Primary finding
Probable cause
The pilot/mechanic's improper installation of the spark plug, resulting in its separation from the engine. A factor was the unsuitable terrain available in the runway's overrun area.
Investigator assessment
Analysis narrative
The pilot, who is also an A&P mechanic, installed and torqued a new helicoil and spark plug. A satisfactory engine run was completed. During takeoff climb, at 300 feet AGL, 'the engine popped and lost power.' The pilot executed a 180-degree turn, and 'landed fast downwind.' During the landing roll, the aircraft overran the end of the runway and 'encountered a rut and flipped over' damaging both wings. An examination of the airplane revealed that the newly installed spark plug was hanging by its ignition wire.
Source record
Factual narrative
On March 10, 1997, at 1645 central standard time, a Cessna 172P, N65753, registered to Christiansen Aviation, Inc., and operated by the Oklahoma State University Flight School, was substantially damaged during a forced landing, following a loss of engine power near Cleveland, Oklahoma. Visual meteorological conditions prevailed for the proposed positioning flight to Stillwater, Texas, and a flight plan was not filed. The commercial pilot, the sole occupant, was not injured. The flight was originating from Cleveland Municipal Airport at the time of the accident. The pilot, who is also a certificated mechanic, reported that he had installed and torqued a new helicoil and spark plug. A satisfactory engine run was completed. During takeoff climb from runway 18, while at 300 feet AGL, "the engine popped and lost power." He executed a 180 degree turn, and "landed fast downwind" on runway 36. During the landing roll, the aircraft overran the end of the runway and "encountered a rut and flipped over." An examination of the airplane by a FAA inspector revealed that the newly installed spark plug was hanging by its ignition wire, and both wings were structurally damaged. -