Accident Sequence
The pilot reported that the airplane was difficult to start after numerous fuel priming actions and two start attempts. The engine started on the third attempt after using what he described as a flooded engine start. Approximately ten minutes after takeoff, the engine began to sputter and the revolutions per minute (rpm) dropped to 1,500. The pilot applied carburetor heat, selected alternate magneto positions, turned on the electric fuel pump, and adjusted the mixture, but these actions did not restore power. The pilot noted that the power fluctuated before the engine lost all power. A witness on the ground observed a fluid coming from the airplane as it flew overhead; the fluid landed on the witness's windshield and subsequently evaporated. During the forced landing, the airplane impacted the roof of an abandoned two-story building.
Investigation Findings
An examination of the engine, fuel, and ignition systems revealed no anomalies that would have prevented power production. Soot and carbon-like deposits were found on the carburetor's venturi and on the spark plugs. A carburetor icing probability chart indicated that carburetor icing was not probable under the conditions at the time of the occurrence.