On December 15, 2007, approximately 1458 central standard time, a single-engine Bell 407 helicopter, N407AK, registered to and operated by Rotorcraft Leasing Company LLC, lost tail rotor control while in cruise flight over the Gulf of Mexico approximately 98-nautical miles off the coast of Texas. The commercial pilot successfully autorotated the helicopter to the ocean. The pilot and his passenger were able to enter a life raft and were not injured. A visual flight rules flight plan was filed and visual meteorological conditions prevailed for the 14 Code of Federal Regulations Part 135 on-demand air taxi flight. The flight originated at 1453 from offshore platform High Island A573A, and was bound for offshore platform High Island A376, in the Gulf of Mexico. On a NTSB Form 6120, the 2,075-hour pilot stated that during cruise flight, he experienced a violent vibration in the airframe. Within a few seconds a noise similar to a loud "pop" was heard and the helicopter began to yaw to the right. The pilot attempted to correct the adverse yaw but could not regain control of the helicopter. Rather than continue flight or attempt a platform landing with a loss of tail rotor effectiveness, the pilot elected to perform an autorotation in the Gulf of Mexico. A distress message was transmitted and the emergency floatation system was activated prior to landing. Once successfully landed, the pilot radioed a position report and shutdown the helicopter. The life raft was deployed and both pilot and passenger successfully egressed the helicopter. While waiting for the US Coast Guard, the pilot visually inspected the helicopter and could observe no damage or malfunction. A Coast Guard helicopter crew recovered both personnel. The helicopter was capsized due to swells in excess of 15 feet, sank and was not recovered. At 1452 weather reported at Scholes International Airport, Galveston, Texas, approximately 105 nm northeast was winds from 320 degrees at 21 knots gusting to 27 knots, temperature 63 degrees Fahrenheit, and a barometric pressure of 29.98 inches of Mercury.