HISTORY OF FLIGHTOn June 25, 2023, about 1620 eastern daylight time, a Mooney M20R, N13LV, was destroyed when it was involved in an accident near Southport, North Carolina. The pilot was fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. According to a mechanic at Cape Fear Regional Jetport (SUT), Oak Island, North Carolina, the airplane had been in for maintenance since October 2022. The private pilot/owner had requested that the mechanic troubleshoot interior lighting, service the brakes, attach a standby vacuum hose, and repair an exhaust leak. The mechanic could not complete the work as he could not start and run up the engine due to dead batteries. When he inspected the batteries, he realized that they were unairworthy. Specifically, the airplane was designed with a 24-volt electrical system that utilized two 24-volt batteries; however, the mechanic found four 12-volt batteries installed. When the mechanic contacted the pilot about the discrepancy, the pilot instructed him to reinstall the four 12-volt batteries. The mechanic refused, as it would have been an unapproved and unairworthy installation. The pilot then stated that he wanted his airplane back. The mechanic told him that the airplane was unairworthy, as he had not completed repairs on it; he also noted that it was unairworthy on the invoice. On the day of the accident, witnesses at the airport observed excessive white exhaust smoke and oil leaking from the airplane onto the ground as it taxied from the mechanic’s hangar to runway 23 for takeoff. Shortly after takeoff, the pilot reported an engine failure on the common traffic advisory frequency and that he was returning to runway 23. Review of FAA ADS-B data revealed that the airplane departed runway 23 about 1617 and flew a left circuit back to runway 23; however, it impacted a residential area about 1/2-mile before the runway threshold. PERSONNEL INFORMATIONThe pilot’s logbook was not recovered. On his most recent application for an FAA second-class medical certificate, dated June 9, 2017, he reported a total flight experience of 3,945 hours. AIRCRAFT INFORMATIONThe aircraft logbooks were not recovered. According to the mechanic at SUT, the pilot had mentioned that the airplane’s most recent annual inspection was completed in Pennsylvania sometime during August 2022. AIRPORT INFORMATIONThe aircraft logbooks were not recovered. According to the mechanic at SUT, the pilot had mentioned that the airplane’s most recent annual inspection was completed in Pennsylvania sometime during August 2022. WRECKAGE AND IMPACT INFORMATIONThe wreckage came to rest in a residential yard, near the left rear side of the home, and a postimpact fire ensued; however, it did not ignite the home. The wreckage was laying on its right side, on a heading of about 090°. A debris path about 125 ft long was observed, beginning with the right aileron suspended in a tree that was about 40 ft tall, on a northwest course to the main wreckage. The left wing remained partially attached to the fuselage. The aileron and flap remained attached to the left wing. The flap was observed in an extended position; however, the flap control in the cockpit could not be identified. The right wing had separated and was resting underneath the left wing. The right aileron and flap had separated from the right wing. The flap was recovered near the right wing and the aileron was recovered from the tree. The landing gear was observed in an extended position. The empennage remained intact and oil streaks were noted on the underside. Flight control continuity was confirmed from the cockpit via push-pull tubes to all flight control surfaces except for the separated right wing, where aileron continuity was confirmed to the wing root. The cockpit and cabin were consumed by fire. The engine came to rest inverted, and the propeller remained attached to the engine. An oil sump accessory port plug was observed loose, with oily blue stained baffling material resting below it. Additionally, the No. 4 connecting rod had protruded through the top of the engine case. A check of the oil dipstick revealed no measurable oil in the engine. MEDICAL AND PATHOLOGICAL INFORMATIONAn autopsy was performed on the pilot by the North Carolina Office of The Chief Medical Examiner, Greenville, North Carolina. The cause of death was reported as “multiple thermal injures.” Toxicological testing was performed on specimens from the pilot by the FAA Office of Forensic Sciences, Oklahoma City, Oklahoma. The testing revealed positive results for carboxyhemoglobin, consistent with smoke inhalation. The testing results were also positive for the blood pressure medication carvedilol, the clot-prevention medication clopidogrel, and the diuretic furosemide, none of which are typically impairing.