Anchorage, AK, USA
N2914M
Piper PA-12
On the takeoff initial climb, about 60 feet above the ground, the airplane's engine lost power. During an emergency descent/ landing, the pilot said he switched the fuel selector valve from one tank to the other. During the landing roll, the engine power suddenly returned. The right main landing gear tire struck a runway edge light fixture, and the right main gear collapsed, damaging the propeller and the right wing lift strut. During recent maintenance, a mechanic had removed the fuel selector valve for lubrication and inspection. The mechanic reported that he noticed the fuel valve shaft did not have an index shape to properly match the selector handle position, and consequently was careful to reinstall the handle on the valve as he found it. The mechanic performed about a 10 minute engine run after reinstalling the valve. He said the pilot also ran the engine for about an additional 10 minutes before departure. The fuel selector handle is attached to the valve shaft by a screw, and can be rotated 360 degrees. The handle incorporates an arrow to provide visual reference for fuel tank selection that matches placard markings on a metal trim panel. An examination of the airplane was conducted at a recovery facility by FAA personnel, 18 days after the accident. Prior to the examination, the fuel valve handle and trim panel were removed by recovery personnel, but reportedly replaced in the position found before recovery. The FAA found that the selector handle was installed with the arrow of the handle oriented 90 degrees counterclockwise from its proper valve orientation. When the fuel selector handle was placed on the left tank, the valve was actually positioned to the right tank. When the fuel selector handle was placed on the right tank, the valve was actually positioned to an "off" position. The pilot initially reported that the fuel selector handle was positioned on the left tank during takeoff, but when asked later about the fuel selector handle position, he said he could not be certain that the fuel handle was on the left fuel tank. No further examination of the airframe fuel system or the engine was performed.
On September 29, 2003, about 1400 Alaska daylight time, a tundra tire-equipped Piper PA-12 airplane, N2914M, sustained substantial damage when the right main landing gear collapsed during an emergency landing, following a loss of engine power on takeoff, at Merrill Field, Anchorage, Alaska. The airplane was being operated as a visual flight rules (VFR) local area personal flight under Title 14, CFR Part 91, when the accident occurred. The airplane was operated by the pilot. The commercial certificated pilot, the sole occupant, was not injured. Visual meteorological conditions prevailed. No flight plan was filed, nor was one required. During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), on September 30, the pilot reported he was relocating the airplane from Merrill Field to the Lake Hood Strip, Anchorage. He reported the fuel selector handle was positioned on the left tank. The left tank contained about 12 gallons of fuel, and the right tank contained about 10 gallons. The pilot said that after departing runway 33 at Merrill Field, and about 60 feet above the ground as he was beginning a left turn, the engine suddenly "quit." The pilot turned to the right, toward the airport, and the airplane touched down along the right edge of the remaining runway, near the intersection of runway 33 and runway 06. Due to landing traffic on runway 06, the pilot decided to allow the airplane to roll off the pavement into a grass area. During the emergency landing roll, the right main landing gear tire struck a runway edge light fixture. The right main gear collapsed and damaged the right wing lift strut. The airplane nosed down and received additional damage to the propeller and engine cowling. In a telephone conversation with the pilot on March 5, 2004, the pilot further clarified some details of the accident. During the emergency descent/landing, he switched the fuel valve from one tank to the other. He said he recalled that during the emergency landing roll, the engine power suddenly returned, which contributed to his departure off the runway surface. When questioned about his recollection about the fuel selector handle position during takeoff, he said he could not be 100 percent certain that the fuel handle was on the left fuel tank. The pilot reported that the airplane's annual inspection was valid until September 30. Before the accident, an annual inspection had been started, but not completed by an aviation mechanic. During the annual inspection process, the mechanic had removed the fuel selector assembly for lubrication and inspection, and then reinstalled the fuel valve and valve handle. During a telephone conversation with the NTSB IIC on March 24, 2004, the mechanic who performed the valve maintenance reported that he began an annual inspection on the accident airplane using an inspection worksheet. He discovered the fuel valve was stiff. He said he removed the valve handle and noticed that the valve shaft did not have a spline or "doghouse" shape to match the handle shape for proper position indexing. Because the valve did not have an index, he said he was careful to reinstall the handle as he found it, after servicing the valve. The mechanic indicated that he then performed an engine run for about 10 minutes. He said he was not certain what fuel tank position the handle was indicating; however, he remembered switching tanks during the engine run by moving the handle from what he thought was about a 12 o'clock to about a 3 o'clock position. The mechanic also said that prior to departing on the accident flight, the pilot performed an additional engine run for about 10 to 15 minutes. The underside of the airplane's fuel selector handle has a mounting flange that mates to the shaft of the fuel selector valve, and is held in place by a screw. The valve can be rotated 360 degrees through 4 detents. The handle incorporates an arrow pointer to provide visual indication of valve position at each detent, corresponding to placard markings on a metal trim panel. Two valve positions are left and right. The remaining two detents, at 3 o'clock and 6 o'clock positions, are "off" positions. The airplane engine's gravity-fed fuel supply flows from the wing mounted fuel tanks, through respective header tanks, to the fuel selector valve, to the airframe mounted gascolator, and then to the carburetor. The left fuel tank has a 2 quart header tank located forward of the instrument panel. A 2 quart header tank for the right fuel tank is located behind the headliner, aft of the rear seat. The header tanks serve to maintain constant fuel flow to the engine during maneuvering flight. An FAA Aviation Safety Inspector examined the airplane on October 17, 2003, at a recovery facility. The FAA inspector reported that the wings were in a back room of the facility, and the fuselage was resting on a trailer. Prior to the examination, recovery personnel told the FAA inspector that air pressure was applied to the exposed fuel lines in the wing root area of the fuselage. This test revealed that when the fuel selector handle was placed on the left tank, the valve was actually positioned to the right tank. When the fuel selector handle was placed on the right tank, the valve was actually positioned to an "off" position. Also, prior to the FAA's examination, recovery personnel removed the fuel selector handle from the fuel valve, along with interior trim panels, to gain access to the valve body, but reportedly replaced the handle on the valve in the position found, prior to recovery. Recovery personnel provided a signed diagram to the FAA regarding their testing of the valve position. The FAA inspector examined the mounting flange on the underside of the valve handle, and verified that its design incorporated a rounded or domed shape on one of the four sides of the flange. This rounded shape would normally index with a similar shape of the fuel valve shaft. The FAA inspector indicated that the shaft of the accident airplane's fuel valve was square, and the selector handle was installed with the arrow portion of the handle oriented 90 degrees counterclockwise from its proper orientation. No further examination of the airframe fuel system or the engine was performed.
A loss of engine power for an undetermined reason, which resulted in a forced landing and collision with a runway light fixture.
Source: NTSB Aviation Accident Database
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