On July 10, 2001, approximately 1745 central daylight time, a Sikorsky SK-76A helicopter, N164AG, registered to and operated by Air Logistics L.L.C., of New Iberia, Louisiana, was substantially damaged during a loss of control while maneuvering in the vicinity of Sabine Pass, Louisiana. The airline transport rated pilot, who was the sole occupant of the helicopter, was not injured. Visual meteorological conditions prevailed and a company flight plan was filed for the 14 Code of Federal Regulations Part 91 positioning flight. The flight originated from the company's base located at Intracoastal City, Louisiana, at 1700. The pilot stated that during run up at Intracoastal, the aircraft "seemed to have a bit of a ground track problem." He then proceeded to his destination (Sabine Pass) and noticed that the in-flight ride was a "little rougher" than most S76's that he had flown. About ten miles from Sabine, he decided to initiate an auto rotation RPM check. After disengaging the autopilot, he lowered the collective and retarded the throttles to idle. Subsequently, the nose "pitched up and snapped to the left to a vertical descent." After the pilot advanced the throttles, the aircraft began to shake "violently." Subsequently, he recovered "full control." After landing at Sabine, a post flight inspection revealed damage to the main rotor blades and hub. Further inspection of the hub and blades revealed that all 4 main rotor blades had cracks about 1 foot outboard of the blade root seals. All four spindle assemblies and flap restrainers were also damaged. No impact damage was observed on either the hub or blades.