On September 22, 2005, about 1400 eastern daylight time, a Eurocopter Deutschland BK-117-B2 helicopter, N117MK, was substantially damaged during a hard landing at Ohio State University Airport (OSU), Columbus, Ohio. The certificated airline transport pilot and four passengers were not injured. Visual meteorological conditions prevailed and no flight plan had been filed for the local business flight conducted under 14 CFR Part 91. The pilot reported he had flown around the Columbus area on a public relations flight, and was returning to OSU. He noticed another helicopter running up on the ramp, and elected to alter his approach with the intent of landing southwest of the ramp, to avoid any "rotor wash." The pilot flew parallel to runways 27 left and right, leveled off at 50 feet, and began a right turn to approach the ramp from the west. The pilot added that he observed a kneeboard fall from the co-pilot's side of the helicopter, and land near the cyclic control boot. He tried to straighten the helicopter; however, the cyclic control felt "stiff," and could only be moved slightly to the left or aft. The helicopter continued to descend, and landed hard. On the NTSB pilot/operator accident report form, the pilot also indicated that the helicopter may have experienced a control malfunction or hydraulic failure. A helicopter pilot, who witnessed the accident, stated that the helicopter's approach was fast, steep, and conducted with a tailwind. The helicopter started to flare about 100 feet above the ground, and entered a "hard right turn" just prior to the main rotor blades and the right skid contacting the ground. Examination of the helicopter, and its associated hydraulic control system by Federal Aviation Administration inspectors did not reveal any pre-impact malfunctions. In addition, attempts to restrict the cyclic control movement by positioning the kneeboard at various locations around the cyclic control could not be duplicated. The helicopter was maintained under an approved inspection program, and had been operated for about 30 hours, since its most recent inspection. The pilot reported 3,400 hours of total rotorcraft flight experience, which included about 2,300 hours in the same make and model as the accident helicopter. Winds reported at OSU, at 1353, were from 190 degrees at 12 knots. The pilot reported that at the time of the accident, the wind sock was "limp."