HISTORY OF FLIGHT On July 23, 2010, at 2020 central daylight time, an experimental amateur-built Warth Classic Sport S-18, N216TB, sustained substantial damage when it impacted a cornfield after a loss of engine power shortly after takeoff from runway 16 (3,650 feet by 60 feet asphalt) at the Lincoln County Airport (Y14), Tea, South Dakota. The commercial pilot was fatally injured. The 14 Code of Federal Regulations Part 91 personal flight departed Y14 on a local flight. Visual meteorological conditions prevailed at the time of the accident. No flight plan was filed. A witness reported that he spoke to the pilot shortly before the accident. He stated that the pilot was going to fly the accident airplane on a maintenance test flight because he had recently installed a throttle body fuel injection system in place of the original carburetor. The pilot had also installed new engine baffles and a Vans RV-4 intake scoop. The witness observed the pilot conduct the pre-takeoff and engine run-up procedures. He reported that the engine hesitated and failed to run up to full RPM on the first attempt. The engine “went flat and lost RPM” on the second attempt. He reported that the third run-up was successful and the engine attained full RPM. He reported the takeoff roll was normal with the engine developing full power. The airplane rotated normally and climbed straight ahead to about 500 – 600 feet above ground level (agl). The airplane entered a left crosswind turn. The witness reported that he observed a “brief puff” of dark, black smoke coming from the exhaust. The airplane, which was now about 1/2 mile from the airport, started to lose altitude as it continued in a left turn. The airplane continued in a left bank until it was headed in a westerly direction. The witness stated, “The aircraft entered a full stall, probably 150 to 200 feet off the ground.” Another witness reported that the airplane entered a hard right turn after it had pitched up when it was about 100 to 150 feet agl. He reported that the airplane impacted a cornfield in a 50 to 60 degree nose down attitude, and it appeared that the left wing and nose of the airplane impacted the terrain first. PERSONNEL INFORMATION The pilot, age 31, held a commercial pilot certificate with single-engine and multi-engine airplane land with an instrument airplane rating. He held a second-class medical certificate that was issued in September 2009. The pilot’s logbook indicated that he had about 3,366 total flight hours and about 65 hours in make and model. The last recorded flight in the pilot’s logbook was made on November 18, 2009. AIRCRAFT INFORMATION The two-seat, low-wing, experimental amateur-built Warth Classic Sport S-18, serial number 245, was powered by a Lycoming O-320-D2A 180-horsepower engine and was equipped with a Sensenich propeller. The airplane’s maintenance logbook indicated that the airplane had about 123 total hours, and that the last conditional inspection was conducted on February 22, 2010. A Rotec Throttle Body Unit and regulator were installed on the engine, replacing the original carburetor. METEOROLOGICAL INFORMATION At 1956, the surface weather observation at the Joe Foss Field Airport, Sioux Falls, South Dakota, located about 8 miles north of the accident site, was: Wind 150 at 8 knots, visibility 10 miles, broken ceiling at 3,800 feet, temperature 28 degrees Celsius (C), dew point 23 degrees C, and altimeter 29.76 inches of Mercury. WRECKAGE AND IMPACT INFORMATION The airplane wreckage was located in a cornfield near the airport. The damage to the corn stalks and the impact to the wreckage were consistent with the airplane impacting the terrain inverted in about a 60 – 70 degree nose down attitude. The right wing was separated from the fuselage and found about 30 feet from the main wreckage. Federal Aviation Administration inspectors examined the wreckage at the accident site. The inspection of the airframe revealed no pre-impact anomalies. The engine was separated from the airframe for inspection. An Airframe and Powerplant (A&P) mechanic assisted with the engine inspection. The engine inspection revealed that both magnetos were broken and no testing could be performed. The number 2 cylinder was removed from the case and no internal damage to the drive train was noted. The compression was checked by rotating the crankshaft. Compression and suction were confirmed on the three remaining cylinders. Drive train continuity was confirmed. The mechanical fuel pump was broken in two pieces from the impact and could not be tested. There was fuel in the fuel line going to the regulator and fuel in the line between the regulator and the throttle body. All the control cables going to the throttle body were connected. The inspection of the propeller revealed that the blades were bent aft. No chordwise scoring or leading edge gouges or nicks were found on the blades The Rotec Throttle Body unit and regulator were sent to the National Transportation Safety Board’s investigator-in-charge for testing. The throttle body and regulator were visually inspected and installed on a recently overhauled Lycoming O-320 engine. The engine was on a test stand. There were no leaks to the throttle body. The engine was started and operated through the entire range of RPM’s. The engine ran smoothly at 1,500, 2,000, and 2,500 RPM. At 2,600 RPM and at 26 inches of manifold pressure, the engine started to sound slightly rough. There were no anomalies noted during the inspection and engine run. MEDICAL AND PATHOLOGICAL INFORMATION An autopsy of the pilot was conducted at LCM Pathologists, Sioux Falls, South Dakota, on July 24, 2010. The cause of death was multiple blunt trauma secondary to an airplane accident. The FAA Civil Aeronautical Institute prepared a Forensic Toxicology Fatal Accident Report, which indicated negative results for carbon monoxide, cyanide, and ethanol. 38.92 (ug/ml, ug/g) acetaminophen was detected in the urine.