HISTORY OF FLIGHT On July 24, 2010, at 1120 eastern daylight time, an experimental, amateur built, Nadig, Avid Aircraft Aerobatic, N579PN, impacted terrain shortly after takeoff from the Venango Regional Airport (FKL), Franklin, Pennsylvania. The pilot/owner and pilot rated passenger were killed, and the airplane incurred substantial damage. Visual meteorological conditions prevailed and no flight plan was filed. The airplane was operated by a private individual, under the provisions of 14 Code of Federal Regulations Part 91, as a personal flight. A witness stated to the responding Federal Aviation Administrator (FAA) inspector that he observed the airplane conducted three touch and go landings from runway 21, in a left traffic pattern before the accident. Another witness stated that he heard the engine surging (revving up and down) and then the sound of impact behind his home. PERSONNEL INFORMATION The pilot/owner, seated in the left seat, held a private pilot certificate, with a rating for airplane single engine land. The pilot’s last medical certificate was issued on October 27 of 2008; a third-class; with must wear lenses for distant and possess glasses for near vision limitations. He reported a total of 936 flight hours at that time. The pilot rated passenger, seated in the right seat, held a private pilot certificate, with ratings for airplane single engine land and instrument airplane. The pilot’s last medical certificate was issued on April 4 of 2007; a third-class; with must wear lenses for near and distant vision, and not valid for any class after limitations. He reported a total of 4,640 flight hours at that time. AIRCRAFT INFORMATION The amateur built airplane, serial number 579, was issued an experimental airworthiness certificate on October 25, 1990. The airplane was powered by a Rotax, 582, auto fueled, liquid cooled, 65 horsepower rated engine. The airplane, and engine, last inspection was May 1, 2010 and had a total of 188 hours at that time. The pilot/owner purchased the airplane on May 7, 2010. METEOROLOGICAL INFORMATION The FKL, July 24, 2010, 1115 automatic surface weather observation was: wind variable from 230 to 290 degrees at 7 knots, visibility 10 miles, clouds broken from 1,700 to 12,000 feet above ground level, temperature 27 degrees Celsius ( C ), dew point temperature 23 degrees C and altimeter 30.04 inches of mercury. WRECKAGE AND IMPACT INFORMATION The FAA inspector stated that the accident site was about ¾ mile and east of the departure end of the runway in a wooded area behind a residence. The airplane impacted trees as it was flying east before descending, impacting the ground, and coming to rest flat. Flight control continuity was established and all flight control surfaces where located on the airplane. The tail section came to rest under the right wing and the cockpit area stayed intact. One of the 2 blades on the propeller was bent aft. Engine control lever continuity was established. The engine was rotated and thumb compression was established. Evidence of fuel was observed in the airplane’s fuel system and at the accident site. The engine was retained for further examination. TEST AND RESEARCH The engine was examined and run at the Rotax facility in Canada with Transportation Safety Board of Canada oversight. The engine external examination revealed the intake manifolds were modified with non standard material. The spark plugs and ignition wires were of non standard components. The modified intake manifolds were made of different types of material, which were secured by adhesive tape. The carburetors were inspected, which deposits, of unknown substance, on the floats and at the bottom of the carburetor bowl were observed. The engine test run revealed a blocked idle jet in the one of the two carburetors preventing normal operation. The engine would run only momentarily by spraying raw fuel directly into the carburetors. Once the blockage was removed from the idle jet, the engine started and ran to normal limits without any further anomalies. MEDICAL AND PATHOLOGICAL INFORMATION The forensic pathologist in Erie, Pennsylvania, conducted a postmortem examination on the pilot; cause of death was blunt force trauma. The FAA Civil Aeromedical Institute (CAMI) conducted toxicology testing on specimens from the pilot and passenger. No carbon, cyanide, and ethanol were detected; ranitidine was detected in the passenger.