The commercial pilot was conducting a personal flight in the Cessna 150M.
He reported that, several minutes after takeoff and while en route to his destination airport, the engine began to run roughly and lose power. He attempted to restore power without success.
He then maneuvered the plane for a forced landing on the fairway of a golf course in Key Biscayne, Florida. The 150 touched down on wet grass, and the pilot was unable to stop it before it hit two palm trees, which separated the outboard sections of both wings.
Post-accident examination of the engine revealed that the intake valve of the No. 1 cylinder had failed due to fatigue, which would have resulted in the partial loss of engine power and engine roughness reported by the pilot. The origin and the extent of the fatigue region could not be determined due to postfracture damage.
Further examination of the tip of the valve revealed an abnormal contact wear pattern likely caused by either misalignment relative to the valve seat, valve guide wear, or sticking between the valve stem and the valve guide.
A review of maintenance records revealed that new cylinders had been installed when the engine was overhauled about 904 total flight hours before the accident.
Probable cause: The fatigue failure of the No. 1 cylinder intake valve, which resulted in the partial loss of engine power.
NTSB Identification: ERA16LA027
This October 2015 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.
