Aviation Accident Summaries

Aviation Accident Summary ATL05LA046

Bainbridge, GA, USA

Aircraft #1

N90772

Air Tractor AT-402A

Analysis

On the day of the accident, the pilot operated the airplane in eight or nine flights, each lasting approximately 45 minutes in duration. The pilot refueled the airplane from a refueling tank kept at his private airstrip before the first flight of the day. On the last flight of the day, after spraying a field, the pilot noticed a gradual loss of engine power and the airplane began to lose altitude. The airplane collided with trees and the ground 1/2 mile from the approach end of runway 36. Post-accident examination of the turbine engine and the fuel control unit revealed no abnormalities. The right wing fuel tank contained approximately six gallons of Jet-A straw colored fuel and the left wing fuel tank contained approximately one quart of water. The inner web of both left and right tanks were punctured. There was no fuel recovered from the header tank and the fuel filter had fuel located in the bowl. The engine fuel filter appeared dirty and fuel in the bowl appeared discolored. The fuel last chance filter appeared clean with a small amount of fine particles in the engine bowl. The AT-402A has a fuel capacity of 167 gallons of usable fuel and three gallons of unusable fuel.

Factual Information

On January 12, 2005, at 1500 Eastern Standard Time, N90772, an Air Tractor AT-402A agricultural airplane, collided with trees and the ground following a loss of engine power 500 feet from runway 36 at Brock Air Park, Bainbridge, Georgia. The aerial application flight was conducted under the provisions of 14 CFR Part 137, and visual flight rules. Visual meteorological conditions prevailed at the time of the accident, and no flight plan was filed. The commercial pilot was not injured and the airplane sustained substantial damage. The flight originated at Brock Air Park, a private airstrip in Bainbridge, Georgia at 1415. According to the pilot, on the day of the accident, he operated the airplane during eight or nine flights, each lasting approximately 45 minutes in duration. He stated that he fueled the airplane from a refueling tank kept at his private airstrip before his first flight of the day. He stated that after spraying a field on the last flight of the day, he noticed a gradual loss of engine power, and the airplane began to lose altitude. The pilot increased propeller pitch to full, turned the electric fuel boost pump on, and made continuously unsuccessful attempts to restart the engine. The pilot determined that he would not be able to land on the runway, so he made a forced landing into a field of pine trees. The airplane collided with trees and the ground about 1/2 mile from the approach end of runway 36. Post-accident examination of the wreckage site revealed the airplane rested in a wooded area in a right wing low attitude and aligned along a 030 degree magnetic heading. Post-accident examination of the airplane revealed the right wing was partially separated from the fuselage at the wing root and the right wing spar was bent aft. The left wing was separated from the fuselage at the wing root. The fuselage structure and the landing gear were intact. Post-accident examination of the engine revealed that the turbine blades had slight rub marks at the hub. The exhaust area was crushed and buckled. Debris was observed in the exhaust area. Engine control continuity was established from the cockpit power quadrant to engine power controls. The engine also displayed light rotational contact signatures to its internal components. The gas generator rotated freely. The P-3 pneumatic air filter was clean and free of debris. The oil filter was clean and free of debris. The electric fuel pump provided fuel flow during the functional test. The three-blade propeller had one tip sheared, one tip bent aft, and one blade bent aft near the hub. Post-accident examination of the fuel control unit filter revealed that it was clean and free of debris and contained approximately two cups of fuel. The airframe fuel filter was clean and free of debris and contained approximately one cup of fuel. The right wing fuel tank contained approximately six gallons of Jet-A straw colored fuel, and the left wing fuel tank contained approximately one quart of water. The inner web of both left and right tanks were punctured. There was no fuel recovered from the header tank and the fuel filter had fuel located in the bowl. The engine fuel filter appeared to contain dirty and the fuel in the bowl appeared discolored. The fuel last chance filter appeared clean with a small amount of fine particles in the engine bowl. The airplane did not have the optional Emergency Fuel Control Override installed. According to witnesses, light rain showers were prevalent in the area on the evening of the accident. According to a Air Tractor representative, the AT-402A has a fuel capacity of 167 gallons of usable fuel and three gallons of unusable fuel. Post examination of the fuel control unit included a functional test preformed by Pratt and Whitney Canada, which determined no conditions that would preclude full engine control and full power being available. Laboratory examination of the low fuel warning light, fuel filter bypass warning light, air filter bypass warning light, chip detector warning light, and propeller in beta range light filaments were not stretched.

Probable Cause and Findings

The pilot's inadequate management of the fuel supply, which resulted in fuel starvation.

 

Source: NTSB Aviation Accident Database

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