Incident Overview
A pilot performing aerial application of sterile pink bollworms landed the airplane for a restroom break. After setting the engine to idle and engaging the parking brake, the pilot exited the aircraft. While in the restroom, the pilot heard the engine pitch change and the parking brake disengage. Exiting the restroom, the pilot observed the airplane moving across the parking ramp.
Sequence of Events
The airplane accelerated to approximately 30 mph as it departed the immediate vicinity. The pilot chased after it. The aircraft then traveled through the airport perimeter fence, struck a sign, crossed two roads, and eventually came to rest adjacent to an almond orchard.
Damage Assessment
The airplane sustained structural damage to the left wing strut and the leading edges of both wings.
Pilot Statement
The pilot reported hearing the engine pitch change and the parking brake disengage before the airplane began to move. The pilot provided no additional details about the cause of the brake disengagement.