On January 6, 2001, approximately 1900 mountain standard time, N108ES, a Cessna 152, owned and operated by the pilot, collided with a frozen lake near Spanish Fork, Utah. The private pilot was seriously injured and his pilot rated passenger received minor injuries. Night instrument meteorological conditions prevailed, and no flight plan had been filed for the personal flight being conducted under Title 14 CFR Part 91. The flight originated at Spanish Fork immediately prior ro the accident. According to the pilot's accident report and a subsequent written statement, he said the pilot-rated passenger was interested in purchasing his airplane and the flight was for demonstration purposes. The two pilots assessed the weather conditions, "We had 5 miles visibility as we could see the lights in town and the moon above," and "we both determined" it was safe to fly "as we had five miles visibility." The pilot wrote that shortly after departure, "At 300 feet [above the runway] we lost visibility. I continued to climb on runway heading" when the pilot rated passenger grabbed the [control] yoke. I asked what he was doing. He said he felt we were turning. I then noticed we were going down. In the ensuing struggle," the airplane collided with frozen Utah Lake, skidded about 300 feet, then fell through the ice near Sandy Beach. The pilot rated passenger told rescuers, "I don't know if we flew into a cloud or what. All of a sudden, we couldn't see the lights on the ground anymore. We were disoriented. [The pilot] thought we should descend a little. That's what we were doing when we hit the lake. We didn't really see it coming." In his written statement the pilot rated passenger said that during the initial climb, "I remember looking out and seeing the lights on the ground. As I recall, we turned left crosswind and I could still see the ground. Shortly thereafter, probably on the downwind leg, I lost sight of the ground. I remember asking him what the airport elevation was and he said about 4,500 feet (4,529 feet). The last altimeter reading I recall was around 5,500 feet. We started to descend to get out of the fog but the situation was very disorienting as neither of us was instrument rated." The passenger assisted the seriously injured pilot out of the airplane. While the pilot clung to the airplane's wing, which remained above the water, the passenger walked across the lake's thin ice, then waded through water towards the rotating beacon at Provo, Utah, Municipal Airport, about 2 miles away. He arrived at the airport about 2030. The pilot was rescued approximately 2300. According to rescuers, the pilot was hypothermic, had fractured both ankles, and had sustained a serious head injury. Provo airport personnel said the visibility was "really low. . .about 2 miles" in fog. Neither pilot was instrument rated.