The Accident
A pilot attempted to start an airplane's engine using the starter but was unsuccessful. The pilot noted that this had been an intermittent issue, having hand-started the engine once during five previous flights the prior weekend. Unable to find personnel from the fixed base operator, the pilot decided to hand-prop the engine without assistance. The pilot asked a non-rated passenger seated in the right front seat to apply the brakes.
With the airplane unsecured and the throttle applied slightly, the engine started. The airplane initially remained stationary but then began to move. The pilot tried to board the airplane but could not, and the aircraft accelerated. It turned left, traveled between two rows of parked airplanes, and struck several parked unoccupied airplanes. No injuries occurred to the front or rear seat passengers or on the ground.
Pilot's Account
The pilot stated he did not show the passenger how to activate the brakes. He believes the passenger may have inadvertently applied left rudder in an attempt to stop the airplane, though the passenger said he did not recall doing so.
Background Information
The Federal Aviation Administration (FAA) Pilot's Handbook of Aeronautical Knowledge includes a section titled "Hand Propping." This section advises against allowing a person unfamiliar with the controls to occupy the pilot's seat during hand propping. It also recommends placing chocks in front of the main tires or, if not feasible, securely tying the airplane's tail. Excerpts are contained in the NTSB public docket.