On July 26, 1999, at 1530 central daylight time, an Air Tractor AT-301 agricultural airplane, N4393S, registered to a private individual and operated by ANF Air Services of Garwood, Texas, was substantially damaged during a forced landing, following a loss of engine power near Victoria, Texas. The commercial pilot, sole occupant of the aircraft, was not injured. Visual meteorological conditions prevailed, and a flight plan was not filed for the 14 Code of Federal Regulations Part 137 aerial application flight. The local flight originated from the Victoria Regional Airport, Victoria, Texas. According to the FAA inspector, the aircraft was on its first swath run of a boll weevil eradication flight when the engine cowling separated from the aircraft. As the cowling separated it struck the engine and propeller. The engine lost power and the pilot executed a forced landing to a cotton field. During the landing roll, the aircraft "spun" around. Examination of the aircraft by an FAA inspector revealed that the right main landing gear was sheared off, and the left wing was pulled away from the fuselage. Further examination of the engine revealed that four push rod tubes were bent. According to the FAA inspector, the fractured engine cowling support bracket had a "dull surface like it had been broken for a while." The pilot and operator failed to return a completed Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1/2.