History of Flight
On September 9, 2017, at about 1413 Pacific daylight time, a Raytheon Aircraft Company G36 airplane, registration N7215J, sustained substantial damage when it impacted terrain in Benicia, California, about 9 miles northwest of Buchanan Field Airport (CCR), Concord, California. The private pilot and passenger were fatally injured. The airplane was registered to Vallee Development Corporation and was being operated as a personal flight under 14 CFR Part 91. Visual meteorological conditions prevailed, and no flight plan was filed. The flight originated from CCR at about 1406, destined for California Redwood Coast-Humboldt County Airport in Arcata-Eureka.
Radar data indicated the airplane departed CCR on a northwest heading, consistent with its intended destination. The first few minutes showed the airplane climbing. Surface winds were about 330° at 12 knots, providing a headwind during climb. The airplane climbed to a maximum altitude of about 2,500 ft msl. During the last two minutes, ground speed began to decrease near level-off altitude. At 1412:29, at 2,400 ft msl, ground speed was 69 knots; at 1412:32, still at 2,400 ft msl, ground speed was 56 knots. At 1412:42, the last radar return, ground speed was 55 knots and altitude had decreased by 600 ft to 1,800 ft msl, with a descent rate of about 3,600 ft per minute. The radar also showed a sharp right turn.
The FAA issued an alert at 1926 after a family member reported the airplane overdue. The Civil Air Patrol located the wreckage the next morning near the top of a hillside in Benicia.
Pilot Information
The pilot held a private pilot certificate with an airplane single-engine land rating, a high-performance endorsement (March 18, 2003), and a complex airplane endorsement (May 8, 2015). He held a third-class medical certificate issued May 6, 2017, with no limitations. His logbook showed about 528 hours total flight time, mostly in Piper PA-28 and Cessna C-182 airplanes. He had logged 3 flights (2.7 hours total) in the accident airplane, all in July 2017, as pilot-in-command with no dual time.
The passenger held a student pilot certificate and a third-class medical certificate dated February 21, 2003, which had expired and was not renewed; the passenger did not obtain a pilot's license.
Aircraft Information
The Raytheon G36 is a six-seat, low-wing, retractable-gear airplane manufactured in 2006, a variant of the Beechcraft Bonanza 36. It was powered by a Continental IO-550-B39B engine with a three-bladed constant-speed propeller. The engine was modified with a Tornado Alley Turbo turbonormalizer system (Supplemental Type Certificate SA5223NM), installed September 19, 2008. The most recent airframe annual inspection was completed December 3, 2016 (Hobbs time about 1,536 hours); the most recent engine inspection was August 14, 2017 (Hobbs time about 1,600 hours).
According to the Pilot's Operating Handbook, stall speed at 3,600 lbs and flaps up was 68 KIAS at 0° bank and 73 KIAS at 30° bank. The Airplane Flight Manual Supplement for the turbonormalizer increased maximum takeoff gross weight to 4,000 lbs and stated performance is equal to or better than the original, but noted decreased rate of climb (up to 13%) and increased stall speeds (up to 7%) at higher weights. The airplane's most recent weight and balance form was not located; paperwork from April 2017 listed maximum gross weight of 4,000 lbs and useful load of 1,209 lbs.
Meteorological Information
The 1353 weather observation at CCR (about 20 minutes before the accident) reported: wind 330° at 12 knots, visibility 10 statute miles, sky clear, temperature 30°C, dew point 17°C, altimeter 29.96 inches of mercury.
Wreckage and Impact Information
The airplane came to rest on top of a mesa at an elevation of about 587 ft msl, on flat terrain with dense vegetation. The fuselage was upright on a magnetic heading of about 125°. The fuselage and engine were contained within an area about 8 ft long, 4 ft wide, and 1 ft deep; the engine was partially buried. All major structural components were within the debris area. Damage and ground signatures were consistent with a wings-level, nose-down, high-angle impact.
Both wings remained attached but sustained significant compression damage, with leading edges crushed aft to the spar. Fuel bladders were ruptured, and fragments scattered about 170 ft forward. Wing tip tanks showed compression damage corresponding to about a 60° nose-down impact. Landing gear and flaps were retracted. Flight control continuity was confirmed. Elevator trim was about 2° to 3° tab up.
The empennage and cabin roof had been removed by first responders; the empennage separated about 2 ft forward of the vertical stabilizer. The rudder and elevators remained attached. The engine sustained impact damage and separated from mounts. The propeller separated at the crankshaft; two of three blades were bent aft mid-span and two exhibited twisting. A hole in the crankcase between cylinders No. 1 and 3 was consistent with impact forces. Accessories were damaged.
Examination of the airframe and engine at Plain Parts facility in Pleasant Grove, California, revealed no evidence of preimpact mechanical malfunctions or failures that would have precluded normal operation.
Additional Information
The FAA's Handbook of Aeronautical Knowledge explains that groundspeed is true airspeed (TAS) adjusted for wind. At the last radar return (altitude about 2,500 ft, groundspeed 55 knots), adjusting for the 12-knot headwind gives a TAS of about 67 knots. Using atmospheric data, calibrated airspeed (CAS) was estimated about 5 knots slower than TAS, so CAS about 62 knots.
The FAA's Airplane Flying Handbook notes that transition to a complex or high-performance airplane can be demanding and should be accomplished through structured training with a qualified instructor.
Six SD data cards from the Garmin G1000 system were found but contained no pertinent data. An engine temperature sensor had no non-volatile memory for recording.
Medical and Pathological Information
An autopsy of the pilot by the Solano County Sheriff's Office determined the cause of death as multiple blunt force injuries. Toxicology testing for the pilot and passenger was negative for tested drugs. Ethanol and propanol were detected in the pilot's muscle and liver samples; ethanol was detected in the passenger's brain and muscle samples. The presence of propanol and differing ethanol concentrations suggested the alcohol originated from postmortem sources rather than consumption.