On August 23, 2007, about 1330 eastern daylight time, a Sukhoi SU-31 experimental airplane, N131BW, was destroyed during impact with terrain and a postcrash fire, near Markham, Virginia. The certificated commercial pilot was seriously injured. Visual meteorological conditions prevailed for the flight that departed Warrenton-Fauquier Airport (W66), Warrenton, Virginia, about 1300; destined for New Garden Airport (N57), Toughkenamon, Pennsylvania. A visual flight rules flight plan was filed for the personal flight conducted under 14 Code of Federal Regulations Part 91. According to the pilot's written statement, the airplane developed a fuel leak during cruise flight, and there was a strong fuel odor in the cockpit. The pilot became disoriented as to his location and altitude, while looking for the source of the fuel leak and searching for a suitable landing area. The pilot did not recall the actual impact. According to a Federal Aviation Administration (FAA) inspector, a nearby witness reported that visibility was low due to clouds. She heard the airplane approach from the south, and then heard it impacting trees before hitting the ground. The FAA inspector further stated that the state police and medivac helicopters could not respond due to the low ceilings, and all-terrain-vehicles were getting lost in the fog near the accident site. The airplane was consumed by fire, and the FAA inspector was unable to perform a wreckage examination or identify a fuel leak. The pilot held a commercial pilot certificate, with a rating for airplane single engine land. He did not have an instrument rating. The pilot reported a total flight experience of 5,400 hours; of which, 2,700 hours were in the same make and model as the accident airplane. The pilot did not report any simulated or actual instrument experience. The pilot also reported that he obtained a weather briefing via computer, and that the weather at the time of the accident, at Winchester Regional Airport (OKV), Winchester, Virginia, included an overcast ceiling at 2,400 feet and 7 miles visibility. Winchester Regional Airport was located about 15 miles northwest of the accident site, at an elevation of 727 feet msl. The reported weather at OKV, at 1320, was: wind calm; visibility 7 miles; overcast ceiling at 1,200 feet; temperature 22 degrees Celsius (C); dew point 20 degrees C; altimeter 30.15 inches of mercury. The elevation near the accident site was approximately 700 feet msl.