History of Flight
On January 12, 2017, between 1100 and 1200 central standard time, an experimental, amateur-built Steen Skybolt airplane, registration N94RG, collided with terrain after a loss of control near Era, Texas. The pilot, who was the sole occupant and owner, was fatally injured, and the airplane sustained substantial damage. The flight was conducted as a 14 Code of Federal Regulations Part 91 personal flight. Visual meteorological conditions prevailed, and no flight plan had been filed. The flight departed from the pilot's private grass airstrip, located less than 1/2 mile from the accident site.
A witness reported hearing an airplane "flying aerobatics" and heard the engine "cycling under load as they do in airshows." He observed the airplane in a hammerhead climb (climbing straight up), after which it entered a slow, spiraling descent straight down. During the descent, the witness did not hear engine noise. The airplane made about four spirals before disappearing behind rising terrain. The witness stated that no attempt to recover from the descent was apparent.
Pilot Information
The pilot held an airline transport pilot certificate with multiengine and single-engine airplane ratings; single-engine operations were limited to commercial privileges. He was issued a first-class medical certificate on March 29, 2016, and reported a total of 2,250 hours of civil flight experience. The number of hours flown in the accident airplane could not be determined.
Aircraft Information
The experimental, amateur-built, open-cockpit biplane was manufactured in 1990. It was equipped with a six-cylinder Lycoming IO-540-B1A5 engine, serial number L-634-48, rated at 290 horsepower at 2,575 rpm. The airplane was purchased by the pilot around September 2016, though the registration still reflected the previous owner. It was kept in a hangar and operated from the pilot's private grass airstrip.
Meteorological Information
Surface weather observations from Denton Enterprise Airport (DTO), 20 nautical miles south of the accident site, reported the following conditions: at 1053, wind from 190° at 9 knots, visibility 10 miles, broken ceiling at 4,000 ft, temperature 22°C, dew point 17°C, altimeter 30.10 inHg. At 1153, wind from 220° at 10 knots, visibility 10 miles, broken ceiling at 2,600 ft, overcast at 4,500 ft, temperature 22°C, dew point 16°C, altimeter 30.09 inHg. At 1235, wind from 341° at 14 knots, visibility 10 miles, broken ceilings at 2,400 ft and 3,300 ft, overcast at 4,700 ft, temperature 15°C, dew point 8°C, altimeter 30.09 inHg; a wind shift occurred at 1215.
Wreckage and Impact Information
The wreckage was located in a pasture about 1,100 ft from the departure end of the north runway on a magnetic heading of 350°. Damage indicated the airplane collided with terrain at about a 45°-nose-down attitude. The engine compartment, fuselage, wings, and empennage exhibited crushing and buckling, but the airplane remained intact. No postimpact fire occurred. Flight control continuity was confirmed from all surfaces to cockpit controls. Elevator trim continuity was also confirmed.
One propeller blade was bent backward about midspan with minimal damage on its chambered surface and flat side; the tip exhibited abrasion and nicks. The propeller hub was found embedded 14 inches in soft clay soil. The second blade was twisted with extensive chordwise scratching and gouges. Engine examination revealed drive train continuity, and all six pistons moved. The top spark plugs appeared normal and nearly new. The left magneto produced spark on all towers; the right magneto was damaged and produced no spark. The fuel servo had residual fuel and was broken at the throttle plate. The engine rpm gauge indicated 2,450 rpm with 407.86 hours recorded. The airspeed indicator needle was found at 338 knots. The g-meter needles moved freely, with indicators showing +10 and -5 gs. These instruments were sent to the NTSB Materials Laboratory for examination.
Medical and Pathological Information
An autopsy performed by the Dallas County Institute of Forensic Sciences determined the cause of death as blunt force trauma and the manner as an accident. Toxicological testing by the FAA's Bioaeronautical Sciences Research Laboratory was negative for all tested substances.
Tests and Research
The NTSB Materials Laboratory examined the engine rpm gauge, airspeed indicator, and g-meter. No impact marks were observed on the gauge or indicator faces. The g-meter's internal parts moved freely, and its needles reset to original positions when the reset button was pressed; it appeared operational.