On July 5, 1997, at 1200 eastern daylight time, a Piper PA-34-200, N56676, received substantial damage during a hard landing on runway 26 (3,501' x 75' dry/asphalt) on Mackinac Island, Michigan. The private pilot told police he encountered windshear during the landing. The pilot and four passengers reported no injuries. The personal 14 CFR Part 91 flight was operating in visual meteorological conditions. No flight plan was on file. The flight departed Jenison, Michigan, at 1030. The pilot said that the airplane encountered a "few bumps" on final approach. He said that he found the airplane was high over the runway; that he held the nose up and allowed the airspeed to decrease. He said that the airplane bounced once and then came down with a loud bang. An examination of the airplane subsequent to the accident failed to reveal any preexisting anomalies.