History of Flight
On August 20, 2021, at approximately 1440 eastern daylight time, a Socata TBM 700A, registration N700DT, was destroyed in an accident near Urbana, Ohio. The pilot sustained fatal injuries. The aircraft was operated as a personal flight under Title 14 Code of Federal Regulations Part 91.
According to air traffic control information, the airplane departed Erie-Ottawa Airport (PCW) in Port Clinton, Ohio, at 1412, en route to Cincinnati Municipal Airport (LUK). After departure, the airplane climbed to 20,000 ft msl before beginning a descent. At 1432, the pilot contacted the terminal radar approach control controller while southbound descending to 11,000 ft msl. At 1436, the controller cleared the pilot to descend to 10,000 ft msl and proceed direct to LUK. The pilot acknowledged the clearance. About 98 seconds later, while descending through 13,000 ft msl, the airplane entered a left turn. At 1438, the controller observed the turn and asked if everything was alright; there was no response. Radar contact was lost, and further communication attempts were unsuccessful.
A witness located about 2 miles south of the accident site reported seeing the airplane at high altitude in a nose-dive descent, not turning or spinning, with the engine at full throttle. No smoke, fire, or parts separation was observed. The witness lost sight as the aircraft descended behind trees.
The accident site was 1.3 miles northwest of the last radar contact. On-scene evidence showed the airplane impacted two powerlines, trees, and terrain in a shallow descent with a slightly left-wing low attitude.
Aircraft and Pilot Information
The pilot had purchased the airplane about 9 days before the accident. Previously, he had owned and flown Piper PA-46-310P/350P aircraft for about 20 years. After purchasing the TBM, the pilot completed ground school and 15.5 hours of dual instruction with a flight instructor. The instructor described the pilot as a good student in good health, comfortable with the aircraft systems, and advised him to fly solo for 10-15 hours to gain comfort. The accident flight was the pilot's third solo flight in the airplane; he planned to pick up a family member at LUK.
Maintenance on the aircraft included an A+ inspection and annual inspection on August 6, 2021, and a borescope inspection of the engine turbine section on August 19, 2021, with no defects noted. The pilot last refueled on August 14, 2021, in Cleveland, Ohio, and conducted two subsequent flights totaling about 1.5 hours. The amount of fuel remaining after those flights was unknown.
Meteorological Information
No significant meteorological information, precipitation, or forecast issues were reported in the area at the time of the accident. Reported weather included scattered cloud tops between 7,000 ft and 9,000 ft msl.
Wreckage and Impact Information
The initial ground scar was in a residential yard, containing separated left wing components. A debris path extended across a highway, through trees and a ditch, into potato and soybean fields. The highly fragmented wreckage was scattered over about 2,050 ft along a measured magnetic heading of 275°. An odor of Jet A fuel was noted by first responders.
The cockpit and fuselage were fragmented by impact forces. Flight control cable continuity could not be established due to fragmentation; all cable sections showed tensile overload fractures. The left wing separated at the root and fragmented; the right wing also separated near the root. The flap jackscrew was in the flaps UP position. Elevator trim was found in about the full nose-up position; rudder trim was neutral. The right main landing gear actuator was locked UP.
Examination of cockpit annunciator panel light bulbs found no filaments with hot stretch. The engine accessory gearbox and forward propeller shaft were separated; multiple parts showed rotational scoring. The propeller hub was separated from the engine shaft; all five blades were separated from the hub.
Additional Information (Performance Study)
The NTSB conducted an Aircraft Performance and Simulation Study using ATC data, Garmin GTN 750 GPS data, wreckage evidence, weather information, and performance data. The airplane was not equipped with a flight data recorder or cockpit voice recorder. The GTN 750 recorded parameters including altitude, position, airspeed, heading, pitch, roll, and load factors.
The airplane began descending from 20,000 ft msl at 1433 with a descent rate of about 1,600 ft/min, increasing to 235 KCAS by 1438:20 at 13,000 ft msl. At 1438:20.5, the airplane started rolling left at about 7°/second, exceeding autopilot roll authority limits. The roll angle reached about 110° left wing down before partially returning to 62° left wing down. Pitch angle decreased to 53° nose down and then increased to 45° nose down as the roll angle lessened. The GTN 750 data ended at about 4,200 ft msl, roughly 3,200 ft above terrain, with a descent rate of about 30,000 ft/min but decreasing. The airplane was about 1 nm from impact; simulations indicated about 11 seconds to cover the distance.
The study evaluated three scenarios: Controls, Imbalance, and Recovery. The Controls scenario used symmetrical loading and showed little yoke/wheel force required. The Imbalance and Recovery scenarios assumed a 420-pound fuel imbalance (left wing heavier), which matched the initial roll with zero wheel force applied, simulating autopilot disengagement. The Recovery scenario indicated that substantial wheel and column forces were required to maneuver the airplane from the end of recorded data to the impact point. The study noted that a turbulence encounter producing more than 1.6 Gs could have disengaged the autopilot. However, the behavior of the pilot and his activity on the flight controls during the initial roll and dive remained an unknown factor.
Medical and Pathological Information
An autopsy by the Montgomery County Coroner determined the pilot's cause of death as multiple blunt force injuries. The examination was limited by the extent of injury; the brain and heart were not available. Toxicology testing by the FAA identified ethanol at 0.018 gm/dl in cavity blood, 0.010 mg/hg in liver, and 0.020 mg/hg in lung. No other substances were detected. The report noted that ethanol may be produced postmortem by microbial activity, and extensive trauma increases the risk of such production.