ANC05LA006

The commercial certificated flight instructor was giving flight instruction for a tailwheel endorsement to the commercial certificated airplane owner. Shortly after takeoff from the private airstrip, the airplane lost all engine power. The flight instructor assumed control of the airplane, and made a forced landing into adjacent trees. The airplane received structural damage to both wings and the rudder. Postaccident inspection of the airplane by an FAA airworthiness inspector disclosed that the airplane had completed an annual inspection about 9 flight hours prior to the accident flight. The inspector discovered that an incorrect size carburetor had been installed by the mechanic who did the annual inspection, and that the center fuel tank had corrosion and rust contamination, and was missing its outlet fuel screen. The inspector disassembled the fuel gascolator screen, and discovered it was clogged with foreign debris. After the gascolator was cleaned, the inspector reported that "the engine started and ran fine."

On October 13, 2004, about 1805 Alaska daylight time, a wheel equipped Piper J-3 airplane, N92469, received substantial damage when it collided with trees following a loss of engine power during the initial climb after takeoff from Wright Field, a private airstrip at North Pole, Alaska. The certificated flight instructor and the commercial pilot were not injured. The local instructional flight was operated under Title 14, CFR Part 91, by the airplane owner/commercial pilot. Visual meteorological conditions prevailed, and no flight plan was in effect.

During a telephone conversation with the NTSB investigator-in-charge (IIC) on October 14, the flight instructor related that he was giving instruction to the commercial pilot for a tailwheel endorsement. He related that he had observed the commercial pilot preflight the airplane, which included a check of the center fuel tank for water. He said they started the engine, warmed it up, and taxied to the opposite end of the field where a complete run-up was accomplished, and no anomalies noted. During the ensuing takeoff to the south, the instructor reported the commercial pilot allowed the airplane to drift slightly to the right, over the adjacent trees. About 200 feet above the ground (agl), he said the engine suddenly stopped running. Emergency procedures failed to restart the engine, and the instructor turned the airplane to the left, towards the runway. He was unable to complete the 180 degree turn without risk of stalling the airplane, and he elected to fly into the trees alongside the runway. The airplane received damage to the wings and fuselage during the collision.

An FAA inspector from the Fairbanks Flight Standards District Office traveled to the site on October 13 and 14, and interviewed both pilots and inspected the airplane. During an inspection of the engine's fuel system, he discovered that the fuel gascolator was contaminated with rust-like particulate matter and other foreign debris, effectively clogging the fuel outlet screen to the engine, and depriving the engine of fuel. He cleaned the gascolator screen, and the engine "started and ran fine." The inspector noted that the interior of the nose (center) fuel tank had some internal corrosion and debris, and that it was missing its outlet fuel screen. He also discovered that the engine was a C-90 Continental, but that a C-85 carburetor was installed. According to the inspector, the airplane was operating on aviation 100 octane low-lead fuel, and had undergone an annual inspection October 1, 2004, about nine flight hours prior to the accident. He reported that the aviation mechanic who conducted the annual inspection had also installed the incorrect size carburetor (C-85).