On September 23, 1996, at 2245 central daylight time, a Hughes 269C, N7492F, owned and operated by the City of Houston, sustained substantial damage during an autorotation near Houston, Texas. The flight instructor and commercial pilot receiving instruction received minor injuries. Visual meteorological conditions prevailed for the Title 14 CFR Part 91 night instructional flight, and a flight plan was not filed. The flight originated at the Houston Hobby Airport, Houston, Texas, about 2110. The flight instructor reported that he was demonstrating an autorotation from 50 feet AGL. He initiated the autorotation to the grassy area between taxiway Foxtrot and taxiway Golf 2, just west of runway 17. The helicopter touched down with skids level and he increased the collective to keep the aircraft skids light on the ground and to maintain a straight ground track. The helicopter had traveled approximately 70 feet, and was moving at approximately 20 knots when the aircraft pitched forward and to the right. He "felt at least three severe impacts to the aircraft and then the aircraft was stopped." Examination of the helicopter by the FAA inspector and operator revealed that the left and right skid tubes were fractured, and the right skid was detached from its front and rear gear dampers. The tailboom and tail rotor were "sheared off' by the "main rotor blades." According to the FAA inspector, a "certified A&P [mechanic] failed to follow inspection procedures as outlined in [the] work card and [the] Manufacturer Maintenance Manual." According to the operator, the bottom of the right skid tube was "worn beyond the manufacturers tolerances."