I recently did a mission where I could not reach my outer waypoint whitout setting RC F/S to “continue with mission”. I had a solid telemetry link, and in an unrestricted area, so I thought it would be safe enough.
When I reach the distance where it looses the rc link, the copter starts spinning rapidly, and also does some pretty violent pitching. Because of the low update rates, it looks like turbulence and heading problems in the Mission planner. Regardless of this behaviour, it still tracks like planned, and on return from the outermost waypoint, it all suddenly looks good again. The video from the flight shows that it could not have been far from loosing attitude control.
We have since found out that you have manual yaw override when in AUTO, and concludes that this is still true when the Pixhawk goes into failsafe “continue with mission”.
The problem was receiver failsafe was set to go to a low value on all channels, and not just throttle.
So basically the quad got full left yaw input, the moment it lost its rc link.
Now I know how to avoid this, but I think this is must be considered a bug in the firmware?