On December 5, 1999, at 0745 central standard time, a Bell 206L-1 helicopter, N600CK, registered to Evergreen Equity, Inc., of McMinnville, Oregon, and operated by Evergreen Helicopters International of Galveston, Texas, sank after landing on the water, following a loss of engine power near Ship Shoal 225, which is located in the Gulf of Mexico. The airline transport pilot, sole occupant of the helicopter, sustained serious injuries. Visual meteorological conditions prevailed, and a company flight plan was filed for the 14 Code of Federal Regulations Part 135 nonscheduled flight. The flight originated from platform 89 located in the Ship Shoal 225 area, at 0740, and was destined for a platform in the Ship Shoal 222 area. The operator reported that when the helicopter was about halfway to its intended destination, approximately 150 feet above the water, the engine lost power. The pilot initiated an autorotation to the water and deployed the floats. The helicopter landed "hard," but remained upright and afloat. The pilot got the emergency raft from the cabin and inflated it. After getting into the raft, the waves, which were estimated at 6-8 feet, overturned the helicopter, and it sank in 160 feet of water. The helicopter was not recovered, therefore, the reason for the loss of power could not be determined. Several weeks after the accident, a fisherman recovered in his net, the portion of the tail boom aft of the horizontal stabilizer.