On June 29, 2000, at 2015 hours Pacific daylight time, a Piper PA-32-260, N933AC, was destroyed during a forced landing into Lake Almanor, after the engine lost power during takeoff initial climb from Rogers Field, Chester, California. The instructional flight was operated by Aero Flite, Inc., under 14 CFR Part 91. The commercial pilot and the student pilot received minor injuries. The flight was destined for the Reno/Stead Airport, Reno, Nevada. Visual meteorological conditions prevailed and no flight plan was filed. The pilot told the Safety Board investigator that the flight on which the accident occurred was his fourth flight of the day in the aircraft. He started the day in Stockton, California, with the fuel tanks of the aircraft full. He flew to Chester, then to Reno (Stead), and back to Chester. The total was about 2 hours 30 minutes, and the airplane was not serviced after departing Stockton. According to the pilot, full tanks is sufficient for about 5 hours flying. The airplane and engine flew fine and there was no indication of any developing problems with the engine. The accident occurred on the next takeoff from Chester. The pilot said the takeoff on runway 16 was routine, the engine was smooth and powerful, and all the instruments were in their normal operating ranges. The fuel selector was on the right tank and there was about 17 gallons fuel in that tank. When about 150 feet agl, he reduced the propeller rpm and at that time the engine started "cutting out." It never totally quit. He verified that the fuel boost pump was on, and recalled that the fuel pressure gauge and oil pressure gauge were in the green arc. He changed fuel tanks but had no more time to restart the engine before ditching in the lake. The second pilot's report to the Safety Board differed from the first pilot's in that the second pilot reported their intent was to remain in the pattern at Chester, initially, and perform some touch-and-go landings before proceeding to Reno. The second pilot also reported that he believed the engine "picked up" again just before they ditched in the lake. The aircraft was examined by the Safety Board at the facilities of Plain Parts, Pleasant Grove, California, on July 11, 2000. According to the recovery company operator, the wings and empennage were separated from the fuselage when it was removed from the lake and the engine remained attached to the fuselage by control cables and hoses. The engine carburetor was broken at its base from the engine sump and the carburetor was not recovered. One blade of the propeller was undamaged and the other was twisted 180 degrees and bent aft about 80 degrees along its span. The airplane was equipped with four fuel tanks, each individually selectable from the tank selector valve in the cockpit. In the cockpit, the fuel selector was in the left tip fuel tank position. The fuel boost pump switch was "on"; the primer was in the forward and locked position; the magneto switch was in the "both" position; and the alternator and master switches were "on." The throttle was forward, the propeller control was damaged, and the mixture control was extended (out) about 1 inch from the full forward position. The outboard portion of the right and left wings both exhibited substantial leading edge damage and the tip fuel tanks were ruptured. The inboard (main) fuel tanks were intact, although the right-hand tank had a dent of about 2 inches in the leading edge. The fuel vent/overflow lines were unobstructed and the fuel cap vents were also open. The fuel selector valve linkage was intact to the selector valve. The valve was in the position that fed fuel from the left tip tank to the engine. The fuel sump contained two dissimilar liquids resembling water and aviation fuel. When electric power was applied to the fuel boost pumps the pumps audibly operated and pumped about 1/8-cup of liquid resembling aviation fuel. The engine driven (mechanical) fuel pump remained attached to the accessory case and the reciprocating drive rod in the accessory case operated when the engine was rotated. The hose fittings at the inlet and outlet were sheared off and the outlet hose to the carburetor was absent. The check valves inside the pump were obstructed by mud and the diaphragm was intact. When rotated by hand the engine exhibited mechanical continuity with thumb compression, valve function, and rotation of the accessory case gears. The magneto impulse coupling, installed on the left magneto only, released approximately at top dead center. The accessory case gearing was intact and the crankshaft gear drive pin was intact. The induction tubes were tight and intact. The oil pump rotated freely and smoothly by hand. The oil pump suction screen was clear, as was the paper element type filter. The cylinder walls exhibited a uniform, shiny, unscored appearance below the piston head; however, the combustion chambers exhibited a corroded (rusted) appearance. The piston rings were free in the piston grooves and unbroken. The camshaft and crankshaft bearing surfaces were shiny and unscored and the cam lobes were visually uniform and not excessively worn. The propeller governor drive was intact. The magnetos rotated freely with appropriate resistance due to magnetic impedance. The magnetos were still moist internally and did not spark when rotated by hand. The magneto p-leads from the magneto switch were severed, however, with the switch in the "both" position, both p-leads were ungrounded. The spark plug wires were severed, however, the terminations at the spark plugs and the magnetos were intact and tight. The spark plug electrodes exhibited a rusted appearance with modest oval wear to the center electrode and a gap of about 0.018 inches. The foam-type air filter element was intact. The muffler exhibited impact damage to the forward face, however, the flame tubes were intact and the outlet was unobstructed. The inside surfaces of the exhaust pipes exhibited a uniform gray appearance.