Had a major flyaway and crash today - AC 3.1.5. Copter was completing a land waypoint in an auto mission, and I switched to stabilize. As soon as I switched to stabilize the copter pitched forward hard.
At the moment the control for gimbals (Servo or Brushless) is to provide a PWM output that 'should' correspond to an a servo position or brushless controller angle.
It would be great if the APM community could define a mechanism for gimbal sensors or