On March 23, 2004, about 1918:34 central standard time, an Era Aviation Sikorsky S-76A helicopter, N579EH, crashed into the Gulf of Mexico about 70 nautical miles south-southeast of Scholes International Airport (GLS), Galveston, Texas. The helicopter was en route to the drilling ship Discoverer Spirit. The captain, copilot, and eight passengers aboard the helicopter were killed, and the helicopter was destroyed by impact forces. The flight was operating under the provisions of 14 Code of Federal Regulations Part 135 on a visual flight rules flight plan. Night visual meteorological conditions prevailed at the time of the accident.The National Transportation Safety Board determines that the probable cause of this accident was the flight crew's failure to identify and arrest the helicopter's descent for undetermined reasons, which resulted in controlled flight into terrain.