History of Flight
On June 15, 2018, about 1700 Pacific daylight time, a Beech A35 airplane, registration N580B, was destroyed in an accident in Hesperia, California. The pilot and passenger were fatally injured. The flight was operated under 14 Code of Federal Regulations Part 91 as a personal flight.
A witness near the south end of the airport reported that the takeoff appeared routine. The witness later observed the airplane traveling in the opposite direction from departure at an altitude near powerline level. He then saw a fireball about 10 ft above the airplane before it struck the ground in a nose-low attitude with wings vertical. The airplane cartwheeled before coming to rest.
Another witness, located in a parking lot southwest of the departure runway end, reported that the airplane's climb seemed normal, but something detached from the airplane near the end of the runway. The airplane climbed to about 800 ft, then the nose dropped and it executed a "radical left turn." Following the turn, the wings appeared vertical and the airplane lost about 400 ft. It leveled and seemed to head back toward the airport, but the nose remained low. The airplane then turned right and appeared to align with a road before disappearing.
An off-airport video captured the initial climb. The airplane climbed to an undetermined altitude, then made a steep left descending turn. It completed approximately a 180° turn back toward the airport while descending in a wings-level attitude below the terrain, exiting the camera's view.
Aircraft Information
The airplane was purchased by the pilot in September 2017. The most recent maintenance logbook entries were inconsistent and contained date corrections. The airframe, engine, and propeller logbooks referenced an annual inspection. The propeller logbook showed the annual inspection was completed on August 17, 2017, at a tachometer time of 176.9 hours. The engine logbook annual inspection was dated September 18, 2017, also at tachometer time 176.9. The airframe logbook had the annual inspection dated August 17, 2017, but the date was darkened with unreadable numbers underneath. The previous logbook entry indicated an annual inspection on June 16, 2010, at tachometer time 149.7 hours and total airframe time of 2,474.5 hours.
The mechanic who worked on the airplane the day before the accident reported multiple maintenance issues. He completed a few items requested by the pilot, including replacing some side paneling and cowling, securing the left exhaust stack, and locating an oil leak source. While running the engine to find the leak, the mechanic noted the engine was not running well and that the throttle only reached about 3/4 power despite the lever being full forward. He observed the oil leak originated from the oil pressure line and capped it. Lacking replacement oil lines, he instructed the pilot not to fly until the line was replaced the following day. The pilot appeared unhappy about the delay but did not explain why. The mechanic noted no logbook entry was made because the maintenance was incomplete at the time of the accident.
Wreckage and Impact Information
The airplane came to rest on a road perpendicular to and about 100 ft below the runway. The first identified impact point was approximately 36-ft high powerlines adjacent to the road; the powerlines were severed.
The debris path extended about 325 ft eastward along the road from the severed powerlines to the main wreckage. The path began with parallel slash marks in the right traffic lane. A gouge was found in the roadway centerline, followed by a 4-ft-wide, 12-ft-long area of disturbed concrete containing two distinct propeller blade marks, one with a distinct curve. Small fragments of blue glass, sheet metal, plexiglass, and engine components were scattered along the road.
About 35 ft before the main wreckage, half of the upper cowling and cylinder fragments were found. The engine and most remaining cowling came to rest in the dirt on the right side of the road about 21 ft from the main wreckage. The main wreckage came to rest inverted and heavily burned; the cabin area was destroyed by thermal damage. The inboard portion of the left wing was thermally damaged and absent. The right wing was bent aft toward the empennage, with heavy thermal damage and melting inboard, and heavy thermal damage outboard. 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 inspection of the engine showed no obvious signs of catastrophic failure. The two-blade, variable-pitch propeller remained attached to the crankshaft spline and was properly secured. Both blades displayed impact damage: Blade #1 had significant S-bending, twisting, leading edge gouging, and chordwise scratches at the tip; Blade #2 had minor aft bending, significant tip curling, and chordwise scratches. Hand rotation of the propeller established continuity throughout the engine. All cylinders exhibited thumb compression and suction except the No. 5 cylinder, which had significant impact damage. The oil pressure indicating line was capped. The magnetos produced spark when rotated. The fuel pump disassembly showed no internal anomalies. Flight control continuity was established throughout the airframe.
The spinner and fragments of spinner bulkhead were located in the grass near the departure end of runway 21. The bulkhead was separated into several pieces; some screws remained attached and undamaged, but most screw holes were torn. Fractures in the bulkhead pieces occurred across rivets or rivet holes. Metallurgical examination showed each fracture surface had crack arrest marks consistent with progressive crack growth identified as fatigue cracking.
Medical and Pathological Information
The San Bernardino County Coroner performed an autopsy on the pilot, determining the cause of death as 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, identifying tramadol and its metabolite O-desmethyltramadol, as well as meprobamate. Tramadol is an opioid pain medicine, a Schedule IV controlled substance with warnings for addiction risk and increased seizure risk. Meprobamate is a prescription tranquilizer, also a Schedule IV controlled substance used to treat anxiety. Both medications carry warnings that they may impair mental and/or physical abilities required for hazardous tasks such as driving or operating machinery and are considered impairing, especially in combination.