History of Flight
On February 21, 2018, at 1615 central standard time, a Piper PA-28-140, N3568K, was destroyed when it impacted terrain while landing at Tri-County Airport (1J0), Bonifay, Florida. The commercial pilot was fatally injured. The airplane was privately owned and the pilot was operating under Part 91. Day visual meteorological conditions prevailed, and no flight plan was filed for the local flight, which originated from 1J0 about 1600.
The owner stated that he had flown the airplane before the accident flight. He departed runway 19, climbed to 1,800 ft mean sea level, and maneuvered near the airport for a few minutes. He reentered the traffic pattern and completed a touch-and-go landing. The engine operated normally during this portion of the flight; however, during the initial climb after the touch-and-go, the airplane "seemed like it didn't want to fly." The owner verified that the throttle, mixture, and carburetor heat were full forward. The engine was not popping or shaking and was not running rough, but it would not produce full power. The owner declared an emergency, made a 180° turn, and landed uneventfully. He performed an engine run-up with no abnormalities and taxied to his hangar, reporting the anomaly to his mechanic.
The mechanic immediately boarded the airplane, started the engine, and performed a run-up; the engine sounded normal. He asked the owner to join him for a test flight multiple times, but the owner declined. The mechanic departed runway 19, made a left turn, and entered the downwind leg at normal traffic pattern altitude. The owner observed the airplane descend on the downwind leg and turn onto a left base leg before disappearing behind trees. Shortly after, he saw a plume of smoke and rushed to the accident site, where the airplane was engulfed in flames.
A witness outside his home on the approach to runway 19 stated that the airplane "didn't sound right" as it flew overhead, with the engine making "little explosions" or "backfires." He observed the main landing gear brush a tall tree, then continue south out of view. Shortly after, he heard an impact and saw a fireball.
Personnel Information
The mechanic held an airframe and powerplant mechanic certificate, as well as a commercial pilot certificate with ratings for airplane single- and multi-engine land and instrument airplane. His logbook showed 816.2 total flight hours (30.3 in the accident airplane) as of February 14, 2017, when he completed his last flight review. No flights were logged after this date. His most recent FAA second-class medical certificate was issued on June 26, 2016.
Aircraft Information
The low-wing, four-seat airplane was equipped with a Lycoming O-320-E2A engine and a two-bladed Sensenich propeller. Maintenance records indicated the last annual inspection was conducted on June 5, 2017, at a tachometer time of 3,951.77 hours, with 715.3 hours since engine overhaul. The airframe total time was 5,207.57 hours. The owner reported that the airplane had flown only a few hours since the annual inspection, and he had not experienced any engine problems before the accident day. The owner purchased 20 gallons of 100LL aviation gasoline before his flight, with total fuel before departure of 50 gallons (48 usable).
Meteorological Information
1J0 was not equipped with weather reporting equipment. A witness reported wind from the south at 10-20 knots, visibility 10 statute miles, and scattered to overcast sky condition at the accident time. At 1556, reported weather at Cairns Army Airfield (OZR), about 27 nautical miles north, included wind from 140° at 8 knots, visibility 10 miles, scattered clouds at 5,000 ft, broken clouds at 6,000 ft, temperature 28°C, dew point 17°C, and an altimeter setting of 30.28 inches of mercury.
Airport Information
The airport is Tri-County Airport (1J0), Bonifay, Florida.
Wreckage and Impact Information
Examination revealed damage consistent with the airplane striking a 60-ft-tall tree about 1/4 mile from the runway before impacting the ground and colliding with the airport's chain-link perimeter fence. The airplane came to rest upright just north of the runway threshold on a heading of 35°. A postimpact fire consumed most of the wreckage; all major components were accounted for. Flight control continuity was established to the cockpit. The flaps were fully retracted, and the fuel selector was set to the right tank.
The engine remained secured to the airframe; the cowling had burned away. The engine-driven fuel pump was attached but destroyed by fire. Both magnetos remained attached but were destroyed and could not be tested. Fuel lines from wings to carburetor were destroyed by fire. The carburetor was thermally damaged and removed; the bowl was empty, and the inlet fuel screen was absent of debris.
The engine, with propeller attached, was removed and examined. Top spark plugs showed low service life and color consistent with normal combustion. The No. 2 cylinder bottom spark plug could not be removed due to exhaust header pipe deformation. The No. 4 cylinder bottom spark plug had dislodged and was not recovered. The engine was manually rotated; compression and valve train continuity was established for all cylinders except No. 4. The No. 4 cylinder was removed; the exhaust valve was found seized in the valve guide in the open position, with some deformation on the valve face. The valve and piston face showed substantial carbon deposits. The No. 4 cylinder barrel bore appeared worn, and piston rings were heat-compressed in the ring lands.
Additional Information
Valve sticking in Lycoming reciprocating aircraft engines is addressed in Lycoming Mandatory Service Bulletin 388C and Service Instruction 1485A. Service Bulletin 388C, not mandatory for Part 91 operations, calls for inspection at 400-hour intervals or earlier if valve sticking is suspected. If the valve and guide do not pass inspection, corrective action per Service Instruction 1485A is required. After replacement with Hi-Chrome guides, inspection is called for every 1,000 hours or when valve sticking is suspected. Review of the airplane maintenance logs revealed that the valve guides and stems had not been inspected per Service Bulletin 388C at the recommended 400-hour interval.
Medical and Pathological Information
The District 14 Medical Examiner performed an autopsy; the cause of death was determined to be "airplane crash." The FAA's Bioaeronautical Sciences Research Laboratory performed toxicology testing; results were negative for carbon monoxide, ethanol, and all tested-for drugs. Friends reported the pilot was diabetic with blood glucose control issues. Additional testing revealed glucose at 18 mg/dl in vitreous, 22 mg/dl in urine, and hemoglobin A1C of 8.2%. Postmortem, normal vitreous glucose is below 200 mg/dl; below 150 mg/dl is normal in urine. Hemoglobin A1C is a measure of average blood glucose over several weeks; non-diabetic levels are below 5.4%, pre-diabetes 5.5%-6.4%, diabetes above 6.5%, good control below 7.0%, and poor control above 9%.