On September 14, 1993, about 1055 hours Pacific daylight time, a homebuilt experimental R and K Special airplane, N115R, collided with terrain while on a timing run at the Reno National Air Races, Reno, Nevada. The airplane was destroyed and the commercial rated pilot received serious injuries. The pilot stated that he made a slight roll correction prior to the airplane pitching down and contacting the ground. Crew witnesses stated that: "Racer number 6 was the last biplane flying in the practice/qualification session. The pilot made several laps at a higher altitude. He then descended to what appeared to be the same altitude the previous biplanes had used to qualify. As the pilot approached the start/finish line, they observed a slight roll, a roll correction, and an immediate pitch down at about 20 degrees with wings level to ground impact." The pilot reported that witnesses told him that the airplane hit the ground tail first. He also stated that information provided by other race pilots indicated that the airplane encountered a severe windshear/whirlwind. The aircraft was examined by an FAA airworthiness inspector who reported that no preimpact mechanical malfunctions or failures were evident.