On April 21, 1997, at approximately 1700 central daylight time, a Cessna 150F, N3101X, was substantially damaged following a hard landing at the David Jay Perry Airport, near Norman, Oklahoma. The private pilot and his passenger were not injured. The airplane was owned and operated by Av8ter Services, Ltd. of Norman, Oklahoma, as a Title 14 CFR Part 91 personal flight. Visual meteorological conditions prevailed for the local flight which originated approximately 45 minutes before the accident. No flight plan had been filed for the flight. During a telephone interview with the investigator-in-charge, the pilot stated that he was landing on runway 31 when "something happened," and the airplane landed hard. On his written statement, the pilot stated that "while over the touchdown zone in ground effect, a sudden and dramatic increase in sink rate occurred." The pilot increased the throttle, "but due to the proximity to the runway even though the sink rate appeared to decrease, the aircraft contacted the runway on the landing gear." The nose gear folded back under the airplane and subsequently damaged the fire wall, structural components behind the fire wall, and the belly skin.