On August 26, 1999, at 1155 central daylight time, a Bell 206-L3 helicopter, N6610E, was substantially damaged when it impacted the lower deck of an oil platform while attempting to takeoff from Main Pass 225A, an offshore platform located in the Gulf of Mexico. The airline transport rated pilot sustained minor injuries and his one passenger sustained serious injuries. The helicopter was registered to and operated by Petroleum Helicopters, Inc., of Lafayette, Louisiana. Visual meteorological conditions prevailed for the 14 Code of Federal Regulations Part 135 on-demand air taxi flight, and a company VFR flight plan was filed. The flight was originating at the time of the accident. According to the pilot, the helicopter was facing downwind as he was preparing to takeoff. He rolled the throttle on, and at "about full power," the helicopter began "sliding across the platform." He rolled the throttle off and the helicopter "stopped for a few seconds, [and] then started sliding again." As the helicopter approached the edge of the helipad, the pilot rolled on full throttle again. According to the pilot, "by this time [he] had the aircraft turned left almost straight into the wind." Part of the skid landing gear was resting on the horizontal safety fence surrounding the helideck. When the pilot applied collective to takeoff, the helicopter began bouncing on the edge of the helipad, yawed to the right, and "slid over the edge to the deck below." The helicopter came to rest on the lower deck in a near vertical attitude. The pilot reported that the wind was from the east-southeast at 25 knots, and a weather cell was developing 5 to 7 miles to the east-southeast of the platform. Examination of the helicopter, by an FAA inspector, revealed that the tailboom, including the tail rotor drive shaft, was severed. The tail rotor drive shaft "showed evidence of rotation." Both main rotor blades were severed 6 feet outboard from the main rotor hub. Flight control continuity was established to the cyclic, collective, and tail rotor systems.