What happened
A pilot attempted to start the engine of an aircraft using the hand propping method. During this process, the pilot's wife, who is a non-pilot, was seated in the right front seat of the aircraft. The pilot stated that he had set the parking brake before exiting the plane to begin the procedure.
On the third attempt to hand prop the engine, the aircraft started unexpectedly. The pilot attempted to stop the moving aircraft by pushing against the leading edge of the right wing, but he was unable to halt its progress. The aircraft accelerated across the ramp and collided with another Piper aircraft. This impact subsequently caused the second aircraft to strike a Cessna 172. There were no fatalities or injuries reported in the collision.
Safety message
According to the FAA Flight Training Handbook, it is recommended that an engine never be hand propped unless a qualified person who is thoroughly familiar with the operation of all controls is seated at the controls and the brakes are properly set.