N965DMSocata TBM 700 · 2009

On October 2, 2020, at 1144 eastern daylight time, a Socata TBM 700, N965DM, was destroyed when it was involved in an accident near Corfu, New York. The private pilot and passenger were fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight.

The airplane was serviced with 173 gallons of Jet A fuel on the morning of the accident, which filled the tanks. The first flight departed Buffalo Niagara International Airport (BUF), Buffalo, New York, at 0747 and landed at Manchester Airport (MHT), Manchester, New Hampshire, at 0914, where the passenger was boarded. No services were received before the airplane departed on the accident flight.

Radar data provided by the Federal Aviation Administration (FAA) depicted its departure at 1019, and a climb to flight level (FL) 280 where it remained in level flight. Air traffic control (ATC) voice communication data revealed the pilot checked in with the Boston Air Route Traffic Control Center following a frequency change issued by a previous controller, and about 25 minutes elapsed before the pilot established communication with Buffalo Approach Control when he was about 30 miles east of BUF.

On the initial contact, the pilot told the radar controller he had lost communication with center and was level at FL280. About 1141, the controller instructed him to descend to 8,000 ft and to expect the instrument landing system (ILS) runway 23 approach; radar data show the airplane began its descent about this time. A few seconds later, the controller asked the pilot if “everything was okay...” and the pilot responded, “yes sir, everything’s fine.” The controller then cleared the pilot to fly direct to BUF and to expect vectors for a left downwind t0 the runway 23 ILS. The pilot acknowledged this clearance.

About 2 minutes later, the controller asked the pilot where he was headed, and the pilot provided a “garbled” response. The controller then instructed the pilot to stop his descent and to maintain 10,000 ft, followed by an instruction to stop his descent and to maintain any altitude. The pilot did not respond, and several additional attempts to contact the pilot were unsuccessful.

Witnesses in the area surrounding the crash site reported that the engine sound was “very loud” before the sound of impact was heard.

The pilot reported having flown 60 hours during the 6 months before his last FAA medical examination. The pilot’s logbook reflected a flight on May 20, 2019, and completion of a SimCom recurrent course for the TBM850 on February 9, 2020. A summary of the logbook review revealed the pilot’s hours of flight experience during the 4 years prior to the accident.

Year

Total Flight Hours

TBM Flight Hours

2016

100.2

90.1

2017

53.9

53.9

2018

70.1

70.1

2019

25.1

25.1

According to FAA records, the pilot purchased the airplane in June 2016. It was powered by a Pratt & Whitney Canada PT6A-66D, 850-horsepower engine equipped with a Hartzell constant-speed propeller.

According to the airplane flight manual, the airplane was equipped with an altimetric valve that provided an automatic passenger mask actuation function at a cabin altitude between 13,000 ft and 14,000 ft when the oxygen switch was set to ON.

The 1154 recorded weather observation at BUF, located about 17 miles west of the accident location, included wind from 250° at 9 knots, visibility 10 miles, few clouds at 2,000 ft above ground level (agl) and 3,500 ft agl, broken cloud layers at 6,000 ft agl and 14,000 ft agl, temperature 13°C, dew point 8°C, and an altimeter setting of 29.97 inches of mercury.

According to high-resolution rapid refresh model sounding for the accident site around 1200, the wind at FL190 was from the west about 25 knots. Relative humidity about FL190 was 33% and the relative humidity was above 90% for the entire atmosphere above about 9,000 ft. The freezing level was identified as about 5,200 ft. Calculations made by the Rawinsonde Observation Program (RAOB) did not identify any potential for icing, clouds, or significant turbulence between about 9,000 and 27,000 ft.

According to FAA records, the pilot purchased the airplane in June 2016. It was powered by a Pratt & Whitney Canada PT6A-66D, 850-horsepower engine equipped with a Hartzell constant-speed propeller.

According to the airplane flight manual, the airplane was equipped with an altimetric valve that provided an automatic passenger mask actuation function at a cabin altitude between 13,000 ft and 14,000 ft when the oxygen switch was set to ON.

The airplane impacted a heavily wooded, swampy area. The airplane was fragmented and damaged by postcrash fire. Wreckage and components of the airplane were buried 15 ft below the surface. All of the major components were accounted for at the scene. An odor of Jet A aviation fuel was noted at the accident site by first responders.

The fuselage was fragmented by impact forces. The door locking pins on the main cabin door were extended and the door handle was in the closed position. A passenger emergency oxygen mask was located separated from the airframe, but the mask remained inside its housing. Control cable continuity could not be confirmed due to the fragmentation of the fuselage. All sections of the cables and push-pull tubes located exhibited tensile overload fractures. The autopilot aileron and trip servos were located, and all cables exhibited tensile overload failures. A majority of each primary and secondary flight control surfaces were in the fragmented wreckage.

Both the forward and aft sections of the center wing spar were bent symmetrically about 43° aft from their original positions. The left elevator trim tab was separated from the left elevator and located in four sections. The inboard section of the right elevator trim remained attached to the elevator. The elevator trim actuators were located and measured 16mm, consistent with a neutral position. The rudder was impact separated from the vertical stabilizer. The top section of the rudder and rudder trim tab were not located. The tailcone was impact separated and located in the wreckage.

Examination of the engine revealed that the accessory gearbox and inlet case were impact-separated, and they were not located. Multiple parts of the power turbine section and compressor section of the engine exhibited rotational scoring. Multiple blades were fractured, smeared, and bent the opposite direction of travel. The fracture surfaces that were not smeared exhibited features consistent with overload.

The propeller hub was impact-separated from the engine. All five blades were impact-separated from the hub. A portion of each of the five blades was found in the wreckage.

Performance Study

A performance study was conducted using airplane weight, radar, communications, and weather data. The results indicated the airplane was in cruise flight at 28,000 ft and about 190 knots calibrated airspeed (KCAS) until 1141:17, when over a 30-second span, the nose pitched down about 10° and the rate of descent increased to 4,500 ft/minute. The descent was initiated 15 seconds after the airplane was cleared to descend from its cruising altitude. The airplane maintained its assigned heading until 1143:31. At that time, the airplane descended through 19,300 ft and accelerated through its maximum operating speed of 271 KCAS.

The study showed that the airplane then entered a right banking turn that reached nearly 90°, with a pitch-down attitude of 47°. Both airspeed and rate of descent increased in the descending turn. Airspeed reached 350 KCAS and the rate of descent peaked at 28,400 ft/min at 1144:13, and then decreased to 6,800 ft/min at the end of the data. The computed normal load factor increased to about 3.8 G during the descent. The study noted the descent profile was consistent with a spiral dive.

Limitations

According to the manufacturer, the airplane autopilot engagement limitation for angle of bank was +/-45° and -15° for descending pitch angle. In addition, the autopilot operational envelope (commands limit) was +/- 25° for bank angle and -10° for descending pitch angle. Furthermore, the airplane was equipped with an emergency descent mode that, when engaged, would signal the autopilot to initiate a 90° left turn and descent up to 4,000 ft/min (depending on airplane loading, power lever positions, and weather conditions) until the airplane reached the target altitude of 15,000 ft msl.

According to the autopsy report from the Office of the Medical Examiner, Monroe County, New York, the cause of the pilot’s death was multiple blunt force injuries, and the manner of death was accident. The examination was limited by the extensive injuries.

Toxicology testing performed by the FAA Forensic Sciences Laboratory detected ethanol in the pilot’s muscle tissue at 0.022 grams per hectogram (gm/hg). No other tested for drugs were detected in his muscle tissue. Toxicology testing performed for the medical examiner’s office was negative for ethanol and tested for drugs in the pilot’s muscle tissue.

Ethanol is a social drug commonly consumed by drinking beer, wine, or liquor. It acts as a central nervous system depressant; it impairs judgment, psychomotor functioning, and vigilance. Ethanol is water soluble, and after absorption it quickly and uniformly distributes throughout the body’s tissues and fluids. The distribution pattern parallels water content and blood supply of the tissue. Ethanol can be produced after death by microbial activity; sometimes in conjunction with other alcohols, such as propanol. Extensive trauma increases the spread of bacteria and raises the risk of ethanol production after death.