Accident Sequence
On September 12, 2023, at about 1200 central daylight time, a Thrush Aircraft LLC S2R-T660 airplane, registration N710TY, was substantially damaged during an accident near Ardoch, North Dakota. The pilot was fatally injured. The flight was conducted under Title 14 Code of Federal Regulations Part 137 as an aerial-application operation.
The purpose of the flight was to spray a sunflower field. The airplane operated from a private airstrip near Osla, Minnesota. According to data recovered from the engine monitor, at 1152 the engine was set to takeoff power. Based on flight track data from the spray system, about 7 minutes after takeoff, the airplane approached the intended field from the south and flew around its perimeter.
The flight track data indicated that the airplane initially flew north along the east edge of the field before completing a left 180° turn to reverse course and continue south along the west edge. The airplane then flew south while remaining west of power lines running north/south along the west edge. As the airplane flew south, the left wing impacted a guy wire attached to a power line structure.
The outboard 7 ft of the left wing and the left aileron separated during the impact and were subsequently found in an adjacent soybean field. The separated portion showed evidence of a wire strike through the wing leading edge and along the forward spar. The airplane continued south about 0.3 mile before it crashed in a cornfield on an east-southeast trajectory.
At 1200:28, the final recorded flight track point was about 172 ft west-northwest of the initial ground impact in the cornfield.
Aircraft and Wreckage Information
The airplane had undergone recent inspections. On August 3, 2023, a 100-hour engine inspection was completed at 98.6 hours total time since new. On August 28, 2023, a 300-hour airframe and 100-hour engine inspection was completed at 296.8 hours total time since new. According to the digital engine monitoring system, at the time of the accident, the airplane hour meter indicated 415.88 hours and the engine hour meter indicated 324.17 hours. The engine monitor had recorded 124 engine start cycles and 526 takeoffs.
The airplane impacted the cornfield in a left-wing-down and nose-down attitude. The main wreckage was located about 155 ft on a 101° bearing from the initial ground impact. An impact crater containing one propeller blade was located about 50 ft east-southeast of the initial impact point. The engine, propeller, and main landing gear were separated. The airplane came to rest upright in a nose-down attitude on a northeast heading. The fuselage and cockpit rested on the separated wing, which was found inverted. Except for the separated outboard 7 ft of the left wing and left aileron, all structural components and flight control surfaces were at the accident site.
Examination of the wreckage revealed no evidence of a preimpact malfunction that would have prevented normal operation. Flight control continuity could not be confirmed due to impact damage, but all control cable and push/pull tube separations were consistent with impact-related damage or cuts made during recovery. The flaps appeared fully retracted. The right wing fuel tank contained fuel, which drained through a breach during recovery.
The engine showed evidence of high-velocity impact and separation from the airframe. It came to rest about 60 ft beyond the main wreckage. Examination of the engine did not reveal any preimpact mechanical malfunction or failure. The propeller assembly separated from the propeller shaft flange. Two blades impact-separated from the hub and were found in the debris field. Two of three blades still attached exhibited forward-bending in the thrust direction, twisted towards high pitch, and slipped in retention clamps. Three of five blades exhibited aft-bending and twisting towards low pitch. All blades showed chordwise rotational scoring, leading edge gouging, and bending opposite the direction of rotation.
The power line structure had three guy wires; the third, middle guy wire separated from the structure during the impact but remained attached to the ground anchor. The guy wire was 3/8-inch outside diameter, normally attached to the pole crossarm near the top of a 73 ft tall pole. According to the power company, the guy wire was about 95 ft long and attached at about 65 ft above ground level, anchored about 62 ft west of the pole. Examination revealed damage about 82 ft from the ground anchor.
Medical and Pathological Information
The University of North Dakota Forensic Pathology Department performed the pilot's autopsy at the request of the Grand Forks County Coroner's Office. According to the autopsy report, the cause of death was multiple traumatic injuries, and the manner of death was accident. Toxicological testing by the FAA Forensic Sciences Laboratory did not detect any carboxyhemoglobin, ethanol, glucose, or tested-for drugs.
Engine Data at Impact
A review of recorded engine monitor data showed that in the moments before ground impact, the gas generator was operating at 96.4%, the propeller at 1,520 rpm, engine torque at 39.5 psi, inter-turbine temperature at 702°C, fuel flow at 88.2 gallons per hour, fuel pressure at 21 psi, and oil pressure at 119 psi.