On July 26, 1998, about 1430 mountain daylight time (mdt), a Grumman American AA-5B, N4535P, piloted by a private pilot, was destroyed during a collision with trees, terrain and post-impact fire. Circumstances leading to the accident are unknown. The airplane was declared missing on July 26, 1998, and was found on August 1, 1998, Visual meteorological conditions prevailed at the time of the accident. The 14 CFR Part 91 personal flight was not operating on a flight plan. The pilot and passenger were fatally injured. The flight departed Spearfish, South Dakota, about 1330 mdt. According to the Lawrence County Sheriff's Office, Deadwood, South Dakota, the elevation of the terrain at the accident site was 4,800 and 5,100-feet above mean sea level. The sheriff department's report said the crash occurred in a "...bowl..." created by hilly and mountainous terrain. The report said that "The area is very heavy in vegetation and tree growth." The report continued, "The wreckage was spread out in an area of [a] 100-foot circle. It appeared that the [airplane] came in from the west, striking a pine tree prior to going down." The report details positions of the wreckage and condition. The report is appended to this document. A report from the United States Air Force Civil Air Patrol, Lookout Mountain Comosite Squardron 40063, said, "...the [witness] reported the aircraft flying over lead High School and hearing a loud pop, a sputtering sound and the plane flying Northwest in a 'big swooping circle'... ." The report is appended to this report. Pilot flight records records were not found during the investigation. N4535P's airframe logbook showed it had 2,936.85- hours on it when it received its annual inspection during April 9, 1998. Although burnt to various degrees, all major airframe components were identified. An inspection of the engine revealed that the propeller and spinner remained attached to the engine. One propeller blade was burned off at mid span. The second propeller blade had about 3-inches of its tip broken off. This blade was longitudinally twisted and bent aft about 45-degrees at mid span. The engine and its magnetos, carburetor and vacuum pump were consumed by fire and damaged in a way that prevents operational testing. The engine was disassembled for examination. Other than the internal components being fire damaged and rusted, there was no evidence of a pre-existing mechanical condition that would have prevented development of power. The pilot's toxicological examination was conducted by the Federal Aviation Administration's Civil Aeromedical Institute in Oklahoma City, Oklahoma. The results showed that "...ethanol found in this case is from postmortem ethanol production." The report showed negative results for other drugs. The autopsy was conducted on August 3, 1998, by Dr.Donald M. Habbe, at the Clinical Laboratory of the Black Hills, Rapid City, South Dakota.