The main loop is too slow for a QuadPlane

What ArduPilot says:

• PreArm: quadplane needs SCHED_LOOP_RATE >= 100

The flight controller's main loop runs at less than 100 Hz. A plain plane runs at 50 Hz, too slow to keep a hovering aircraft level; when Q_ENABLE is already set at power-on, the default becomes 300 Hz. The rate is read once at start-up, so a change of SCHED_LOOP_RATE or of Q_ENABLE takes effect only after a reboot.

What to do, most likely first

1. Q_ENABLE was set and the flight controller has not been rebooted since, so it still runs at the plane's 50 Hz.

   FixReboot the flight controller. If SCHED_LOOP_RATE was never saved by hand, it comes up at 300.

2. SCHED_LOOP_RATE is saved with a value below 100, for example from a plain plane's parameter file; a saved value beats the QuadPlane default.

   CheckRead SCHED_LOOP_RATE after a reboot.

   FixSet SCHED_LOOP_RATE to 300 and reboot.

Parameters to look at

Where to do it:Parameter Compare & Migrate