LOS ANGELES, CA, USA
N41BF
DAVENPORT LONG-EZ
AFTER BEING CLEARED FOR A FLYBY, THE AIRCRAFT WAS OBSERVED OVER THE RUNWAY AT 20 TO 30 FEET AGL. A FEW SECONDS LATER, THE PILOT DECLARED AN ENGINE FAILURE. THE AIRCRAFT MADE A LEFT TURN SOUTHWEST OF THE AIRPORT STRIKING OVERHEAD ELECTRICAL LINES, SEVERING THE RIGHT WING, ROLLING RIGHT, AND CRASHING INTO A RESIDENCE. A POSTACCIDENT INSPECTION OF THE AIRCRAFT REVEALED THAT THE ELECTRIC FUEL BOOST PUMP AND THE MECHANICAL ENGINE- DRIVEN FUEL PUMP HAD BOTH BEEN REMOVED. THE DESIGNER HAD PREVIOUSLY TESTED A GRAVITY FUEL SYSTEM AND FOUND IT UNACCEPTABLE, SINCE THE HEIGHT OF THE FUEL TANKS ABOVE THE CARBURETOR DID NOT PROVIDE A SUFFICIENT FUEL PRESSURE. CONSTRUCTION PLANS STATED THAT THE FUEL SYSTEM IS 'DESIGNED TO REQUIRE TWO FUEL PUMPS', AND THAT THESE TWO FUEL PUMPS ARE A 'MANDATORY REQUIREMENT FOR SAFE OPERATION, AND THAT THERE IS NO ACCEPTABLE WAY AROUND THIS REQUIREMENT.' THE REQUIREMENT WAS REITERATED IN THE JULY, 1980, ISSUE OF THE CANARD PUSHER NEWSLETTER. THIS WAS THE FIRST FLIGHT FOLLOWING THE REMOVAL OF BOTH FUEL PUMPS BY THE PILOT/OWNER.
On May 7, 1995, at 1251 hours Pacific daylight time, a home built experimental Davenport Long-EZ, N41BF, was destroyed while attempting a forced landing at Los Angeles, California. The aircraft was owned and operated by the pilot and was on a local solo flight. Visual meteorological conditions prevailed and no flight plan was filed for the operation. The certificated private pilot sustained serious injuries. The flight originated from the Santa Monica Municipal Airport, Santa Monica, California, at 1247 on the day of the accident. After clearing the aircraft for takeoff, the tower operator reported that the pilot requested a flyby. He approved the request, and as the aircraft completed the traffic pattern, he observed it flying over runway 21 at an estimated 20 to 30 feet agl. A few seconds later, he reported receiving a radio transmission from the pilot declaring an engine failure. After the reported engine failure, the aircraft was observed making a left turn approximately 1/8-mile southwest of the airport. While in the turn, the aircraft struck overhead electrical transmission wires, severing the right wing. The aircraft then rolled right and crashed into the attached garage of a single-family residence. The aircraft came to rest in an inverted attitude, becoming wedged in the wooden garage structure. The pilot, who was unable to exit the aircraft, was extricated by emergency personnel. A postaccident inspection of the aircraft revealed that the electric fuel boost pump and the mechanical, engine-driven fuel pump had both been removed. According to the representatives of the designer, a gravity fed fuel system had been flight-tested and was found to be unacceptable, since the location of the fuel tanks did not provide a sufficient "head" of fuel above the carburetor bowl to maintain the necessary fuel pressure. The designer's construction plans state that the fuel system is "designed to require two fuel pumps", and that these two fuel pumps are a "mandatory requirement for safe operation, and that there is no acceptable way around this requirement." The requirement was reiterated in the July, 1980, issue of the Canard Pusher newsletter. This had reportedly been the first flight following the removal of both fuel pumps. Further examination of the fuel system revealed evidence that the fuel line between the gascolator and the carburetor had been stretched and kinked in the installation process. When inspected, the gascolator fuel screen exhibited the visible presence of contaminants. The carburetor fuel filter was clean and free of contamination. Fuel found trapped in the fuel lines had the color and odor consistent with auto fuel. The fuel lines from both the right and left tank sumps had been plumbed together using a "T" fitting. The "T" fitting had then been connected directly to the fuel selector valve. Each fuel tank had been individually vented with the vents positioned on either side of the aft canopy frame, over the inboard wing/fuel strake. The vents were mounted in what the designer described as a "low pressure" area, and had also been positioned flush with the skin of the aircraft. The designer's construction plans state that the fuel vents should be positioned facing and protruding into the slipstream. The engine crankshaft was rotated and continuity was established to the accessory gears. After removal of the No. 4 cylinder rocker box cover, valve action was also established. Thumb compression was obtained on all four cylinders. The engine contained oil, and the oil pressure screen was clean and free of contamination. The left magneto had been destroyed; however, the right magneto was removed and a spark was obtained from all four ignition leads. The No. 1 and 3 bottom spark plugs were removed and found to be wet with oil. The No. 4 spark plug was fouled with lead. A scotch brite pad was found installed as an air induction filter. The shoulder harness, which had been anchored to the front seat bulkhead, had separated. The designer's construction plans identify hard points; however, the builder had not utilized them in the shoulder harness installation. The designer's representative stated that the builder's method of installation would not provide adequate support for the accelerative loads imposed by the pilot's upper body during an impact.
fuel starvation due to a modification of the fuel system that rendered it incapable of maintaining adequate fuel pressure. The builder/pilot's lack of understanding of the fuel system was a factor in this accident.
Source: NTSB Aviation Accident Database
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