NTSB Factual Report

On July 17, 2000, at 1945 central daylight time, an Air Tractor AT-401 agricultural airplane, N6055W, was destroyed when it impacted terrain while maneuvering near Panhandle, Texas. The airplane was registered to and operated by Stamps Spraying Service, Inc., of Panhandle, Texas. The commercial pilot, sole occupant of the airplane, sustained fatal injuries. Visual meteorological conditions prevailed and a flight plan was not filed for the 14 Code of Federal Regulations (CFR) Part 137 aerial application flight. The local flight originated from the operator's private grass airstrip.

According to the operator, the airplane was fueled, loaded with an herbicide chemical, and departed to spray a field. When the pilot arrived at the field, he radioed back to the operator and stated that he was worried about chemical drift due to the wind speed and direction. A few minutes later, the pilot radioed the operator again and stated that he would commence spraying the field.

According to witnesses, the airplane was spraying chemical prior to the accident. One witness reported that the airplane was making a climbing turn and then nose dived into the ground. Another witness stated that he observed the airplane make one pass, initiate a "pull-up," and enter a right bank. He added that the airplane "did not pull out of the right bank and nose dived into the ground."

According to the FAA inspector and a representative from Air Tractor Inc., who examined the airplane at the site, the airplane came to rest at North 034 degrees 00.000 minutes latitude and West 068 degrees 54.375 minutes longitude. The engine and propeller were embedded within the initial impact crater, and the propeller blades exhibited "S" type bending. Two ground scars consistent with the shape of the leading edge of the wings were observed emanating outward from the crater. The cockpit and cabin area was destroyed by impact forces and the leading edges of both wings were compressed rearward to the main spar. Aileron control continuity was established from the control surface to the inboard section of each wing. Further continuity for the ailerons was precluded by impact damage to the fuselage and cockpit area. The empennage remained intact, although it sustained structural damage. Control continuity for the rudder was established from the rudder pedals to the control surface. Control continuity for the elevators was precluded due to impact damage, although continuity for the elevator trim system was established between the cockpit and the elevator trim tabs. An unidentified substance, which resembled pipe insulation, was installed between the elevators and the stabilizers as a gap seal. The flap actuator was located and the jackscrew was extended between 3.5 and 3.75 inches, which is consistent with the flaps being extended between 25 and 26 degrees.

According to data that was extracted from a SATLOC GPS unit, which was found at the accident site, the majority of turns had diameters measuring approximately 1,000 feet. The last turn recorded on the unit revealed that the airplane completed 230 degrees of a turn and the turn had a diameter of 660 feet. The data stops at a location near the accident site on a heading of approximately 280 degrees.

An autopsy was performed on the deceased pilot by the Lubbock County Medical Examiner's Office, Lubbock, Texas. Toxicological testing, performed by the FAA's Civil Aeromedical Institute, Oklahoma City, Oklahoma, revealed that there was putrefaction of the body and 50mg/dL, mg/hg of ethanol detected in the kidney, 10mg/dL, mg/hg of acetaldehyde detected in the kidney, and 1mg/dL, mg/hg detected in the kidney. The toxicological tests were negative for drugs.

NTSB Probable Cause

The pilot's failure to maintain airspeed, which resulted in a stall.