Incident Overview
Witnesses reported seeing the airplane at an altitude of 300-400 feet execute a steep left turn. After leveling the wings briefly, the nose dropped and the airplane descended in a near-vertical attitude. The left wing then collided with the top of a commercial building, remaining on the roof while the rest of the airplane slid down the side of the building in a nose-down orientation.
Pre-Flight Reports
Before takeoff, the pilot and a passenger informed two mechanics that during an earlier flight the engine had detonated and lost power. The mechanics offered their opinions on the possible problem, but the pilot did not pursue further action, and neither mechanic inspected the engine.
Post-Accident Findings
Investigators examined the engine and found the number two cylinder exhaust valve appeared tight in its guide, and the exhaust valve spring pocket contained excess carbon. Additionally, the number three piston head showed signs of excessive heat. No other evidence of a mechanical failure or malfunction was discovered.