Incident Overview
The pilot of a single-engine airplane attempted to start the engine but encountered a hung compression stroke. After verifying that the magnetos were switched off, the pilot attempted to free the propeller by hand. As soon as the propeller was moved, the engine started.
Sequence of Events
The passenger seated in the right front seat attempted to stop the airplane using the magneto switch, but the aircraft continued approximately 100 yards, rolled through a guard rail, and nosed down into a canal.
Post-Accident Examination
Following the accident, the magneto switch was found in the 'BOTH' position. The fuel mixture was set to full rich, and the throttle was advanced. The magnetos were subsequently checked and revealed no malfunction.