On January 12, 1996, at 0930 central standard time, a Schweizer 269C, N3623T, sustained substantial damage during a forced landing near San Ygnacio, Texas. The commercial helicopter pilot and his passenger were not injured. The aircraft was registered to and operated by Smith Helicopters under Title 14 CFR Part 91. The flight originated from a private airstrip near San Ygnacio, Texas, at 0900. Visual meteorological conditions prevailed for the local flight and no flight plan was filed. The pilot reported that he heard a loud "bang" while hovering sideways at approximately 12 MPH at 70 feet out of ground effect. He responded by applying the right anti torque pedal to straighten the helicopter, however the helicopter did not respond to pedal inputs. According to the pilot, the engine produced high RPM, but the tail rotor and main rotor RPM decreased. The pilot initiated an autorotation. The pilot further reported that, during touchdown with lateral movement, the helicopter rolled over coming to rest on its right side. The tail boom, the engine mount, and the skids sustained substantial damage, and the tail rotor separated from the helicopter. Inspection of the aircraft revealed that the swedged ball on the end of the clutch control cable had separated, which allowed the rotor drive system's clutch assembly to disengage.