HISTORY OF FLIGHTOn May 12, 2020, about 1126 eastern daylight time, a Beech F33A, N711JA, was destroyed when it was involved in an accident near Land O Lakes, Florida. The pilot was fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The airplane was based at Clearwater Air Park (CLW), Clearwater, Florida. Earlier during the day of the accident, the pilot flew the airplane uneventfully from CLW to Tampa North Aero Park (X39), Tampa, Florida, and was returning to CLW at the time of the accident. Runway 32 at X39 was 3,541 feet long, 50 feet wide, and consisted of asphalt. According to witnesses at X39, the pilot performed an engine run-up near the beginning of runway 32 and the engine sounded normal. The pilot then taxied onto the runway for departure, but, as soon as the engine reached full power, it began to sound abnormal, rough, and/or lean. The pilot then reduced engine power and taxied to runway 14, performed another engine run-up and the engine sounded normal. However, the engine again began to run rough when it reached full power for takeoff. The pilot reduced the engine power and taxied to the beginning of runway 32. He performed a third engine run-up and the engine sounded normal. As the engine reached full power, it began to run rough again, but the pilot continued the takeoff roll. The airplane travelled more than half the distance of the runway before it lifted off, “barely” cleared trees at the end of the runway, and made a left turn. One of the witnesses radioed the pilot and advised that he had a rough running engine, the pilot replied “ya, returning,” followed by “going down.” WRECKAGE AND IMPACT INFORMATIONExamination of the accident site by a Federal Aviation Administration inspector revealed that the airplane came to rest upright in the backyard of a vacant residence about 1/2 mile west of the departure end of runway 32. All major components of the airplane were accounted for and a postcrash fire consumed most of the cockpit, cabin, and right wing. The left wing had separated during the impact and was also located in the back yard of the residence, north of the main wreckage. The engine was subsequently examined at a recovery facility. When the propeller flange was rotated by hand, crankshaft, camshaft, and valve train continuity were confirmed to the rear accessory section of the engine. Thumb compression was attained on all cylinders and a borescope examination of the cylinders did not reveal any anomalies. The top spark plug electrodes did not exhibit any anomalies and the fuel nozzles were free of obstructions. Disassembly of the fuel manifold revealed corrosion and loose material associated with corrosion inside the manifold. The fuel lines leading to the fuel manifold had partially melted during the postcrash fire, preventing any water from entering the fuel manifold after the accident. The rear accessory section exhibited the most thermal damage. ADDITIONAL INFORMATIONA copy of video recorded from a doorbell camera at a residence near the accident site was forwarded to the National Transportation Safety Board Vehicle Recorders Laboratory, Washington, DC. A sound spectrum study of the video revealed that during the 10 seconds prior to impact, two identified areas were consistent with a drop, followed by a surge, in propeller rpm. MEDICAL AND PATHOLOGICAL INFORMATIONAn autopsy was performed on the pilot by the State of Florida, District Six Medical Examiner’s office, Largo, Florida. The cause of death was thermal injuries. Toxicology testing was performed on the pilot by the laboratory at FAA Forensic Sciences. The results identified trazodone at 317 ng/ml and gabapentin at 525 ng/ml. Review of personal medical records reflected long standing depression and the use of trazodone and gabapentin for many years. The FAA’s Guide for Aviation Medical Examiners indicated that the use of psychotropic and anticonvulsant drugs was disqualifying for aeromedical certification purposes. The pilot’s most recent medical examination was completed on March 1, 2019, and he was issued a second-class medical certificate. During that and previous examinations, the pilot reported only orthopedic issues and denied the regular use of any medication.