Accident Overview
On May 30, 2018, about 1710 central daylight time, an Ayres Corporation S2R-T34 airplane, registration N2249B, impacted guy wires and terrain near El Reno, Oklahoma. The commercial pilot was fatally injured, and the airplane was destroyed by postimpact fire. The airplane was operated by Andy Deterding Ag Aviation as a Title 14 Code of Federal Regulations Part 137 aerial application flight. Day visual meteorological conditions prevailed, and no flight plan was filed. The flight originated at Medford Municipal Airport (O53), Medford, Oklahoma, about 1600.
Witness Accounts
Two witnesses reported hearing an airplane flying low over their house just after 1700. They observed the airplane fly over a field about half a mile to the north. One witness saw the airplane make a tight turn, as if the pilot was attempting to avoid a radio tower guy wire, and noted the pilot appeared to be pulling up. The airplane's nose then pitched up and immediately descended toward the ground.
Pilot Information
The pilot held a commercial pilot certificate with an airplane single-engine land rating. According to his most recent Federal Aviation Administration (FAA) second-class medical certificate application, dated March 5, 2018, he had accumulated about 1,500 total flight hours, with 250 hours in the previous 6 months. The medical certificate required corrective lenses.
The pilot's son, who was the operator's chief pilot, stated that the pilot began flying between 0900 and 0930 on the day of the accident, took a 1-hour lunch break around 1300, and continued flying afterward. The pilot departed for his last load to El Reno about 1600. The airplane had a full fuel load and a light chemical load. The tower was depicted on the field map the pilot used for spraying, and the pilot had flown aerial application flights over that field for several years. He was expected to return to a grass strip in Carrier, Oklahoma, to reload if time permitted. Typically, the pilot would fly until about 1900, approximately 2 hours before dark.
Aircraft Information
The yellow, single-seat, low-wing, fixed-gear airplane was manufactured in 1997 and designed for aerial agricultural application. It was powered by a Pratt and Whitney PT6A-34AG turboprop engine, serial number PH1063, and equipped with a Hartzell HC-B3TN-3D/T10282N+4 four-bladed propeller. The most recent annual inspection was completed on April 3, 2018, at 6,843.4 total airframe hours. The engine was installed as factory new on that date with zero time. Maintenance records indicated a final inspection and engine run were completed before returning the airplane to service.
Meteorological Conditions
The 1555 recorded weather observation at Clarence E. Page Municipal Airport (RCE), Oklahoma City, Oklahoma, 8 miles south-southeast of the accident site, included wind from 140° at 12 knots, 10 miles visibility, few clouds at 5,500 feet, temperature 35°C, dew point 21°C, and barometric altimeter 29.70 inches of mercury. The National Oceanic and Atmospheric Administration solar position calculator indicated that at 1710, the sun's altitude was 40.07° and azimuth 269.89°. The airplane was flying from west to east at the time of the accident.
Wreckage and Impact
The airplane impacted the ground about 200 feet east of the wires at the edge of a ravine and came to rest inverted. The nose section, fuselage, empennage, and landing gear were consumed by postcrash fire. About 1 foot of the outboard section of a propeller blade was missing and was found in the field north of the main wreckage. A piece of the lower cowling and adjoining air scoop displayed damage consistent with impacting a guy wire. Both pieces were detached and lying closest to the fallen guy wires. About 25% of the outboard left wing was not fire damaged and exhibited leading edge and wingtip crushing. The right wing had thermal damage to half its inboard section with leading edge crushing. Flight control continuity was established from all surfaces to the cockpit, but continuity to the control stick could not be verified due to thermal damage.
The propeller assembly and engine were impact separated. Propeller blades showed bending, one fractured tip, and impact damage. The exhaust duct exhibited compression bending from guy wire contact and terrain impact, with some torsional bending. The engine separated at the "C" flange. Rotational scoring was observed on the compressor turbine disc and blades and the power turbine disc and blades, consistent with the engine producing power at impact.
The top and middle guy wires displayed yellow paint transfers at about the 155-foot mark from the ground attachment. Based on the paint transfer location and the wire's attachment height to the tower, the airplane's estimated altitude at the time of the wire strike was about 125 feet above ground level.
Medical and Pathological Information
The State of Oklahoma, Office of the Chief Medical Examiner, performed an autopsy. The cause of death was multiple blunt force injuries. The autopsy revealed an enlarged heart, severe atherosclerotic disease of one coronary artery with greater than 80% narrowing of the proximal right coronary artery, mild to moderate disease of the left anterior descending coronary artery, and a poorly defined area of myocardial fibrosis on the left ventricular free wall. Toxicology testing identified ibuprofen in urine; verapamil and norverapamil in blood and urine; and rosuvastatin in urine. Verapamil is used to treat high blood pressure; rosuvastatin reduces cholesterol. Neither medication is considered a hazard to flight safety.