On October 14, 1999, at 1013 central daylight time, an Air Tractor AT-301 agricultural airplane, N23930, owned and operated by Burkett Flying Service of Sinton, Texas, nosed over during a forced landing following the in-flight separation of a portion of one propeller blade near Olton, Texas. The airplane sustained substantial damage, and the airline transport pilot, the sole occupant, received minor injuries. Visual meteorological conditions prevailed and no flight plan was filed for the 14 Code of Federal Regulations Part 137 local aerial application flight. The airplane departed from Littlefield, Texas, at 0820. According to the pilot and the FAA inspector, who conducted an on site examination, the airplane was applying insecticide to cotton crops as part of the federally sponsored boll weevil eradication program. The airplane began to shake violently, and the pilot executed a forced landing in a field. During the landing roll, the pilot applied the brakes to avoid colliding with an irrigation pipe, and the airplane nosed over and came to rest in the inverted position. The top of the vertical stabilizer and rudder were crushed. Additionally, the engine mount was damaged, and the engine cowling was missing. The propeller remained attached to the engine. One of the propeller blades was intact, and the other blade was separated approximately midspan. The separated section of blade was not recovered. The engine cowling was recovered approximately 3/4-mile from the accident site. A closer examination of the propeller, by another FAA inspector, revealed that it "appeared to have suffered damage caused by a wire strike; however, there were no broken high wires in the immediate area of the crash. The pilot did not recall striking any wires." The inspector stated that "it could not be determined whether the damage had occurred just prior to the blade failure or if it had been damaged and not properly repaired prior to operation."