On August 15, 1995, at 0915 central daylight time, an Air Tractor, AT-400 operated by Walt's Flying Service, was destroyed when it impacted the terrain while maneuvering near Hayti, Missouri. The commercial pilot sustained fatal injuries. The aerial application flight departed a private airstrip near Cooter, Missouri, about 0905 and was conducted under 14 CFR Part 137 in visual meteorological conditions. No flight plan was filed. The wreckage was located 8.7 nautical miles northeast of Hayti, Missouri, on the Malden VOR 134 degree radial at 23.9 nautical miles. The soybean field, which the pilot was reportedly spraying was about 1/4 mile south of the accident site. Examination of the wreckage by a Federal Aviation Administration (FAA) airworthiness inspector revealed both wings remained attached to the fuselage and both leading edges were crushed aft to the spar at an angle corresponding to a pitch of approximately 90 degrees. All primary airframe components were identified at the site. The grass surrounding the propeller crater was cut in a circle which resembled the shape of a propeller arc. The propeller was "screwed" into the ground. A strong concentration of herbicide residue was below the instrument panel. The gas generator rpm gage was trapped at a reading of approximately 100 percent. The propeller rpm gage was trapped at 1900 rpm and the torque gage was trapped at about 600 foot pounds. Examination of flight and engine control continuity revealed no evidence of preimpact mechanical malfunction. The flap actuator was extended about 3/4 inch which, according to a representative of Air Tractor, corresponds to a flap position of five to ten degrees. During a personal interview, an agricultural pilot who had worked closely with the accident pilot, reported that the accident pilot would typically fly to a spraying site at 600 to 700 feet. He said the accident pilot would typically retard the engine torque to about 600 foot pounds to prevent excessive airspeed during the descent to the site and would subsequently need to add power during maneuvering. Autopsy of the pilot was conducted at the Mineral Area Regional Medical Center, Farmington, Missouri. FAA toxicological testing was negative for all tests conducted.