On September 20, 1997, at 1315 central daylight time, an Aerotek Pitts S-2A aerobatic biplane, N73EW, was destroyed following a loss of control while performing aerobatic maneuvers near San Marcos, Texas. The airline transport rated pilot, sole occupant of the airplane, was fatally injured. The airplane was registered to Kaimana Airshows Inc., of Ponca City, Oklahoma, and was being operated by the pilot under Title 14 CFR Part 91. Visual meteorological conditions prevailed for the aerobatic demonstration flight which originated from the San Marcos Municipal Airport approximately 15 minutes prior to the accident. The airplane was performing at the Sixth Annual Confederate Air Force Airshow at the San Marcos Municipal Airport (HYI). The airshow, titled "Gathering of Memories Airshow," was sponsored by the Central Texas Wing of the Confederate Air Force in Fort Worth, Texas. The airport manager stated that the accident occurred while the pilot was performing an aerobatic routine as part of the opening ceremonies of the airshow, which was attended by approximately 15,000 spectators. Witnesses at the airshow reported that prior to the accident the biplane had been performing an aerobatic routine for 12 to 15 minutes. The airplane made a high speed pass across the field from west to east at an estimated altitude of 200 feet AGL, followed by a near vertical climb to approximately 2,000 feet AGL. At that point the airplane was observed rolling inverted while on a westerly heading. The airplane was then observed rolling to the upright position, immediately performing a snap roll to the right, and then entering a spin. One of the witnesses, an aerobatic judge who was not judging the airshow, stated that "the pilot entered a snap roll maneuver with insufficient airspeed." Witnesses at the airport further reported that the factory built aerobatic biplane impacted in the infield area between runway 21 and the parallel taxiway, in a near level attitude while recovering from a spin. The witnesses further stated that the airplane "was traveling at a high rate of speed with a high rate of descent at the time of the impact." A video of the accident sequence was compiled from video tape segments provided by 4 separate news media organizations that were in attendance at the airshow. A copy of that video tape was provided to FAA representatives and is enclosed with this report. FAA inspectors who witnessed the accident stated that the airplane impacted the ground on a measured heading of 150 degrees. The ground scar at the initial point of impact was a gouge mark approximately 30 inches wide and 8 feet long. The airplane came to rest in the upright position approximately 60 feet beyond the initial point of ground impact, on a heading of 160 degrees. The FAA inspectors reported that flight control continuity was established to all flight controls, and an inventory of the airplane was conducted to ensure that all major components and flight controls were either still attached to the airframe or found within a 60 foot radius of the resting place of the airplane. All four wings remained attached to the fuselage. The damage to the leading edge of the lower right wing was far more pronounced that the damage incurred by the lower left wing. The right main landing gear was sheared off the fuselage and the left main landing gear collapsed and came to rest atop the leading edge of the left wing. The fuselage was buckled in two areas, aft of the rear cockpit, and aft of the engine firewall. All flight control surfaces remained attached to the wings and stabilizers. The constant speed propeller assembly remained attached to the propeller shaft, and both propeller blades remained attached to the propeller hub. Both propeller blades exhibited "S-type" bending and chordwise striations. Small portions of the tips were found missing from each blade. Witnesses reported that the engine was operating at a high power setting and the propeller was turning during the airplane's descent. The 4-cylinder Lycoming AEIO-360-A1A engine came to rest canted approximately 20 degrees to the right of the airframe centerline, and it remained partially attached to the airframe. The engine recording tachometer read 1,375 hours. There was no post-impact fire. There were no reported injuries to anyone on the ground. Examination of the airframe by the FAA inspectors at the site did not disclose any evidence of pre-impact mechanical failure or malfunction. The airline transport rated pilot had accumulated over 20,000 flight hours of which approximately 1,400 hours were in the accident airplane. At the time of his last flight physical examination on February 24, 1997, the pilot stated in the FAA application form that he had flown 200 hours in the preceding six months. His last medical certificate was issued with a waiver requiring the pilot to have available glasses for near vision. The pilot, who was wearing a flight helmet, was operating the airplane from the aft cockpit. The pilot was described by other airshow participants and friends as a "very safety conscientious pilot and a true perfectionist in all facets of his life." The pilot was reported to have performed in 17 airshows in 1996, and had performed in 3 airshows so far in 1997. His most recent airshow was performed at his home town of Ponca City. The pilot of the airplane was in radio contact with a temporary tower that was monitoring the airshow. No distress calls were received by the tower from the pilot of the accident airplane. An autopsy and toxicological tests were requested and performed. The autopsy was performed on September 9, 1997, at the Travis County Forensic Center, in Austin, Texas, by Elizabeth Peacock M.D., Deputy Medical Examiner. Toxicological tests were negative. The airplane was released to the owner's representative upon completion of the field portion of the investigation.