Aviation Accident Summaries

Aviation Accident Summary ANC99LA033

FAIRBANKS, AK, USA

Aircraft #1

N4721U

Cessna 180G

Analysis

The certificated commercial pilot pushed the airplane out of a hanger and sumped the wing fuel tanks. The airplane remained outside throughout the day while the ambient temperature warmed. No further sumping of the wing tanks was conducted. After departure, the pilot reduced the engine power to level the airplane at the airport traffic pattern altitude. The engine began to run rough, and the pilot began an emergency landing approach to a snow-covered airstrip located near the approach end of an asphalt runway. The engine roughness diminished, and the pilot was cleared to land on the larger asphalt runway. The engine then quit. The airplane touched down in an area of snow between the end of the small airstrip and the beginning of the asphalt runway. The airplane nosed over, and received damage to the vertical stabilizer, the rudder, and the left wing lift strut. An examination of the airplane revealed a wrinkle in the left wing fuel bladder, and 3 ounces of water in the gascolator.

Factual Information

On March 14, 1999, about 1828 Alaska standard time, a wheel equipped Cessna 180G airplane, N4721U, sustained substantial damage during an emergency landing at the Fairbanks International Airport, Fairbanks, Alaska. The airplane was being operated as a visual flight rules (VFR) local area personal flight when the accident occurred. The airplane was registered to, and operated by, the pilot. The certificated commercial pilot, the sole occupant, was not injured. Visual meteorological conditions prevailed. The flight originated at the Fairbanks Airport at 1825. During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), on March 15, 1999, at 1115, the pilot reported that after departure, he reduced engine power to level the airplane at 1,500 feet, which is the airport traffic pattern altitude. The engine began to run rough, and he began an emergency landing approach to the ski strip, runway 01 at the Fairbanks airport. The ski strip, 01/19, is a gravel surface runway 3,978 feet long and 75 feet wide, and is oriented on the same magnetic heading as runway 01R/19L. There is no lateral displacement between the two runways. The departure end of the ski strip 01 is displaced directly south of the approach end of runway 01R about 650 feet, and is intersected by taxiway B. The pilot said the engine roughness diminished, and he was cleared to land on runway 01R. The pilot said the engine then quit. The airplane touched down in an area of snow between the end of the ski strip 01, and the approach end of runway 01R. The airplane then nosed over, and received damage to the vertical stabilizer, the rudder, and the left wing lift strut. A Federal Aviation Administration (FAA) airworthiness inspector with the Fairbanks Flight Standards District Office (FSDO) examined the airplane on March 28, 1999, and interviewed the pilot. The inspector reported the pilot pushed the airplane out of a hanger, and sumped the wing fuel tanks. The airplane remained outside, and the ambient temperature warmed throughout the day. The pilot did not re-sump the airplane before departing. The inspector's examination of the airplane revealed a longitudinal wrinkle in the left wing fuel bladder. The wrinkle was positioned near the wing sump drain. The inspector also found about 3 ounces of water in the airframe gascolator.

Probable Cause and Findings

Water contamination of the fuel supply, and the pilot's inadequate preflight inspection to ensure all water was removed from the fuel supply. Factors in the accident were a wrinkle in the wing fuel tank bladder, and snow covered terrain.

 

Source: NTSB Aviation Accident Database

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