On November 15, 1998, approximately 0945 central standard time, a Bell 206B helicopter, N21466, was substantially damaged during takeoff from Matagorda 713, an oil platform on the Gulf of Mexico. The commercial pilot, sole occupant of the helicopter, was not injured. The aircraft was owned and operated by Industrial Helicopters Inc., of Lafayette, Louisiana. Visual meteorological conditions prevailed and no flight plan was filed for the Title 14 CFR Part 91 positioning flight. According to the Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1/2), the pilot stated that his schedule the morning of the accident was to transport several different people to four separate platforms. Before leaving the platform, he untied all three platform tiedowns on the helicopter and visually "checked the floats, skids, cross tubes, and the helicopter in general." After untying the main rotor blade he began to fuel the helicopter. Prior to takeoff, he reported completing the checklist. After takeoff, he proceeded to fly the helicopter to M1638, which was the first scheduled platform. His last stop was M1713 where he dropped off two passengers and proceeded to "shut down" the helicopter. At 9:30 a.m. the 10,771 hour pilot secured, "the two front tie downs" to the platform due to the prevailing 30 to 34 knot wind conditions. Subsequently, the pilot decided to take off and he "checked the wind on the air speed indicator", and the winds were still about the same. He untied the main rotor blade, got into the helicopter, and started the engine. As the pilot "pulled pitch" to takeoff, the aircraft pitched forward. He then pulled back on the cyclic and the aircraft "started to come apart." After the accident, the pilot confirmed that he had not removed the front tie downs on the helicopter. After contacting Industrial Helicopter, Inc., arrangements were made by the company for a medical check and drug test of the pilot. The results were negative. The mast and a section of the tail boom separated from the helicopter during the accident sequence.