I gave an auto mission of takeoff to a waypoint of 40m altitude, after 15 mins of video recording i initiated RTL it lands and then the motor does not stops and disarm, instead the motor gains some speed and the hex topples and crash disarms. even in the stabilize mode i cannot disarm through rc has zero throttle and left rudder it yaws aggressively instead of disarming This is 4th time in a day and now has become dangerous.
Firmware: hexacopter 3.6.9
this same happens in loiter and stabilize mode also after landing
I recall seeing an issue with disarm because the craft doesn’t think it’s on the ground. Make sure that your accelerometer and compass are calibrated. Also, you could put arming on a switch. My suggestion would be to save a copy of your config, wipe the flight controller, and perform a fresh install and setup. Fly it manually without a mission first and see if it’ll disarm on landing.
As David told, save your parameters, load a rover firmware to erase the one on your copter and load back to a fresh arducopter firmware.
After a complete wizard, you would have better results.