We did a short test flight with our VTOL plane. We took off with QSTABILIZE mode and switched to AUTO. It flew well up to the point when it came back with RTL and switched to QRTL near home. Right after switching to QRTL the plane started a descent and a rapid yaw. After a bit panicky moment the pilot managed to steer the plane to a nearby layer of deep snow, so no bigger damage.
Looking at the log (ATT, Yaw, DesYaw) it seems to me that the autopilot did the yaw on purpose? Does anyone have a glue why this would be? Compasses (internal and Here2) were calibrated right before flight and heading matched true heading.
I think you were just abit unlucky that RTL was so close to home the QRT triggered when the aircraft was still banking at a little more than 30 deg. This then caused QRT modes to struggle to regain control after the transition.
Thanks for the reply. I don’t think that is the cause. This happened on an earlier flight where the last waypoint was further away. In that case it switched to QRTL and started descenting normally and after a few seconds started a similar yaw turn.
And in the log you can see that in the ATT the DesYaw value changes along with the Yaw, so does that not mean that the autopilot intented to do the yaw for some reason?