HISTORY OF FLIGHT On April 17, 2004, at 1930 mountain daylight time, a Cessna 150H, N105DP, piloted by a private pilot, was substantially damaged during a forced landing into a lake, 1/2 mile east of the Boulder Municipal Airport (1V5), Boulder, Colorado. Visual meteorological conditions prevailed at the time of the accident. The personal flight was being conducted under the provisions of Title 14 CFR Part 91 without a flight plan. The pilot reported minor injuries. The local flight originated at approximately 1915. The pilot said that he had just completed his third touch-and-go landing. He was approximately 300 feet in the air when his engine began to run rough. The pilot said he "put a little mixture in [and] the engine started to run fine for about 5 seconds. Then the engine died." The pilot said the only place he could land was the lake. He said that as he touched down, the airplane "skimmed for a few seconds and then it went over on its back." The pilot said he got out through the windscreen, got on top of the bottom of the wing, and then swam to shore. He said the airplane sank nose first about 30 seconds later. PERSONNEL INFORMATION The pilot, age 17, held a private pilot certificate with airplane single-engine land rating. The certificate was dated September 7, 2003. The pilot had a third class medical, dated July 23, 2002. The medical certificate cited no limitations. The pilot reported having 350 total flying hours, 180 in single-engine land airplanes, and 8 hours in the accident airplane. AIRCRAFT INFORMATION The airplane, serial number 150-68960 was a 1968 Cessna 150H. The airplane was used for pilot training and personal pleasure flying. According to the airframe logbook, the airplane underwent an annual inspection on November 1, 2003. At the time of the inspection the airplane logbook showed a recorded tachometer time of 9,988.72 total hours. A previous entry on March 3, 2003, reflecting an engine oil change showed a tachometer time of 9,200.16 hours. The tachometer time recorded at the accident site was 9,394.74 hours. WRECKAGE AND IMPACT INFORMATION The accident site was located at the center of a pond located approximately 3,000 feet east of the departure end of 1V5 runway 8R. The airplane was predominately intact and rested upright on its landing gear submerged in approximately 15 feet of water. The airplane's right wing leading edge, from mid span outboard to the wing tip, was crushed aft to the forward spar. The left wing forward spar was bent downward. The airplane's forward windscreen was broken out and fragmented. The remainder of the airplane was undamaged. On April 19, 2004, the airplane was retrieved from the bottom of the pond. Flight control continuity was confirmed. The airplane was retained for further testing. TESTS AND RESEARCH The airplane's engine was examined at Greeley, Colorado, on May 7, 2004. The examination showed that the left magneto was not functional. No other anomalies were found. Later, an internal examination of the magneto showed corrosion around the points, the P-lead, and the capacitor. ADDITIONAL INFORMATION A party to the investigation was the FAA Flight Standards District Office, Denver, Colorado. The airplane wreckage was released to the owner's insurance company.