially. (I remove this text when some developers confirm this is correct)
If GPS failsafe is set as default RTL, copter might fly anywhere without control until pilot realizes Autopilot is kicked in and disables Autopilot by switching back to STABILIZE.
Smooth flight AUW 10kg before first crash. Like this my bird flew before a crash earlier this summer caused by compass.
Replies
After new investigations I'm quite sure it was Fence Breach as you Floyd said. Slow motion tlogs show Fence Breach and LAND.
Why it had so poor landing after a second or two very stable flying, is still unknown.
tlog is attached.
Failsafe kicked in same time I was starting take off and added throttle at time 9:48:44.
Still I was able to take off and Droidplanner didn't give any warnings. I also got fence breaks afterwards.
I have done range checking twice with all radio links on and result has been more than 200m through the forest on the ground. Min throttle on radio is set to 1000 and failsafe is much lower. I raised min throttle just because Taranis radio off PWM was so high. This way it has some cap to failsafe.
Does anyone could explain what happened?
Also how did you arm with bad GPS? Did you skip the pre arm GPS test? I feel if you have skipped the prearm GPS test then all GPS functionality including failsafes dependent on GPS should be disabled automatically. Which is obviously not the case.....
Here this copter stays on the ground until I know what happened. Fence came after crash so it is not a problem.
One thing I remember on night that On droidplanner I saw copter like moving although it was on the ground. That's perhaps because of ON/OFF GPS lock. I saw many lines where Droidplanner thought copter were flying while standing on the ground.
Also on video I heard something about "waypoint". I didn't set any waypoints, perhaps did weeks ago while learning Droidplanner after installation.
Flight mode was all the time Stabilize.
I have skipped GPS on prearm check because otherwise in here its imposssible to fly at all. Third image shows it gave a lot GPS warnings including fence and I was flying stabilize.
What was weird is that it was stabilize and flew quite nicely in the beginning and then without any stick input dropped power from some motors. It was trying to ROLL but why without stick input. Second image shows that clearly how half of the motors were only about 1200. And it was not flipping, it was ROLL to perhaps max angle which I had much lower than default.
I'll check if logs are available from Droidplanner.