Accident Overview
During the initial climb after takeoff, the aircraft experienced a complete loss of power. The pilot attempted to return to the airport; however, the aircraft collided with a large warehouse. The airframe was totally consumed in the subsequent post-crash fire.
Engine Examination
Examination of the engine revealed that the spark plugs were excessively worn. The electrode gaps were measured at greater than .025 inches. The maximum serviceable gap for the plugs is .021 inches, with the most desired gap range from .016 to .019 inches. The plug manufacturer indicates that gaps in excess of .025 inches require excessive voltage to fire under cylinder temperature and pressure conditions at takeoff power.
Maintenance History
The maintenance records noted that the last time new spark plugs were installed was in November 1982, 493 hours prior to the accident. The plugs were reconditioned in July 1984, 392 hours prior to the accident.