Incident Overview
During a preflight procedure, a pilot placed the ignition key on the aircraft's dashboard and proceeded to turn the propeller by hand. The aircraft was not tied down or chocked at the time. The engine started, causing the aircraft to move forward. The pilot attempted to restrain the runaway aircraft but was dragged for several yards before releasing his grip. The aircraft then traveled an estimated 50 to 60 feet before colliding with a hangar.
Investigation Findings
Examination of the aircraft's ignition switch revealed that it was worn and had been set to the right magneto 'on' position. During the pilot's preflight inspection, he failed to detect that the key could be removed from the ignition without first turning the switch to the 'off' position. The worn condition of the switch likely allowed the key to be removed while the magneto remained energized.
Sequence of Events
The pilot's actions included placing the ignition key on the dashboard prior to hand-propping. With the switch in the 'on' position, the engine started when the propeller was turned. The absence of wheel chocks or tie-downs enabled the aircraft to move once the engine engaged. After being dragged, the pilot let go, and the aircraft continued until impact with the hangar.
Conclusion
The incident involved an unexpected engine start during hand-propping due to a worn ignition switch left in the 'on' position. No other factors were identified in the report.