HISTORY OF FLIGHT On May 3, 2010, at an undetermined time, an Aero Commander S2R, N5531X, was substantially damaged after impacting trees and terrain near DeWitt, Arkansas. The commercial pilot was fatally injured. The aerial application flight was registered to and operated by AufderHeide Flying Service, Inc. and being conducted under the provisions of 14 Code of Federal Regulations Part 137. Visual meteorological conditions prevailed at the time of the accident. The flight originated from De Witt Municipal Airport (5M1), De Witt, Arkansas, at 1530 central standard time (CST). There were no witnesses to the accident. According to the operator, the pilot departed 5M1 to conduct aerial application on two rice fields located about three miles south of 5M1. The fields were described as having thick woods on several sides. A search for the airplane began when the pilot did not return by 1630, his expected land time. The wreckage was located about 2030. PERSONNEL INFORMATION The pilot, age 51, held a commercial pilot certificate for airplane single-engine land, and a second class airman medical certificate issued January 15, 2010, with the limitation “Must have available glasses for near vision.” A review of the pilot’s log book indicated he had 8,257 total hours and approximately 650 hours in the make and model of the accident airplane. His last biannual flight review occurred on May 25, 2009. AIRCRAFT INFORMATION The single seat, low-wing, fixed gear airplane, serial number 1731R, was manufactured in 1973. It was powered by a Garrett TPE331-2-201A engine, serial number P-90252C, rated at 715 horsepower at 2,000 propeller revolutions per minute (RPM), equipped with a Hartzell HC-B3TN-5C 3-bladed propeller. The last airframe inspection was an annual type on December 12, 2009, at 10,231.2 total time airframe (TTAF). The last engine inspection was a 100-hour type on December 13, 2009, at 5,272.1 tachometer (TACH) time and 9,294.5 hours since new. The operator reported 10,350 hours TTAF at the time of the accident. METEOROLOGICAL INFORMATION A review of recorded data from the Stuttgart, Arkansas, (SGT) automated weather reporting station, about 15 miles northwest of the accident location, revealed at 1555 conditions were wind 230 degrees at 8 knots, visibility of 10 miles, and clear skies. WRECKAGE AND IMPACT INFORMATION The airplane impacted trees and terrain in a heavily wooded area on a southern heading. The left and right wings, the fuselage, and the empennage exhibited crushing and deformation. Flight control continuity could not be verified due to damage to the airplane. The outboard sections of two of the three propeller blades were separated and all three propeller blades exhibited twisting and leading edge damage. MEDICAL AND PATHOLOGICAL INFORMATION The Arkansas State Crime Laboratory, Medical Examiner Division, located in Little Rock, Arkansas, performed an autopsy on the pilot on May 5, 2010. The cause of death was attributed to blunt force injuries. The FAA, Toxicology Accident Research Laboratory, located in Oklahoma City, Oklahoma, conducted toxicological testing on the pilot. Testing for carbon monoxide, cyanide, and ethanol were negative. The following drug was detected: 4.786 (ug/ml, ug/g) Acetaminophen detected in blood. TESTS AND RESEARCH The propeller and propeller hub assembly were examined by Hartzell Propeller Inc. under the supervision of a Federal Aviation Administration (FAA) inspector. The spring retainer sleeve had multiple impact marks that occurred at different piston/blade angle positions. The spinner dome was separate from the main propeller assembly and was severely damaged and fragmented. The spinner bulkhead had multiple bends. The feather stop was intact. The tips of two propeller blades were separated and each blade had bending and twisting with leading edge damage. The engine was examined by individuals from Honeywell under the supervision of an FAA inspector. There was evidence of impact damage to the engine. The engine gear case was separated at the compressor inlet, the engine propeller shaft was not free to rotate, and the engine power section rotated with resistance. There was rotational scoring through 360 degrees on the propeller shaft immediately aft of the propeller shaft lock nut with corresponding rotational scoring damage on the forward inner bore of the sun gear. Rotational scoring was found through 360 degrees on the forward face of the propeller shaft roller bearing. Rotational scoring was present on the inside diameter of the compressor section mainshaft with corresponding rotational scoring damage on the High Speed Pinion (HSP)-to-power coupling shaft. Evidence of rotational scoring was also located on the first stage compressor impeller shroud surface and additional locations in the compressor section. There were metal spray deposits on the suction side of the first, second, and third stage turbine stator vanes and metal spray deposits on the suction side of the first and second stage turbine rotor blades. No pre-impact anomalies were noted with the engine. Within the gearbox section, there were four sets of witness marks, two witness marks per set with each set separated by 90 degrees, on the propeller shaft lock nut with corresponding metal transfer to two teeth of each planet gear. The ring gear retainers that were intact and in place exhibited witness marks consistent with the planet gear teeth profile. There was a witness mark on the forward face of the propeller pitch control housing corresponding to the locking clip on the propeller shaft. The engine fuel control unit, propeller governor, and P2T2 sensor were examined at Woodward Governor Company under the supervision of an FAA inspector. No preimpact anomalies were noted with any of the units.