HISTORY OF FLIGHTOn June 15, 2018, about 1700 Pacific daylight time, a Beech A35 airplane, N580B, was destroyed when it was involved in an accident in Hesperia, California. The pilot and passenger were fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. A witness located on the road at the south end of the airport reported that the takeoff appeared normal. When he saw the airplane again it was traveling in the opposite direction from the departure and at an altitude about powerline level. He then observed a fireball about 10 ft above the airplane before it impacted the ground in a nose low attitude with the wings vertical to the ground. The airplane then cartwheeled before it came to rest. Another witness located in a parking lot south and west of the departure end of the runway reported that the airplane's climb appeared normal, however, something came off the airplane near the end of the runway. The airplane climbed to about 800 ft before the nose dropped and it made a "radical left turn." After the turn, the wings appeared vertical and the airplane lost about 400 ft. The airplane leveled out and appeared to be going back toward the airport, however, the nose remained low. The airplane then turned right and appeared to align with a road before it went out of his sight. An off-airport video captured the airplane's initial climb. The airplane climbed to an undetermined altitude when it made a steep left descending turn. The airplane completed about a 180o turn back in the direction of the airport as it descended in a wings level attitude below the terrain and out of the cameras view. AIRCRAFT INFORMATIONThe airplane was purchased by the pilot in September 2017. The airplane's most recent maintenance logbook entries were inconsistent and contained date corrections. The airplane's most recent logbook entries in the airframe, engine, and propeller logbooks referenced an annual inspection. The propeller logbook indicated the annual inspection was completed on August 17, 2017, at a tachometer time of 176.9 hours. The annual inspection in the engine logbook was dated September 18, 2017, at a tachometer time of 176.9. The airframe logbook indicated the annual inspection was completed on August 17, 2017; however, the date was darkened with unreadable numbers underneath. The previous maintenance entry in the logbooks indicated an annual inspection was completed on June 16, 2010, at a tachometer time of 149.7 hours and a total airframe time of 2,474.5 hours. The mechanic, who worked on the airplane the day before the accident, reported that the airplane had quite a few maintenance issues, however, he completed a few items that the pilot wanted fixed. He replaced some side paneling and cowling, secured the left exhaust stack, and helped find the source of an oil leak. When the engine was running to find the oil leak, the mechanic noted that the engine was not running particularly well. In addition, he noted that the throttle was only going to about 3/4 power despite the throttle lever being full forward. He observed that the oil leak was coming from the oil pressure line, so he capped the line. Since he did not have any oil lines with him, he informed the pilot that he could not fly until after he replaced the line the next day (the day of the accident). The pilot appeared unhappy about this because he needed to fly to a nearby airport, but he did not elaborate why. The mechanic noted that he did not record a maintenance logbook entry because the maintenance had not been completed at the time of the accident. AIRPORT INFORMATIONThe airplane was purchased by the pilot in September 2017. The airplane's most recent maintenance logbook entries were inconsistent and contained date corrections. The airplane's most recent logbook entries in the airframe, engine, and propeller logbooks referenced an annual inspection. The propeller logbook indicated the annual inspection was completed on August 17, 2017, at a tachometer time of 176.9 hours. The annual inspection in the engine logbook was dated September 18, 2017, at a tachometer time of 176.9. The airframe logbook indicated the annual inspection was completed on August 17, 2017; however, the date was darkened with unreadable numbers underneath. The previous maintenance entry in the logbooks indicated an annual inspection was completed on June 16, 2010, at a tachometer time of 149.7 hours and a total airframe time of 2,474.5 hours. The mechanic, who worked on the airplane the day before the accident, reported that the airplane had quite a few maintenance issues, however, he completed a few items that the pilot wanted fixed. He replaced some side paneling and cowling, secured the left exhaust stack, and helped find the source of an oil leak. When the engine was running to find the oil leak, the mechanic noted that the engine was not running particularly well. In addition, he noted that the throttle was only going to about 3/4 power despite the throttle lever being full forward. He observed that the oil leak was coming from the oil pressure line, so he capped the line. Since he did not have any oil lines with him, he informed the pilot that he could not fly until after he replaced the line the next day (the day of the accident). The pilot appeared unhappy about this because he needed to fly to a nearby airport, but he did not elaborate why. The mechanic noted that he did not record a maintenance logbook entry because the maintenance had not been completed at the time of the accident. WRECKAGE AND IMPACT INFORMATIONThe airplane came to rest on a road that was perpendicular to and about 100 ft below the runway. The first identified point of impact were about 36-ft high powerlines next to the road. The powerlines were severed. The wreckage debris path was scattered about 325 ft eastward along the road starting near the severed powerlines and ending at the main wreckage. The debris path began with parallel slash marks that were along the right lane of traffic. A gouge was in the centerline of the roadway, followed by a 4-ft-wide and 12-ft-long stretch of disturbed concrete. Included in this area were two distinct propeller blade marks, one of which was distinctly curved. Continuing along the debris path were small fragments of blue glass, sheet metal, plexiglass, and engine components scattered along the roadway. About 35 ft before the main wreckage was half of the upper cowling along with fragments of cylinder. The engine and most of the remaining engine cowling came to rest in the dirt along the right side of the roadway about 21 ft prior to the main wreckage. The main wreckage came to rest upside down and was heavily burned. The cabin area was destroyed by thermal damage. The inboard portion of the left wing was thermally damaged and not present. The right wing was bent aft towards the empennage. The inboard portion of the wing exhibited heavy thermal damage and was mostly melted; the outboard portion also exhibited heavy thermal damage. The aft fuselage was melted. The empennage was mostly intact. Postaccident examination of the airframe and engine revealed no anomalies that would have precluded normal operations. Visual examination of the engine revealed no obvious signs of catastrophic engine failure. The two blade, variable pitch propeller, remained attached to the crankshaft spline and was properly secured. Both propeller blades remained within the propeller hub and both blades displayed impact damage signatures. Blade #1 displayed significant S-bending deformation, twisting deformation, leading edge gouging, and chordwise scratches at the blade tip. Blade #2 displayed minor aft bending deformation, significant tip curling deformation, and chordwise scratches at the blade tip. The propeller was rotated by hand and continuity was established throughout the engine. All cylinders exhibited thumb compression and suction, with the exception of the No. 5 cylinder, which exhibited significant impact-related damage. The oil pressure indicating line was capped off. The magnetos were removed from the engine and spark was produced when rotated. The fuel pump was disassembled, and no anomalies were noted with the internal components. Flight control continuity was established throughout the airframe. The airplane's spinner and fragments of spinner bulkhead were located in the grass next to the departure end of runway 21. The spinner bulkhead was found separated into several pieces; some of the screws remained attached to the spinner and were undamaged, however, a majority of the screw holes were ripped. The fractures in the spinner bulkhead pieces were located across rivets or rivet holes. Metallurgical examination indicated that each fracture surface showed crack arrest marks, consistent with progressive crack growth, which was identified as fatigue cracking. MEDICAL AND PATHOLOGICAL INFORMATIONThe San Bernard County Coroner, San Bernardino, California performed an autopsy on the pilot. The pilot's cause of death was multiple blunt force injuries with inhalation of combustible products and thermocutaneous burns. The FAA's Forensic Sciences Laboratory performed toxicology testing on liver and muscle tissue samples. The testing identified tramadol and its metabolite O-desmethyltramadol as well as meprobamate in the available tissues. Tramadol is an opiod pain medicine available by prescription as a Schedule IV controlled substance. It carries warnings for the risk of addiction with its use, and increased risk of seizures. Meprobamate is a prescription tranquilizer available by prescription as a Scheduled IV controlled substance used to treat anxiety. Both medications carry the warnings that they may impair the mental and/or physical abilities required for performance of potentially hazardous tasks such as driving or operating machinery. Both of these are considered impairing and carry specific warnings about their use in combination.