Incident Overview
A passenger aboard a twin-engine scheduled commuter airplane reported to the pilot that there was black smoke, fire, and oil coming from the left engine. The pilot immediately shut down the left engine, executed a 180-degree turn to return to the departure airport, and alerted emergency fire crews to standby for the return. Upon arrival, fire department personnel extinguished the fire.
Aircraft Information
The airplane was equipped with two Textron Lycoming TIO-540-J2BD engines.
Investigation Findings
A post-incident inspection revealed that the oil filter adapter plate gasket material displayed obvious signs of degradation and deformation. Subsequent investigation determined that the manufacturer supplying Textron Lycoming with the oil filter adapter plate gaskets had recently changed material suppliers. The new gasket material did not meet the existing specifications and deteriorated when in contact with hot engine oil. This deterioration led to a subsequent oil leak that sprayed engine oil within the engine cowling, near the rear of the engine, adjacent to the engine turbocharger.
Conclusion
The incident was attributed to the failure of the oil filter adapter plate gasket, which allowed engine oil to leak onto hot engine components, resulting in the observed smoke and fire.