On September 3, 1995, at 1030 central daylight time, a Morrow Starduster I, N46565, piloted by a commercial pilot, was destroyed during a collision with the ground while in a witness reported inverted spin. Visual meteorological conditions prevailed at the time of the accident. The personal 14 CFR Part 91 flight was not operating on a flight plan. The pilot was fatally injured. The flight departed Ottawa, Kansas, exact time unknown. According to the witnesses the pilot had been practicing for an aerobatic show when the airplane entered the inverted spin. Other witnesses reported the airplane did a hammerhead stall then entered the inverted spin. They said N46565's engine decreased and increased its RPM two to four times before colliding with the ground. A member of an aerobatic association the accident pilot belonged to said the hammerhead stall was entered between 2,500 and 3,000 feet above the ground. According to this witness, the airplane's engine was at full power during the inverted spin's five of the seven turns. He said the last two turns were accomplished with reduced power. During the on-scene investigation the NTSB was represented by Federal Aviation Administration (FAA) Principal Maintenance Inspector (PMI). He interviewed one witness who spoke with the pilot by radio during the inverted spin maneuver. The witness, according to the PMI, had told the pilot to reduce N46565's power several times before it collided with the ground. The witness said the pilot had trouble doing the hammerhead stall during his practice sessions. He said the pilot did four hammerhead stalls before the one that lead to the accident. The PMI reported no airframe, control, engine anomalies that would have affected N46565's performance. He said the propeller blades were straight, one of which was buried about 4 to 6 inches in the ground. The PMI said he did not observe any skid marks made by N46565's ground collision. According to the pilot's logbook, his last flight in the Starduster I airplane (N46565) was on April 8, 1995. His logbook showed he flew this airplane 7.2 hours during April 1, 7, and 8, 1995. There were no other logbook entries for this airplane during 1995. The logbook showed the flight before the accident flight was made in a Bellanca 7ECA Citabria on August 12, 1995. The flight is shown as a 9.3 hour cross country flight. The logbook showed the pilot flew the Bellanca 7ECA 14.7 hours between February 16 and August 12, 1995. The autopsy on the pilot was conducted by the Franklin County, Kansas, Coroner's Office on September 4, 1995. The FAA Civil Aeromedical Institute's toxicological report was negative for drugs, carbon monoxide, cyanide, and volatiles.