Primary finding
Probable cause
The pilot's failure to properly secure the airplane before attempting to hand-prop the engine.
Investigator assessment
Analysis narrative
The pilot of the Cessna 210G was attempting to hand-prop the engine outside his hangar with a passenger in the right seat. During the first attempt, the engine "cranked but stopped." Before the second attempt, the pilot "by mistake increased throttle." Subsequently, when the engine caught, it overpowered the parking brake, and the airplane began to move forward, increasing in speed until it struck another airplane in an open hangar.
Source record
Factual narrative
According to the pilot of the Cessna 210G, he was attempting to hand-prop the engine outside his hangar with a passenger in the right seat. During the first attempt, the engine "cranked but stopped." Before the second attempt, the pilot "by mistake increased throttle." Subsequently, when the engine caught, it overpowered the parking brake, and the airplane began to move forward, increasing in speed until it struck another airplane in an open hangar.