Ulysses, KS, USA
N50669
Air Tractor AT-602
The pilot departed a private airstrip approximately 1 hour prior to the accident with approximately 140 gallons of fuel. He sprayed one field with a power setting of 80 gallons per hour fuel burn, then sprayed a second field with a power setting of 75 gallons per hour fuel burn. After spraying the second field, the pilot noted the fuel gauges indicated 1/4 fuel in the left tank, and 1/8 fuel in the right tank. He turned on the fuel boost pump and sprayed passes on the west end of the field using a back to back pattern, running north and south with right and left turns. The last pass was to the north. He pulled up over power lines and turned right (downwind) for the local airstrip located 3 miles away. The engine lost power, and the pilot attempted a restart. The engine started "for a second" and then lost power again. The pilot then landed straight ahead, downwind, in a hilly corn field. The airplane impacted a ditch at the end of the field collapsing the main landing gear. Examination of the airframe revealed the fuselage and firewall were buckled. An airframe manufacturer's service letter provided guidance to the Owner/Operator in preventing and/or minimizing the imbalance of the fuel level between the left and right main fuel tanks, which could lead to fuel starvation if one tank goes dry. The fuel imbalance can result from migration of fuel from one tank to the other, or uneven fuel flow to the header tank.
The pilot departed a private airstrip approximately 1 hour prior to the accident with approximately 140 gallons of fuel. He sprayed one field with a power setting of 80 gallons per hour fuel burn, then sprayed a second field with a power setting of 75 gallons per hour fuel burn. After spraying the second field, the pilot noted the fuel gauges indicated 1/4 fuel in the left tank, and 1/8 fuel in the right tank. He turned on the fuel boost pump and sprayed passes on the west end of the field using a back to back pattern, running north and south with right and left turns. The last pass was to the north. He pulled up over power lines and turned right (downwind) for the local airstrip located 3 miles away. The engine lost power, and the pilot attempted a restart. The engine started "for a second" and then lost power again. The pilot then landed straight ahead, downwind, in a hilly corn field. The airplane impacted a ditch at the end of the field collapsing the main landing gear. Examination of the airframe revealed the fuselage and firewall were buckled. The pilot sustained minor injuries. According to the pilot's statement, he listed the following recommendations: "A. Most of all I think Air Tractor has a problem with their fuel delivery system. No way should an aircraft starve for fuel with 10 gallons of fuel on board let alone 30-40 gallons. They may need a larger header tank, fuel pumps located differently, fuel tank pickups redesigned, or a way of venting air; I don't know. I have heard from other operators that this is not an uncommon problem. B. I should have, in retrospect, carried more fuel. C. I should have made myself aware of all service letters concerning this aircraft." According to the airframe manufacturer's service letter #178, "Imbalance of Fuel in Fuel Tanks", "This Service Letter is to provide guidance to the Owner/Operator in preventing and/or minimizing the imbalance of the fuel level between the left and right main fuel tanks, which could lead to fuel starvation if one tank goes dry. The fuel imbalance can result from migration of fuel from one tank to the other, or uneven fuel flow to the header tank."
the loss of engine power due to fuel starvation. A contributing factor was the impact with a ditch during the forced landing.
Source: NTSB Aviation Accident Database
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