On November 30, 2014, about 1740 central standard time, a Piper PA-28R-201T, N533MC, was damaged during a hard landing at the Addison Airport, near Dallas, Texas. The pilot and his three passengers were not injured. The airplane incurred damage to the wings and fuselage. The aircraft was registered to Metroplex Flight Services, LLC. and operated by the pilot under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed for the flight, which was not on a flight plan. The flight originated from the Eppley Airfield, Omaha, Nebraska about 1700.The pilot reported that during landing, a gust of wind encountered just prior to touchdown pushed the airplane sideways into the grass adjacent to the 100- foot wide runway. The airplane subsequently landed hard and received substantial damage to the wing and fuselage. The weather conditions reported at the accident airport included wind from 50 degrees left of runway heading at 9 knots gusting to 19 knots. The pilot reported no abnormalities with regard to the flight control system of the airplane. The pilot reported that during the cruise portion of the flight, smoke was entering the cockpit from behind the instrument panel. He reported that he opened the vent window and the smoke cleared and that there was no obstruction to vision during the landing. Examination of the airplane after the accident revealed that three of the four screws attaching the valve cover on the right rear cylinder were missing. Evidence of oil leaking from the valve cover onto the exhaust was evident.