FTW97LA321

During the aerial application flight, the engine of the agricultural airplane lost power, and the pilot executed a forced landing in a cotton field. During the ground roll across the furrows in the field, the left main wheel separated from the landing gear leg, and subsequently, the right main landing gear leg separated from the fuselage. Examination of the engine revealed that a blade failure at the compressor turbine disk had occurred resulting in extensive damage to the hot section of the engine and the complete loss of engine power.

On August 25, 1997, approximately 1230 central daylight time, an Air Tractor AT-400 agricultural airplane, N3654G, registered to and operated by King Ag Aviation, sustained substantial damage during a forced landing following a loss of engine power near Sudan, Texas. The commercial pilot, the sole occupant, was not injured. No flight plan was filed and visual meteorological conditions prevailed for the Title 14 CFR Part 137 local aerial application flight.

In a written statement provided to the investigator-in-charge, the pilot reported that "the motor blew up," and he was forced to land the airplane in a field "going across" the furrows. During the ground roll, the left main wheel separated from the landing gear leg, the airplane "got sideways," and the right main landing gear leg then separated from the fuselage.

The FAA inspector who examined the accident site reported that the airplane touched down in a cotton field and rolled about 400 to 500 feet across the furrows before coming to rest in an upright position. He further reported that the fuselage forward of the tail section was twisted.

On September 9, 1997, the engine, a Pratt & Whitney PT6A-20, S/N PCE 22438, was examined under the supervision of a FAA inspector at Dallas Airmotive, Inc., in Dallas, Texas. According to the FAA inspector, "the engine experienced blade failure at the Compressor Turbine disk" resulting in "extensive damage to the hot section of the engine." The inspector reported that his review of the engine maintenance records indicated the blades had 11,381.6 hours total time in service. He further reported that "the blades still had some time left in accordance with the manufacturer's specifications."