Arming or disarming with the rudder stick was refused

What ArduPilot says:

• Rudder disarm: disabled
• PreArm: Non-zero throttle

Plane arms when the rudder stick is held fully right for 3 s, and only with the throttle at zero: “Non-zero throttle” means the throttle input was above zero at that moment. “Rudder disarm: disabled” means you held the rudder fully left to disarm, but ARMING_RUDDER is 1, which allows arming only; disarming with the rudder needs 2. A plane that counts as flying refuses a rudder or ground-station disarm too, without any message.

What to do, most likely first

1. The throttle stick was not fully down.

   FixPull the throttle all the way down, then hold the rudder fully right for 3 s.

2. The calibrated minimum is below what the stick really gives at the bottom, so the bottom is not zero.

   CheckWith the stick down, the throttle bar in the Radio Calibration screen should read RC3_MIN, give or take RC3_DZ.

   FixCalibrate the radio again.

3. You wanted to disarm with the rudder, and ARMING_RUDDER allows arming only.

   FixSet ARMING_RUDDER to 2, or disarm from a switch (RCn_OPTION 153) or the ground station.

In a mode where the autopilot controls the throttle (AUTO, TAKEOFF) the motor can start soon after arming: keep clear of the propeller. In 4.7 these two checks moved to code shared with Copter and the second reads “Disarm: rudder disarm disabled”.

Parameters to look at