Accident Details
Shortly after takeoff, at about 150 feet above ground level, the engine suddenly lost power. The pilot was unable to restart the engine and turned the aircraft toward a clearing. The aircraft stalled just before colliding with trees and subsequently the ground.
Examination Findings
During the engine examination, it was found that the engine-driven fuel pump was loose at the base of the pump, and the splined shaft of the pump was not properly engaged. The drive pin was not properly engaged, and the snap ring securing the seal spring retainer and spring from extending beyond the end of the shaft was not secured around the end of the rotor. A section from the end of the rotor was broken off.
Metallurgical Examination
Metallurgical examination of the fuel pump components revealed that the seal spring retainer snap ring was severely worn. When assembled in place on the rotor, it would barely keep the seal spring retainer on the shaft end of the rotor. The rotor fracture was typical of overstress.
Mechanic's Report
The mechanic who last inspected the fuel pump reported that during the inspection of the fuel pump drive pin, he did not disassemble the components as indicated in the accomplishment instructions of a service letter by the engine manufacturer that he was using, nor the Service Bulletin published by the fuel pump manufacturer. The mechanic reported that he did not remove the snap ring to gain access to the drive pin for the drive pin inspection, nor did he replace any of the fuel pump components. The Service Bulletin, in a note under assembly of the pump, states to not reuse the snap ring.