FX4-2 N8508H accident near Cartersville, Georgia

Probable cause

The failure of the engine-driven oil pump drive coupling resulting in a loss lubrication and subsequent loss of engine power.

NTSB analysis

The pilot and certified flight instructor (CFI) were practicing takeoffs and landings. On the fourth takeoff, the airplane lifted off and the engine temperatures were within the normal range. At traffic pattern altitude, the pilot reduced power and turned left to enter the downwind leg of the traffic pattern. Shortly after making the turn, the engine experienced a total loss of power. The CFI took control of the airplane as the pilot restarted the engine. The engine regained full power for about five seconds and then shut down again. The CFI maneuvered the airplane for an off-airport landing in a pasture adjacent to the runway. The airplane landed hard and subsequently pivoted up on the nose cone before coming to a stop. During a postaccident examination and test run of the engine the two-cycle engine started and ran continuously on the airframe. When the engine was accelerated to full throttle, it lost power. Further examination revealed a failure of the engine-driven oil pump drive coupling. The resultant loss of lubrication and increased heat melted the rear piston lands over the piston rings. This led to a loss of cylinder compression and subsequent loss of engine power.

Text from the NTSB. Open the NTSB docket for ERA10LA179 for the full record.