The launch was felt and then rejected: the motor stays stopped

What ArduPilot says:

• Timeout AUTO
• Bad launch AUTO

After “Armed AUTO” the launch was not accepted, so the motor stays stopped and the wait begins again. “Timeout AUTO”: when the delay TKOFF_THR_DELAY had passed, the GPS ground speed was still not above TKOFF_THR_MINSPD. “Bad launch AUTO”: during the wait the nose was 45° or more up, or 30° or more down, or the plane was banked more than 30°, which is no attitude to start a motor in.

What to do, most likely first

1. The plane was shaken or bumped rather than thrown, so it had no speed when the delay ended.

   Check“Timeout AUTO” follows “Armed AUTO” while the plane is still in your hand.

   FixThrow it firmly and level. For a hand launch the parameter notes suggest TKOFF_THR_MINACC about 15 and TKOFF_THR_DELAY at least 2; with a pusher propeller keep TKOFF_THR_MINSPD at 4 or more.

2. The plane stands on its wheels: with TKOFF_THR_MINACC 0 and a speed required, the speed never comes, and the two messages repeat every 2 s.

   FixFor a take-off from wheels set TKOFF_THR_MINSPD to 0 too: the motor then starts TKOFF_THR_DELAY after arming. Stand behind the plane.

3. The plane was held nose-up or banked while it waited, or was thrown steeply upwards.

   CheckThe message is “Bad launch AUTO”.

   FixHold the wings level and throw straight ahead, only slightly upwards. A launcher that holds the plane steeply is what FLIGHT_OPTIONS bit 2 exists for.

Parameters to look at