History of Flight
On January 16, 2023, about 1242 central standard time, a Piper PA-32-301T, N8266D, was destroyed when it impacted terrain near Kingfisher, Oklahoma. The pilot and a certificated flight instructor sustained fatal injuries. The flight was conducted under Title 14 Code of Federal Regulations Part 91 as an instructional flight.
Witnesses observed the airplane trailing black smoke before it rolled over and descended into the ground. A witness-provided cell phone video confirmed the black smoke and an explosion after impact.
The accident flight was the first flight after the airplane underwent maintenance, including installation of a new autopilot system and an annual inspection. The owning flying club required members to fly with a club instructor to become acquainted with the new autopilot; this flight was such a checkout.
ADS-B data indicated the airplane departed Wiley Post Airport (PWA) in Oklahoma City about 1214. After takeoff, it traveled west about 17 nautical miles, then north another 14 nautical miles before beginning maneuvering. The airplane was at about 5,700 ft mean sea level (msl), remaining between 5,500 and 6,000 ft until about 1241, when it began descending. The final recorded position was about 4,000 ft msl, heading southeast. The accident site was about 1 nautical mile east of that position.
Wreckage and Impact Information
The airplane impacted a firm, level field with sparse vegetation. The initial impact crater contained the propeller, whose rotation axis was near vertical, consistent with a near-vertical descent attitude. All components were found in the immediate vicinity.
The main fuselage, wings, and tail surfaces came to rest about 100 ft north of the initial impact point. The wings were impact-damaged but continuous except for the center spar section, which was melted and consumed by fire. Ailerons and flaps remained attached. Leading edges were crushed aft, and all four fuel tanks were ruptured. The fuselage forward of the tail surfaces was almost entirely consumed by fire. The aft fuselage from the vertical stabilizer leading edge rearward was intact with tail surfaces attached. Control continuity was confirmed from all surfaces to the cockpit, with breaks consistent with impact damage.
The horizontal tail surfaces exhibited oil streaking from the leading edge toward the trailing edge in a longitudinal direction, consistent with an in-flight oil leak.
Examination of the airframe revealed no identifiable preimpact deficiencies; however, extensive impact and fire damage precluded comprehensive examination.
Engine examination confirmed crankshaft rotation, though with difficulty. Accessory gear continuity was confirmed, and valve action was noted on all cylinders. The fuel injection throttle body and induction plenum were separated from the cylinder intake tubes. The single-drive dual magneto was separated from the accessory case and found in the debris field, with its case fractured exposing internal components. The oil suction screen was removed and debris was found, retained for further examination. Less than 1/2 quart of oil was drained from the engine at the scene. The exhaust system had several separations; the turbocharger was displaced and had a hole in the induction side housing. The tailpipe had separated from the turbocharger but the V-band clamp remained. Subsequent removal of the oil sump revealed an undamaged rubber magneto drive cushion within the sump. There were no breaches in core engine components that would explain loss of engine oil. Apart from the debris on the oil suction screen, no preimpact defects were found in the core engine or accessories.
The extent of impact and fire damage precluded determination of the remainder of the airplane’s preimpact oil system integrity.
Medical and Pathological Information
The Office of the Chief Medical Examiner (OCME), Central Division, Oklahoma City, Oklahoma, performed the flight instructor’s autopsy. The cause of death was blunt force and thermal injuries, and the manner of death was accident.
The FAA Forensic Sciences Laboratory performed toxicological testing of postmortem muscle and lung tissue from the flight instructor. Delta-9-tetrahydrocannabinol (delta-9-THC) and its metabolites were detected in lung and muscle tissue. Quetiapine and its metabolite norquetiapine were also detected. Bupropion and its metabolite hydroxybupropion were detected. Venlafaxine and its metabolite O-desmethylvenlafaxine (desvenlafaxine) were detected. All detected substances were drugs or metabolites of drugs that the flight instructor had a documented history of using per reviewed medical records.
Delta-9-THC is the primary psychoactive chemical in cannabis. Marijuana is a federal Schedule I controlled substance, and the FAA considers its use by pilots unacceptable regardless of state laws. Quetiapine is a prescription antipsychotic medication. Bupropion is a prescription medication that acts on the central nervous system and can be used to treat depression and smoking cessation. Venlafaxine is an antidepressant medication.
The OCME performed the pilot’s autopsy; cause of death was blunt force and thermal injuries, and manner of death was accident. OCME screening of aortic blood for selected drugs of abuse did not detect any screened substances. The FAA laboratory tested postmortem muscle and lung tissue from the pilot; most of the same substances as in the flight instructor were detected at lower levels, but these results were considered unreliable for the medical investigation. No other substances were detected.
Tests and Research
A J.P. Instruments model EDM-830 engine monitor was recovered from the accident site. The data included a time index that did not coincide with ADS-B data, but the recorded flight track matched ADS-B data. The engine monitor data indicated normal engine operational parameters for most of the flight. About 2 minutes before the end of the data, engine oil pressure began to drop, reaching 0 psi about 12 seconds later. During that time, the exhaust gas temperature of cylinder No. 1 increased from about 900°F to 1450°F. About 24 seconds before the end of the data, all cylinder head temperatures, turbocharger inlet temperature, and oil temperature went offline; at the same time, the outside air temperature began increasing from about 10°C to over 800°C by the end of the data.
Examination of the debris from the oil suction screen using Fourier Transform Infrared (FTIR) spectrometry showed a strong match to the known material from the magneto drive cushion found within the engine oil sump.