AUBURN, CA, USA
N8597A
Beech A35
The airplane's engine lost power during the initial climb after departure, and the pilot performed a 180-degree turn back towards the airport, but landed short of the runway. The airplane was equipped with a hand operated emergency fuel pump, which was part of the fuel selector valve. The emergency procedures section of the POH states that the emergency hand pump should be used to restore fuel pressure in the event of an engine driven pump failure. The pilot stated that he never attempted to use the emergency hand fuel pump. An on-scene examination revealed fuel in both main tanks. Examination of the engine driven Lear-Romec fuel pump coupling found it had sheared and separated. Internal examination of the pump revealed bluing of the steel pump vane tips and galling of the pump liner. According to the manufacturer, the pump at some time had been operated without fuel, which cools the vanes, and had overheated. Metallurgical examination of the failed fuel pump coupling revealed that it separated due to ductile torsional overstress at a designed location. According to records available, the pump had accumulated about 619 hours since overhaul with an unknown total time.
HISTORY OF FLIGHT On March 17, 1998, about 1345 hours Pacific standard time, a Beech A35, N8597A, was substantially damaged during a forced landing following a loss of engine power during the takeoff initial climb at Auburn, California. The private pilot, who was the sole occupant, received minor injuries. Visual meteorological conditions prevailed for the personal flight, which had originated at Byron, California, made a stop at Auburn, and was returning to Byron. The pilot was operating the airplane under the provisions of 14 CFR Part 91 and no flight plan was filed. The flight was originating at the time of the accident. In an oral statement the pilot reported that during departure from runway 07 he lost engine power. He stated that he did not attempt to use the hand operated emergency fuel pump, and that he had just bought fuel at Auburn. He attempted a 180-degree turn back to the runway, extended the landing gear, but landed short of the runway. PERSONNEL INFORMATION The private pilot reported a total flight time of 330 hours at his December 5, 1997, third-class flight physical. He did not file a Pilot/Operator Aircraft Accident Report, form 6120.1/2; however, numerous requests were made from the Safety Board. AIRCRAFT INFORMATION According to logbook information, the aircraft received an annual inspection on March 4, 1998. At the time of the on-scene examination of the aircraft, the recording tachometer indicated 5.1 hours had elapsed since the inspection. After arriving at Auburn the pilot purchased 12.1 gallons of 100LL aviation fuel, the amount used from Byron to Auburn. He stated that he would routinely keep the wing tip tanks empty and the mains full. The aircraft is equipped with a hand operated emergency fuel pump, which is part of the fuel selector valve. The emergency procedures section of the Pilot Operating Handbook for the Beech A35 states that the emergency hand pump should be used to restore fuel pressure in the event of an engine driven pump failure. TESTING AND RESEARCH The on-scene examination revealed that fuel was present in the main tanks. All fuel system screens were found to have varying degrees of contaminates. The Lear-Romec RD 7790 engine driven fuel pump splined drive coupling was found sheared and separated. The emergency locator beacon did not work, and the BNC antenna connector was found disconnected. Both muffler cones were missing. While unrelated to the fuel system or engine, other discrepancies were found with components that are part of the manufacturer's recommended annual inspection checklist. The fuel pump was taken to a Federal Aviation Administration approved repair station for functional testing with a substitute coupling. However, due to the rotational resistance, the substitute coupling was at risk for failure and the test was discontinued. The fuel pump was sent to the manufacturer in Elyria, Ohio, for examination and testing under the supervision of the Federal Aviation Administration. According to the manufacturer's report, severe heat related bluing was noted on the blade tips. Additionally, the pump liner exhibited scoring, gauling, and metal transfer to the pump liner, increasing the operational torque and binding. According to the manufacturer, engine fuel is the normal cooling source to prevent heat and subsequent failure due to rotational resistance and binding. The failed fuel pump coupling was sent to the Safety Board's Materials Laboratory for failure analysis. According to the report, the coupling separated due to ductile torsional overstress at a designed location. According to records available, the pump had accumulated about 619 hours since overhaul with an unknown total time.
failure of the engine driven fuel pump drive coupling and the pilot's failure to perform the emergency procedure specified in the Pilot Operating Handbook.
Source: NTSB Aviation Accident Database
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