N110PX

HISTORY OF FLIGHTOn August 6, 2016, about 0820 central daylight time, an experimental amateur-built Wilson Bugatti-DeMonge 100P airplane, N110PX, impacted terrain shortly after takeoff from runway 35L at the Clinton-Sherman Airport (CSM), near Burns Flat, Oklahoma. The airline transport pilot was fatally injured, and the airplane was destroyed during impact and a subsequent postcrash fire. The airplane was registered to Le Reve Bleu LLC and was operated by the pilot as a 14 Code of Federal Regulations Part 91 test flight. Day visual meteorological conditions prevailed in the area about the time of the accident, and no flight plan was filed. The local flight was originating from CSM at the time of the accident.

A witness at the airport reported that the airplane lifted off the runway. During the initial climb, the airplane banked to the right and then to the left. The airplane's left bank increased, it descended nose down, and subsequently impacted terrain inverted. Review of a chase helicopter's video was consistent with the witness statements. PERSONNEL INFORMATIONThe 66-year-old pilot held a Federal Aviation Administration (FAA) airline transport pilot certificate with single-engine land, multi engine land, and instrument airplane ratings. He held a second-class FAA medical certificate issued on May 12, 2016. This medical certificate was issued with limitations: "Must wear corrective lenses. and Not valid for any class after 05/31/2017." The pilot reported on that medical certificate application 10,700 hours of total flight time and 25 hours of flight time in the previous six months. AIRCRAFT INFORMATIONN110PX was an experimental amateur-built, twin-engine, single-seat, tailwheel monoplane built as a replica of the Bugatti-DeMonge 100P, a 1930's era air racer that was never flown. There was only one original airplane produced, and the accident airplane was the first and only replica produced to the date of this report. According to airworthiness documents, the airplane was constructed to duplicate the original airplane's structure, systems, and dimensions. The accident airplane was powered by two Suzuki Hyabusa reciprocating, clutched motorcycle engines mounted in tandem aft of the cockpit. The engines drove two coaxial two-blade contra-rotating Hercules fixed-pitch wooden propellers. The forward engine was installed with the output drive shaft forward and was directly connected to the propeller reduction gearbox through universal joints and drive shafts on the left side of the fuselage. The rear engine was installed with the output drive shaft aft and was indirectly connected to the propeller reduction gearbox through a chain drive and sprockets that drove the drive shafts and universal joints on the right side of the fuselage. Both engine gearboxes were set in 6th gear and could not be changed. The propeller reduction gearbox was contained in a single housing with two separate drive trains to drive the forward and aft contra rotating propellers. The forward engine engaged the left gearbox drivetrain and drove the forward propeller. The aft engine engaged the right drivetrain and drove the aft propeller.

Engine throttle control was accomplished through two levers installed side-by-side on the left side of the cockpit with the left throttle lever controlling the forward engine and the right throttle lever controlling the aft engine. Engagement of the hydraulic clutches on the engines was accomplished independently by two levers mounted side-by-side on the right side of the cockpit. Each engine could be run without propeller movement until the respective clutch was engaged.

The airplane's maximum gross weight was listed as 2,939 pounds and its empty weight was 2,470 pounds. The airplane received its FAA Special Airworthiness Certificate in the experimental category on August 4, 2015. METEOROLOGICAL INFORMATIONAt 0753, the recorded weather at CSM was wind 040° at 9 knots, visibility 10 statute miles, sky condition clear, temperature 23° C, dew point 21° C, and altimeter 30.06 inches of mercury. AIRPORT INFORMATIONN110PX was an experimental amateur-built, twin-engine, single-seat, tailwheel monoplane built as a replica of the Bugatti-DeMonge 100P, a 1930's era air racer that was never flown. There was only one original airplane produced, and the accident airplane was the first and only replica produced to the date of this report. According to airworthiness documents, the airplane was constructed to duplicate the original airplane's structure, systems, and dimensions. The accident airplane was powered by two Suzuki Hyabusa reciprocating, clutched motorcycle engines mounted in tandem aft of the cockpit. The engines drove two coaxial two-blade contra-rotating Hercules fixed-pitch wooden propellers. The forward engine was installed with the output drive shaft forward and was directly connected to the propeller reduction gearbox through universal joints and drive shafts on the left side of the fuselage. The rear engine was installed with the output drive shaft aft and was indirectly connected to the propeller reduction gearbox through a chain drive and sprockets that drove the drive shafts and universal joints on the right side of the fuselage. Both engine gearboxes were set in 6th gear and could not be changed. The propeller reduction gearbox was contained in a single housing with two separate drive trains to drive the forward and aft contra rotating propellers. The forward engine engaged the left gearbox drivetrain and drove the forward propeller. The aft engine engaged the right drivetrain and drove the aft propeller.

Engine throttle control was accomplished through two levers installed side-by-side on the left side of the cockpit with the left throttle lever controlling the forward engine and the right throttle lever controlling the aft engine. Engagement of the hydraulic clutches on the engines was accomplished independently by two levers mounted side-by-side on the right side of the cockpit. Each engine could be run without propeller movement until the respective clutch was engaged.

The airplane's maximum gross weight was listed as 2,939 pounds and its empty weight was 2,470 pounds. The airplane received its FAA Special Airworthiness Certificate in the experimental category on August 4, 2015. WRECKAGE AND IMPACT INFORMATIONThe airplane wreckage was found about 1,900 ft and 335° from the departure threshold of runway 35L. The airplane came to rest inverted on an approximate 330° heading. A depression was observed in the ground about 110° and 23 ft from the wreckage. Sections of clear plastic were found in the depression and the surface of sections of the depression contained a blue color transfer consistent with the color of the airplane. The airplane, forward of its empennage, was discolored, deformed, and charred, with sections consumed by fire. The rudder's skin was consumed by fire. The lower section of the right main landing gear separated from its strut and the lower section was found resting on vegetation northwest of the main wreckage. Splintered wooden propeller blade fragments were found resting on the ground in the area around the wreckage.

An on-scene examination of the wreckage was conducted. The rudder control cables were traced from the rudder to the rudder pedals. The elevators' push/pull tubes were attached to the control arms for each elevator. Forward of the empennage, the elevator tubes were found to be consumed by fire. Sections of the aileron tubes were found to be consumed by fire outboard of the fuselage. However, outboard sections of the aileron's control tubes were found connected to each aileron. Control continuity for the elevators and ailerons could not be established due to the fire damage. The propulsion drivetrain was traced from the engines to the gearbox and propellers, and no preimpact anomalies were detected. There were no observed damage or witness marks to indicate that the chain and sprockets for the aft engine became disengaged under power. The engines sustained thermal damage. The engines could not be rotated by hand and their clutches were not examined on scene. However, no external indications of engine anomalies were observed. The propeller gearbox was intact but had sustained thermal damage and sooting. The propeller hub was attached and charred. A portion of the left driveshaft remained attached to the universal joint and the right drive shaft was separated from the universal joint. There were no external indications of gearbox anomalies observed. ADDITIONAL INFORMATIONExamination of the terrain from the accident site to one quarter mile north of the accident site revealed that a suitable field for an emergency landing was present there. MEDICAL AND PATHOLOGICAL INFORMATIONAn autopsy was performed on the pilot by the Office of the Chief Medical Examiner in Oklahoma City, Oklahoma, and toxicological samples were taken. The autopsy listed multiple blunt force injuries as the cause of death and accident as the manner of death.

The FAA Bioaeronautical Sciences Research Laboratory's Civil Aerospace Medical Institute (CAMI) prepared a Final Forensic Toxicology Accident Report on the samples taken during the autopsy. The report indicated that the samples sustained putrefaction and subsequently, in part, stated:

178 (mg/dL, mg/hg) Ethanol detected in Muscle

38 (mg/dL, mg/hg) Ethanol detected in Brain

N-Butanol detected in Muscle

Propanol (N-) detected in Muscle

Propanol (N-) detected in Brain

The CAMI description of Ethanol indicated that it is "primarily a social drug with a powerful central nervous system depressant. After absorption, ethanol is uniformly distributed throughout all tissues and body fluids. The distribution pattern parallels the water content and blood supply of each organ. Postmortem production of ethanol also takes place due to putrefaction processes, but vitreous humor and urine do not suffer from such production to any significant extent in r...