On June 11, 1996, at 1850 hours Pacific daylight time, a Cessna 150F, N7880F, collided with trees in mountainous terrain 7 miles northeast of Placerville, California. The aircraft was destroyed and the unlicensed pilot and one passenger were seriously injured. Visual meteorological conditions prevailed for the local personal flight. According to witnesses, the aircraft flew into rising terrain, passing low over a residence, before impacting a 60-foot-tall tree about 40 feet above the base. The impact severed the left wing of the aircraft outboard of the fuel tank. The remainder of the aircraft wreckage then came to rest upslope about 50 feet west of the tree. There was a postcrash fire in vicinity of the left fuel tank and the engine, which did not spread, and was extinguished by fire department personnel. One and one-third gallons of fuel were found in the right-hand fuel tank. One blade of the propeller was undamaged and the other was bent aft about 30 degrees with no torsional twisting or chordwise scratches. Paramedics who responded to the scene told the NTSB investigator that the two occupants were combative and smelled of alcohol. A blood alcohol level of 0.237 percent was measured in a blood sample collected from the pilot on admission to the hospital at 2030. Other witnesses contacted the FAA's Sacramento, California, Flight Standards District Office the morning following the accident and reported the aircraft was seen flying low over water skiers on a nearby lake 1 hour before the accident. The witnesses, who were able to provide the registration number of the aircraft, reported the aircraft passed within about 10 feet of one water skier. The pilot refused to complete the accident report on the advice of his attorney. The owner of the aircraft completed the aircraft portion of his report. During a telephone call, the owner said that the pilot was his mechanic and was not authorized to fly the aircraft. The pilot/mechanic recently completed maintenance on the aircraft and the owner said he was unsure if the maintenance had been signed off in the aircraft logbooks and the aircraft approved for return to service. Information in this report on the pilot and aircraft were derived from FAA records and information obtained from the report of the Cessna Aircraft Company investigator who was a party to the investigation.