Incident Overview
A pilot reported planning a flight in a single-engine airplane. During the pre-start sequence, the engine's starter would not engage. After turning off the switches and setting the parking brake, the pilot exited the cockpit and rotated the propeller by hand to manually align the starter mechanism.
Unexpected Engine Start
While rotating the propeller slowly, the engine started unexpectedly. With the pilot outside, the airplane moved forward under its own power.
Collision and Fire
The uncontrolled aircraft collided with a hangar and an electrical transformer box. A post-impact fire ensued, completely consuming the airplane. The damage prevented any examination of the cockpit, brakes, or electrical system.
Investigation
The official investigation confirmed the sequence of events but did not assign a probable cause. The fire made it impossible to determine why the engine started or whether the parking brake or switches were properly disengaged.