Accident Overview
An aircraft experienced an unintentional engine start while a person was turning the propeller by hand to lubricate the engine. The engine ran at approximately 1700 revolutions per minute. The aircraft was not chocked, tied down, or secured with the parking brake. It traveled across the ramp and struck an empty T-hangar.
Post-Accident Examination
After the accident, investigators examined the aircraft's controls. The magnetos were found in the "BOTH" position. The mixture control was set to rich, the master switch was off, and the throttle was open about 1 1/2 inches. The magnetos were later tested and found to operate normally.
Conditions
The aircraft's lack of restraint—no chocks, tie-downs, or parking brake—allowed it to roll after the engine started. The master switch being off did not prevent the engine from running, as the magnetos were in the "BOTH" position, providing ignition power independently of the master switch.
Investigation
The investigation focused on the sequence of events leading to the unintentional engine start. The throttle being partially open likely contributed to the engine reaching 1700 RPM. The mixture being rich ensured fuel delivery. The combination of these control settings, along with the propeller being turned by hand, resulted in the engine starting.