My first plane is autopilot mode without transmitter fly it but it was fall down immediately

Am using pixhawk 4 .the px4 is placed in my standard plane .calibrate every thing .am not using RC that’s why am not calibrate radio and flight mode so I set NO RC. when am given mission plane then after start the mission . throttle motor was rotating then after am throw the my plane that is flife .what is problem .how to resolve this