Accident Details
During a cargo flight to Concord Regional Airport in North Carolina, the pilot reported that at an altitude of approximately 2000 feet and 5 miles from runway 20, the engine began to lose power. The pilot switched from the left main tank to the right main tank, which briefly restored engine power. However, power then decreased again to 1000 rpm. The pilot subsequently switched from the right main tank to the auxiliary tip tanks, but noted no increase in engine power. The pilot contacted the Concord Regional Airport tower and informed them that the airplane was "going down." The airplane collided into a rock quarry approximately one mile from the approach end of runway 20.
Fuel Pump Examination
Post-accident examination of the airplane revealed that the engine was displaced aft. Examination of the fuel pump (model RG17980D/M, serial number B-4766-3402) disclosed that the unit had been repaired in the field during its life. The fuel pump was shipped new prior to 1989, and no record of overhaul or upgrade activity by the manufacturer was noted. Additionally, no evidence of preventive maintenance was found. Examination of the fuel pump revealed severe wear to the rotor interface with the drive coupling, rubber seal material worn on the rubber journal, and severe wear to the rotor seal. The inside diameter of the rotor seal was severely oversized, compromising the sealing capability at the pump's drive end. This location exhibited extensive leakage during testing.