On July 1, 1998, at 1100 central daylight time, a Piper PA22, N5181Z, sustained substantial damage during impact with the terrain approximately 5 miles south of Spearfish Airport, Spearfish, South Dakota. The pilot received fatal injuries. The passenger reported minor injuries. The airplane was being operated as a personal flight under provisions of 14 CFR Part 91 when the accident occurred.. Visual meteorological conditions prevailed at the time and no flight plan was on file. The flight originated in Spearfish, South Dakota, about 1030, and was en route to Cheyenne, Wyoming The passenger was a non-pilot and said that he remembered the airplane being buffeted around and descending into the trees. The pilot survived the accident and succumbed later in the hospital. Emergency responders and FAA inspectors were on site within two hours of the accident and said that there was no smell of fuel nor did they find any fuel leaking from the wreckage. The left fuel tank was intact and contained only unusable fuel. The fuel selector was found selected to the left fuel tank. An inspection of the airplane subsequent to the accident failed to reveal any mechanical anomalies other than those associated with ground impact. The carburetor had some fuel in it and no water was found. Magnetos produced sparks on all plugs. A compression check was performed on cylinders and all had thumb compression. The left fuel was filled with water and a small leak was noted by the drain plug which was associated with impact damage.