HISTORY OF FLIGHT On July 26, 2005, about 1600 central daylight time, N6327T, registered as a North American F-51D airplane, piloted by a private pilot, was destroyed on impact with terrain while maneuvering near Malone, Wisconsin. The personal flight was operating under 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed at the time of the accident. No flight plan was on file. The pilot sustained fatal injuries. The local flight departed from the Wittman Regional Airport (OSH), near Oshkosh, Wisconsin, about 1525. The airplane departed OSH with three other airplanes as a flight of four airplanes to perform the missing man demonstration at the air show at OSH. The accident airplane was the number 4 airplane in the flight. According to the lead airplane's pilot, the flight of four was holding in a V-shaped formation on the east side of Lake Winnebago at 2,000 feet above ground level. The flight leader asked the air show's air boss how much longer they would have to hold before the flight's performance could start. The air boss stated it would be about another 15 minutes. The flight leader called a formation change to four airplanes in trail and the flight performed a ground reference maneuver called lazy eights. During the lazy eight maneuver, the first three members of the flight realized that the no. 4 airplane was not in trail and began a search for it. A witness stated: On about 4:00 to 4:15 PM I observed 4 airplanes coming from the west side of Lake Winnebago and they started to do some steep turns following the shore line. [Three] of the airplanes held a tight flight pattern and did steep turns [and] the 4th aircraft was substantially further behind the 3 planes. I noticed this when they came across the lake and also when they started their maneuvers. The plane kept far behind [and] followed the first 3 planes maneuvers. When the 1st, 2nd [and] 3rd planes did a steep turn and headed east then pulled up and at the top of the pull out they rolled the airplanes over/turn [and] continued east. The 4th plane followed but on top of his pull up and rolled slower than the 3 previously. The plane never finished the roll completely [and] tucked under [and] flew [inverted] to the west instead of east following the 3 planes. The plane then turned to the north trying to recover but all I heard was an acceleration of speed [and] the plane going straight down until it went thud and quit. The other 3 planes kept flying for 5 minutes or so ... . PERSONNEL INFORMATION The pilot held a private pilot certificate with single engine land, multi-engine land, and instrument ratings. The pilot held a third class medical certificate with a limitation for corrective lenses. That medical certificate was dated April 14, 2004. According to Federal Aviation Administration (FAA) aeromedical records, the pilot reported having 3,650 total flying hours on the application for that medical certificate. The pilot also reported having flown 35 hours in the six months prior to that medical. Other than the accident pilot, the last reported pilot to fly the accident airplane, in July of 2004, stated that the airplane had no mechanical problems. He further stated: I also had flown aerobatic dual with [the accident pilot] several years prior. No problems recalled. I did have a visit with [him] the Friday prior to the accident. He noted his concern about obtaining a medical renewal the next expiration. He was concerned about his deteriorating vision. He did say he had a schedule to visit the Mayo Clinic. No other concerns were discussed. AIRCRAFT INFORMATION N6327T, a North American F-51D, Mustang, serial number 44-74417A, was an all-metal, laminar flow, low-wing monoplane. The airplane's ailerons, elevators, and rudder were conventionally operated by a control stick and rudder pedals. The airplane was powered by a twelve-cylinder, overhead cam, liquid cooled, V-type, supercharged, Rolls Royce V-1650-7 engine, serial number V-330830. According to copies of the aircraft's logbook entries, the last annual inspection was performed on July 7, 2005. The aircraft had accumulated a total time of 2,208.4 hours at the time of that annual inspection. The engine had accumulated 421.2 hours since a major overhaul at the time of that annual inspection. METEOROLOGICAL INFORMATION At 1553, the recorded weather at the Fond Du Lac County Airport, near Fond Du Lac, Wisconsin, was: Wind 350 degrees at 8 knots; visibility 10 statute miles; sky condition few 2,700 feet, broken 3,700 feet, overcast 7,500 feet; temperature 22 degrees C; dew point 15 degrees C; altimeter 29.89 inches of mercury. WRECKAGE AND IMPACT INFORMATION An on-scene investigation was conducted. The airplane came to rest in a field West of US Highway 151, near Calumetville, Wisconsin, at latitude 43 degrees 55.959 minutes N and longitude 88 degrees 18.521 minutes W. The airplane's fuselage, wings, and engine were found crushed rearward. The propeller was found impacted in terrain about five feet below grade. Two of the propeller blades were separated from the propeller hub. The empennage was separated from the fuselage forward of the tailwheel. The empennage came to rest inverted. The smell of aviation gasoline was present and vegetation around the wreckage exhibited blight. The wreckage was removed to a sheltered area for examination. Control cable continuity was established from the flight controls to the cabin area of the fuselage. All observed breaks in control cables exhibited a broom straw appearance. The propellers were examined and the blades' leading edges exhibited nicks. A liquid consistent with aviation gasoline was found in a fuel valve. The engine was crushed and deformed. The crankshaft was intact and deformed in an accordion shape. No pre-impact anomalies were found with the engine or airframe. MEDICAL AND PATHOLOGICAL INFORMATION The Fond du Lac County Coroner's Office arranged for an autopsy to be performed on the pilot. The FAA Civil Aeromedical Institute prepared a Final Forensic Toxicology Accident Report. The report was negative for the tests performed. ADDITIONAL INFORMATION The FAA was a party to the investigation. The wreckage was released to a family member.