History of Flight
On August 20, 2011, at about 1139 mountain daylight time, a Piper PA-25-235 airplane, N7051Z, was substantially damaged when it impacted terrain after conducting aerial application work about 5 miles north-northeast of Whitewood, South Dakota. The pilot was fatally injured. The airplane was registered to and operated by a private individual. The agricultural application flight was conducted under 14 Code of Federal Regulations Part 137. Visual meteorological conditions prevailed, and the flight was not operated on a flight plan. The local flight originated from Sturgis Municipal Airport (49B) about 1030 and was intending to return to Belle Fourche Municipal Airport (EFC) after the work.
According to the airplane owner, the pilot was applying insecticide to an alfalfa field about 12 miles north of 49B. The airplane was fueled the night prior. The pilot had relocated the airplane from EFC to 49B and completed three application flights without incident before the accident flight. The initial flight carried about 100 gallons of water/chemical mixture and a full fuel load of 65 gallons. The final flight was to complete the application; it carried about 30 gallons of mixture and about 30 gallons of fuel remained onboard.
A witness about two miles south of the alfalfa field reported observing the accident airplane conducting application work. She heard the engine and noted everything appeared normal. About 1100, she saw the airplane depart toward the east, in the general direction of the hill where it crashed. The airplane impacted a hillside along the east side of a valley. The land owner located the wreckage about 1139.
Personnel Information
The pilot held a commercial pilot certificate with single-engine land airplane, instrument airplane, and helicopter ratings. The helicopter rating was limited to private pilot privileges. He was issued a second-class airman medical certificate on January 13, 2011, with a limitation for corrective lenses. On that application, he reported a total flight time of 4,831 hours, with 78 hours flown within the previous 6 months. His logbook included a flight review endorsement dated August 1, 2009, with the previous review dated May 3, 2003. The logbook showed a total of 4,153 hours subsequent to a flight review entry dated June 1, 1998.
Aircraft Information
The accident airplane was a 1964 Piper PA-25-235 Pawnee, serial number 25-2819. It was a single-engine, tailwheel-equipped airplane, certificated in the restricted-agriculture/pest control category. The airframe had accumulated approximately 7,503 total flight hours. It was powered by a 235-horsepower Lycoming O-540-B2B5 engine, serial number L-8497-40, which had accumulated about 6,908 hours total time, with about 1,454 hours since overhaul. The most recent annual inspection was completed on June 1, 2011, at 7,382 hours total airframe time. No entries were made subsequent to that inspection.
Meteorological Information
Weather conditions recorded at 1135 by the Black Hills Airport Automated Weather Observing System, about 10 miles west-southwest of the accident site, were: wind calm, 10 miles visibility, clear sky, temperature 21°C, dew point 9°C, altimeter 30.15 inches of mercury.
Wreckage and Impact Information
The airplane impacted a hill along the east side of a valley. The impact point was about 14 feet below the crest of the hill, which led to a plateau extending east. The airplane came to rest about 250 feet from the initial impact point. The impact path and airplane were oriented on a northeast bearing.
The airplane came to rest on its right side. Both wings were deformed and partially separated from the fuselage. The empennage remained attached, but the right horizontal stabilizer was crushed consistent with ground impact. Flight control surfaces remained attached. The engine and propeller remained attached. One propeller blade was twisted with a portion of the tip separated; the second blade was curled aft over about the outboard one-half of its span. A section of propeller blade was recovered about 100 yards north of the main wreckage. The landing gear had separated and was located about 115 feet from the main wreckage.
A postaccident examination of the airplane, including flight controls and engine assembly, revealed no anomalies consistent with a preimpact failure or malfunction.
Medical and Pathological Information
An autopsy performed on August 22, 2011, attributed the pilot's death to traumatic injuries sustained in the accident. The FAA Civil Aerospace Medical Institute toxicology report detected 12% carbon monoxide in blood; no cyanide or ethanol; atorvastatin was detected in the liver but not in blood. Atorvastatin is a prescription medication commonly used to treat lipid disorders.
Additional Information
A handheld GPS receiver recovered from the airplane indicated five flights on the day of the accident. The first flight departed EFC about 0703, arriving at 49B about 0725. Four subsequent application flights departed 49B at about 0738, 0835, 0949, and 1037. GPS data showed the airplane proceeded northwest about 11 miles and made multiple passes in a local area before returning to 49B. The accident site was at the south end of that area. The accident flight departed 49B about 1037, and GPS data ended at 1046:57 shortly after turning from a northwest to a northerly course toward the application area. The final data point was about 0.3 miles south-southwest of the accident site.