N539MAPiper Aircraft PA46R-350T · 2010

On December 31, 2023, at 1213 eastern standard time, a Piper PA-46R-350T, N539MA, was substantially damaged when it was involved in an accident near Mooresville, North Carolina. The pilot was fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight.

A family member reported that the pilot intended to take the airplane for a short local flight then refuel it for a family trip planned for the next day. According to ADS-B data for the accident flight, the airplane departed from runway 32 at Lake Norman Airpark (14A), Mooresville, North Carolina, about 1152 and climbed to an altitude of about 3,000 ft mean sea level (msl) on a northwest ground track, following the Catawba River for about 30 nm. The data showed that, at 1202, the airplane turned left then flew a direct course back toward 14A. The airplane’s ground speed was about 200 kts for the entire flight until about 1210, when it decreased, and the airplane began a descent. The airplane’s last ADS-B position was recorded at 1213. It showed that the airplane was at an altitude of 850 ft msl, which was about 60 ft agl. The accident site was about 488 ft southeast of the last ADS-B position, which was about 3/4 nm from the threshold of runway 14.

A witness located near the accident site reported hearing no engine noise from the airplane before the impact.

A security camera located at a private residence captured both video and audio of the accident airplane. The airplane was visible for 9 seconds as it traveled from right to left across the camera’s field of view, then the sound of impact occurred about 3 seconds later. When the airplane entered the camera’s field of view, it showed minor roll oscillations, its propeller was turning, then it started to bank to the right and lose altitude before it exited the field of view. A sound spectrum study performed on the captured audio calculated that the propeller rotation was about 1,100 rpm, which was consistent with the propeller windmilling.

Review of the airplane’s maintenance logbooks revealed that the engine was overhauled by the manufacturer on July 14, 2023. A maintenance record dated August 15, 2023, indicated that, during the engine installation, both turbochargers were removed and temporarily replaced with serviceable units so that the actions specified in Lycoming Special Advisory SA-203 and Hartzell Engine Technologies Service Bulletin SB-203 could be completed on the removed turbochargers. The last annual inspection was performed on August 15, 2023, at an airframe total time of 1,208.6 (48.2 hours before the accident). On September 18, 2023, at an airfame total time of 1,211.3 hours (45.5 hours before the accident), the left and right turbochargers were reinstalled (after the special advisory and service bulletin actions were completed).

Review of the airplane’s maintenance logbooks revealed that the engine was overhauled by the manufacturer on July 14, 2023. A maintenance record dated August 15, 2023, indicated that, during the engine installation, both turbochargers were removed and temporarily replaced with serviceable units so that the actions specified in Lycoming Special Advisory SA-203 and Hartzell Engine Technologies Service Bulletin SB-203 could be completed on the removed turbochargers. The last annual inspection was performed on August 15, 2023, at an airframe total time of 1,208.6 (48.2 hours before the accident). On September 18, 2023, at an airfame total time of 1,211.3 hours (45.5 hours before the accident), the left and right turbochargers were reinstalled (after the special advisory and service bulletin actions were completed).

Examination of the accident site and wreckage revealed that the airplane came to rest upright about 58 ft southeast of a severed treetop that was broken about 40 ft agl. A ground scar about 18 ft long and oriented to 159° true led up to the airplane. Several trees exhibited impact damage, and fallen branches were along the debris path. There was no evidence of fire, and all major components of the airplane were recovered from the accident site.

The fuselage, right wing, and most of the empennage remained intact. The left wing was impact fractured and resting inverted on top of the right wing. The left horizontal stabilizer was located in front of the cockpit, and the left elevator was separated and found in a tree. The right wing remained attached by the aft wing attachment. Both main wing spars were fractured at the respective wing root, and both wings exhibited damage consistent with tree impact. The flaps and landing gear were retracted. Both the left and right wing fuel tanks contained fluid consistent in odor and color with 100LL aviation fuel.

The fuel vents were examined and both the main fuel vent systems contained reddish colored dirt, which was similar to the dirt surrounding the airplane at the accident site. The left main fuel vent system was completely obstructed, and the right main fuel vent system was only partially obstructed. The left fuel tank vented cap was tested and found to operate normally. The fuel selector handle was positioned to the left tank. The emergency fuel pump switch was in the “ON” position. The engine remained attached to the fuselage at the engine mount.

The three-blade, constant-speed propeller remained attached to the engine and was impact damaged. Two of the three composite propeller blades were detached at the blade roots. The blade that remained attached to the propeller hub displayed chordwise tears. One of the detached blades was fractured. None of the blades displayed chordwise abrasion, twisting, or bending, and no leading-edge damage was observed.

The throttle, propeller, and mixture levers were in their full forward positions. Flight control cable continuity was confirmed from the cockpit area to each of the respective control surfaces through separations consistent with accident forces.

Examination of the engine revealed continuity of the crankshaft to the rear accessory gears and to the valvetrain. Thumb compression and suction were observed from all cylinders when the crankshaft was rotated. The left and right magnetos were removed, and sparks were observed on all towers when each magneto’s input driveshaft was rotated. Examination of the engine’s cylinders with a lighted borescope revealed no anomaly. The top spark plugs were removed and showed signs of heavy carbon deposits. The emergency fuel boost pump was removed and operated when electrical power was applied. Air was applied and flowed throughout the fuel lines. When the fuel flow divider was removed and disassembled, a small amount of fluid consistent with 100LL aviation fuel was found in the flow divider. No contamination was noted, and the diaphragm was in good condition.

Examination of the induction system found that the induction hose that connected to the left side intercooler was missing the clamp, and the hose coupling was displaced from the intercooler. The clamp was not observed during the examination.

The engine was shipped to the manufacturer for further examination. All six cylinders were removed from the crankcase assembly; the cylinder walls displayed minor surface corrosion consistent with postaccident exposure to the elements. The pistons displayed normal amounts of combustion deposits and there were no signs of detonation, preignition, or valve strikes. All the compression and oil control rings were intact and displayed normal operating signatures. The tappets, push rods, and rocker arms all displayed normal operating and lubrication signatures. All the exhaust valves moved normally within the valve guides and displayed normal operating, combustion, and lubrication signatures. The intake valves moved freely in their valve guides, and no sign of excessive carbon buildup between the valve stems and the guides was observed. The intake valve heads for the Nos. 2, 3, 4, and 6 cylinders were dark and black in color, consistent with carbon fouling. The intake valve heads for the Nos. 1 and 4 cylinders displayed normal operating and combustion signatures.

The engine-driven fuel pump was removed and did not contain any fuel. Its input drive rotated freely by hand and flowed fuel when tested. When tested on a production test bench, the fuel pump operated normally at all tested conditions except for the 650 rpm setting, which resulted in a low flow rate of 2 lbs per hour, which is below the specified 9 lbs per hour for a new or overhauled fuel pump. The flow rate at 1,100 rpm was 90 lbs per hour. The fuel pump was disassembled, and no anomaly or mechanical failure was found that would have precluded normal operation.

The fuel servo was intact and undamaged. Upon removal, fluid consistent with 100LL aviation fuel was observed coming from the inlet to the servo fitting and from the fuel pressure sensor fitting. The throttle plate moved appropriately when the throttle arm was actuated. The fuel injection servo was further examined and tested at the manufacturer’s facility. The fuel injection servo’s observed flow was slightly rich at two of the test points; the highest discrepancy was 1 lbs per hour over the maximum. The fuel injection servo was disassembled, and all the internal components displayed normal operating signatures. No anomaly or mechanical failure was found that would have precluded normal operation.

The magnetos and spark plugs were examined and tested at the manufacturer’s facility. The examination revealed that all of the spark plugs showed signs of heavy carbon fouling, consistent with a rich mixture. All of the spark plugs were capable of producing a spark utilizing the testing equipment. Both magnetos were placed on a test bench and were able to pass the manufacturer’s test against new part specifications.

Both turbochargers, the wastegate actuator, and the overboost valve were examined at the manufacturer’s facility. Both of the turbochargers were heavily impact damaged at the compressor sections of the turbochargers. The compressors and turbine sections displayed impact marks on their respective housings that were consistent with static or slow rotation rub. The wastegate actuator and the overboost valve displayed normal operating signatures. No anomaly was found that would have precluded normal operation.

The pilot’s last aviation medical examination was November 5, 2022. At that time, he reported a history of high blood pressure, which was noted to be qualified under Conditions Aviation Medical Examiners Can Issue (CACI) criteria. The pilot reported using losartan, which is a prescription medication commonly used to treat high blood pressure. The pilot was issued a third-class medical certificate limited by a requirement to have available glasses for near vision.

The pilot’s autopsy was performed at Wake Forest Baptist Medical Center in the North Carolina Medical Examiner System. According to the pilot’s autopsy report, his cause of death was multiple blunt force injuries, and his manner of death was accident. The pilot’s autopsy identified mild-to-moderate multivessel coronary artery disease, moderate calcific stenosis of the aortic valve, and moderate ulcerated plaque in the abdominal aorta. The remainder of the autopsy, including visual examination of the heart, did not identify other significant disease.

FAA Forensic Sciences Laboratory postmortem toxicological testing detected diphenhydramine in aortic blood at 42 ng/mL and in urine at 576 ng/mL. Diphenhydramine is a sedating antihistamine medication widely available over the counter in multiple sleep aids and cold and allergy products. Diphenhydramine can cause cognitive and psychomotor slowing and drowsiness and often carries a warning about driving and operating machinery. The FAA states that pilots should not fly within 60 hours of using diphenhydramine, to allow time for it to be cleared from circulation.