On May 14, 2000, about 1545 eastern daylight time, a Piper J-3, N70546, registered to and operated by a private owner as a Title 14 CFR Part 91 personal flight, made an emergency landing on a beach in Boca Raton, Florida. Visual meteorological conditions prevailed, and no flight plan was filed. The airplane incurred substantial damage, and the commercial-rated pilot and one passenger did not sustain any injuries. The flight originated from Willis Glider Port, in Boynton Beach, Florida, the same day, about 1500. The pilot stated that the aircraft was in level flight at an altitude of 1,300 feet when the engine ceased operating. The pilot further stated that he looked for space to land, but the beach was crowded, except for a small rocky area. During the landing, the left main landing gear assembly hit a rock and separated from the aircraft. The left wing then dropped and hit a sand berm, and the airplane flipped upside down. An FAA inspector who conducted the on-scene examination of the accident aircraft said that fuel was in the aircraft, but it was contaminated with debris when it was transferred to containers, during recovery of the aircraft. Postcrash examination of the aircraft did not reveal any preexisting failure or malfunction. Examination of the engine assembly showed that it rotated normally and continuity of the crankshaft, camshaft, valve train and accessory drives were confirmed. Each cylinder produced finger compression and suction. All oil screens and filters were free of debris. Each magneto operated normally when turned by hand. Examination of the fuel tank, fuel lines, and gascolator revealed no obstructions. The carburetor was disassembled and found to be unobstructed, except for a light filmy residue in the main jet, which was easily dislodged.