Piper PA28R N41AT accident near Prairieville, Louisiana

Probable cause

Installation of an incorrect engine oil drain valve, which resulted in damage to the valve during landing gear retraction and subsequent engine failure due to oil starvation. Contributing to the accident was the failure of maintenance personnel to comply with the Airworthiness Directive regarding the engine oil drain valve.

NTSB analysis

The pilot was conducting the airplane's first flight following an annual inspection. About 5 minutes after takeoff, the engine started to run rough and seized. The pilot performed a forced landing, during which he sustained serious injuries. Postaccident examination revealed that the engine oil drain valve was damaged when the nose landing gear contacted the valve during gear retraction after takeoff. This resulted in a loss of engine oil and subsequent engine failure due to oil starvation. Further examination revealed that the installed drain valve did not meet manufacturer specifications; the installed valve protruded about 1-1/8 inches from the engine, while the manufacturer-specified valve protruded about 1/2 inch. A review of the airplane maintenance records revealed that the valve was replaced during the annual inspection because it had been leaking.

The airframe manufacturer had previously issued a service bulletin regarding installation of an incorrect engine oil drain valve. The Federal Aviation Administration subsequently issued an Airworthiness Directive requiring the replacement of any incorrectly installed valves and placement of a warning placard on the engine mount. The airplane maintenance manual also included a cautionary note regarding the engine oil drain valve and noted the requirement for a warning placard. A warning placard was not present on the accident airplane.

Text from the NTSB. Open the NTSB docket for CEN19LA132 for the full record.