Incident Overview
While on a short final approach to land, the pilot noticed flames emanating from the left engine nacelle. He promptly shut off the fuel supply to the left engine and completed an uneventful landing. Following the landing, the fire continued to burn until the local fire department arrived and extinguished it.
Post-Accident Inspection
A post-accident inspection identified a leaking engine-driven fuel pump. The leak originated where the relief valve cover attaches to the fuel pump body. The screws securing the cover to the pump were found to be only finger tight. After the screws were re-tightened to the recommended torque values, the leak ceased.
Testing of Similar Fuel Pumps
Additional fuel pumps of the same type, which were new and had not been installed, were tested for leaks. Four out of seven pumps tested exhibited leaks. In each leaking pump, the relief valve cover screws were found to be undertorqued.
Historical Context and Service Bulletins
The fuel pump model in question has a documented history of leaks. Previously, service bulletins had been issued that called for inspection and refastening of the cover screws. The accident airplane was found to be in compliance with the applicable factory service bulletins. In response to the recurring issue, both the fuel pump manufacturer and the engine manufacturer have issued new service bulletins that mandate repetitive inspections of the fuel pump.