History of Flight
On November 4, 2019, at 1532 eastern standard time, a Cessna 150M, registration N714LK, was destroyed when it impacted a tree in a cemetery near New Bedford, Massachusetts. The pilot, the sole occupant, was fatally injured. The flight was operated as a personal flight under Title 14 Code of Federal Regulations Part 91.
According to an employee of the fixed based operator at New Bedford Regional Airport (EWB), the pilot was cheerful and performed a preflight inspection for 10–15 minutes before departing around 1450. ADS-B data showed the airplane climbed to about 2,500 ft msl, tracked southwest for 20 minutes, then descended, turned northeast, flew along the shoreline, and proceeded north toward EWB. It descended to about 250 ft above ground over a golf course less than 3 nm from EWB, then executed a climbing right turn at increasing pitch attitudes to about 4,000 ft msl, followed by a rapid descent in a left circular pattern.
A witness in a nearby parking lot heard a sound "like a motor revving up high," saw the airplane "swoop down like it was going to land," climb very high, then "pivot on its left wing" before "coming straight down." The witness believed the airplane was "doing tricks."
Personnel Information
Interviews with friends and acquaintances indicated that performing aerobatics was highly unusual and uncharacteristic for the pilot, who was considered a very conservative pilot. A friend who flew regularly with the pilot noted the pilot often flew toward Newport, Rhode Island, then along the shoreline back toward West Island, Massachusetts, and typically contacted the EWB tower when inbound. The president of the EWB fixed based operator stated that staff monitored the tower frequency but did not hear any radio transmissions from the pilot, adding that the pilot "would never enter the airspace without calling."
Aircraft Information
The airplane was a Cessna 150M. According to the Pilot Operating Handbook, cabin heat is regulated by push-pull CABIN HT and CABIN AIR knobs. The left engine muffler has a shroud that forms a heating chamber for cabin heater air, which is routed to the cabin when the CABIN HT knob is pulled out.
A logbook entry indicated the muffler was last replaced on June 1, 2004, at tachometer time 4,321.5 hours, 742.9 hours before the accident flight, but the entry did not specify which muffler was replaced. The mechanic who performed the most recent annual inspection stated he opened each muffler shroud to inspect for stains, soot, or cracks and found no anomalies. The airplane was not equipped with any carbon monoxide (CO) detector. The Model 150 Series (1977) Service Manual recommends a general exhaust system inspection every 50 hours and a more detailed inspection every 100 hours. The airplane was generally inspected annually, with flight hour intervals ranging from 39 to 55 hours in the preceding 10 years.
Wreckage and Impact Information
The airplane impacted a tree in a near vertical nose-down attitude about 3.5 nm and 164° magnetic from EWB. The debris field extended about 240 ft from the tree on a heading of about 220°. The left wing with strut was located about 10 ft from the tree, followed by the empennage, cabin, and engine at 30 ft, the right wing at 40 ft, the carburetor at 87 ft, a ruptured fuel tank at 122 ft, and the main wheels and directional gyro at 240 ft. All major components were present.
The fuselage was significantly fragmented. Both wings were impact fractured and bent with leading edge damage consistent with tree impact. The empennage was impact fractured and bent. The instrument panel was largely fragmented. Engine controls were in the full forward position, and the cabin heat control was in the full aft (ON) position.
Engine examination revealed no pre-impact anomalies that would have prevented normal power production. The propeller remained attached, with both blades exhibiting aft bending, twisting, leading-edge gouging, and chordwise rotational scoring. Control continuity was established through overload fractures to the control surfaces.
The left muffler outer casing was impact crushed, exposing the end plate with an erosion hole and several smaller pin holes. The cabin heat shroud removed from the muffler showed additional evidence of internal deterioration. The muffler metal was corroded and thin, with pin holes on the sides. The right muffler was crushed and compacted, with its shroud (providing heated air to the carburetor heat control) remaining intact.
Additional Information
The FAA has issued advisory circular AC 20-32B (CO contamination), report DOT/FAA/AR-09/49, and Special Airworthiness Information Bulletins (SAIBs) CE-10-19 R1 and CE-10-33R1, recommending CO detectors and exhaust system inspections. Compliance with SAIBs and manufacturer service letters is not mandatory.
In 2004, the NTSB issued Safety Recommendation A-04-028 to require CO detectors in certain airplanes. The FAA concluded that proper inspection and maintenance of mufflers and exhaust systems are the primary method to prevent CO contamination, with CO detectors as a secondary method. The FAA stated that a lack of a CO detector alone is not unsafe. The recommendation was classified as "Closed – Unacceptable Action."
Medical and Pathological Information
The pilot's last aviation medical examination was on November 1, 2018, at which he reported prostate cancer, used no medications, and was issued a third-class medical certificate requiring corrective lenses.
An autopsy by the Commonwealth of Massachusetts Office of the Chief Medical Examiner determined the cause of death as multiple blunt force injuries. The autopsy identified coronary artery disease, including up to 80% stenosis of the left anterior descending coronary artery. Due to the severity of injuries, no brain information was available. No other significant natural disease was identified.
Toxicological testing detected the non-impairing prostate medication tamsulosin in the pilot's liver and muscle. One laboratory reported carboxyhemoglobin as "none detected at 12%" in pooled/cavity blood, but the other laboratory could not test carboxyhemoglobin because the available blood specimen was unsuitable.
Carboxyhemoglobin forms when carbon monoxide binds to hemoglobin, impairing oxygen delivery. Nonsmokers normally have levels below 1–3%; heavy smokers may have up to 10–15%. Symptoms of low-level CO exposure are nonspecific and may include headache, nausea, and tiredness, progressing to impairment or incapacitation at higher levels.