On April 11, 1997, about 1500 Alaska daylight time, a tundra tire equipped Piper PA-18-150 airplane, N8071D, was destroyed by impact forces and a postimpact fire, when it collided with terrain about nine miles south of Manokotak, Alaska. The private pilot and the one passenger aboard were fatally injured. The local flight operated in visual meteorological conditions without a flight plan. The flight last departed Dillingham, Alaska, time unknown. According to a witness who was riding a snow machine in close proximity to the accident site, the airplane was observed flying very low to the ground, possibly below the top of the banks of the Igushik River. The witness last saw the airplane climb quickly, slow down, and begin a left turn. He lost sight of the airplane, but seconds later heard a loud noise and saw smoke near where he last saw the airplane. He rode his snow machine to the accident site, but was unable to approach the airplane due to an intense fire. An FAA inspector from the Anchorage Flight Standards District Office went to the accident site on April 12. Upon arrival, he said he saw the airplane crashed nose down on nearly level, frozen tundra. He wrote in his report that the airplane "...appeared to stalled and spun into the tundra." He noted the propeller was torn free from the engine, and came to rest about 20 feet from the airplane. He said the engine appeared to have power upon impact due to the torsional load signatures on the propeller. Engine and flight controls were checked for continuity and found to be functional. No evidence of any preimpact mechanical malfunction was discovered. No aircraft log books were available for examination, and the pilot's personal logbooks were not located. On February 25, 1997, the pilot completed a Second Class application for an FAA Airman's Medical Certificate. At that time, the pilot indicated he had 156 total flight hours, with 106 of those hours obtained within the preceding six months. On April 14, an autopsy was performed by the State of Alaska's Medical Examiner, 5700 East Tudor Road, Anchorage, Alaska. The examination disclosed the pilot died of massive blunt trauma. No evidence of any substantive preexisting disease was discovered. Toxicological samples taken from the pilot were submitted to the FAA's Civil Aero Medical Institute for examination. Urine and kidney fluid proved positive for Marihuana derivatives. A review of the toxicological results by the staff NTSB physician revealed that it could not be determined what, if any, effect the Marijuana may have had on the pilot's performance, nor when it was last consumed.