On August 4, 2001, at 1400 mountain daylight time, a Beech A35 single-engine airplane, N8431A, sustained substantial damage during a wheels-up landing on runway 21 at the Moab Municipal Airport, near Moab, Utah. The private pilot and his two passengers were not injured. The cross country flight was operated under Title 14 Code of Federal Regulations Part 91. The flight originated from Santa Fe, New Mexico, with a refueling stop made in Farmington, New Mexico. The flight departed Farmington at 1245, with Moab as its final destination. Visual meteorological conditions prevailed throughout the area for the personal flight for which a flight plan was not filed. The airport manager was in an another airplane in the traffic pattern at the airport when the accident occurred. He reported that the accident airplane's landing looked "normal" until the airplane "went off the runway to the right." When he landed his airplane, he "could see there was no gear underneath" the accident airplane. He assisted in moving the accident airplane to a hangar. When the accident airplane was lifted up, he observed the pilot enter the cockpit and lower the landing gear. He reported that the landing gear "came down under its own power after the gear doors were pried out of the way." Post-accident examination of the airplane by an FAA inspector revealed structural damage to the belly. Examination of the asphalt surface of runway 21 by the FAA inspector revealed scrape marks on the runway which correlated to the airplane's main landing gear doors. No tire marks were noted on the 7,100 foot runway prior to the scrape marks. The pilot of the airplane sent a letter to the NTSB investigator-in-charge (IIC) on August 23, 2001. The letter stated that he did not believe that the event was an accident, and therefore, he did not complete and return the Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1/2) previously sent to him by the IIC. On August 30, 2001, the IIC sent a registered letter to the pilot asking him again to return a completed NTSB Form 6120.1/2. The pilot did not respond.