On June 22, 1997, at 1327 central daylight time (CDT), a Cessna 172RG, N6280R, operated by the Lewis University Aviation Department, sustained substantial damage when the landing gear collapsed during landing. The pilot and passenger were not injured. The 14 CFR Part 91 flight had departed the Lewis University Airport, Romeoville, Illinois, at 1230 CDT en route to Meigs Airport, Chicago, Illinois. Visual meteorological conditions prevailed and no flight plan was filed. The pilot reported that while he was on the downwind leg for runway 18, he completed the landing checklist. He checked that the landing gear was locked and the green light was on while he was on the base leg. He reported that, "As I flared to land, I hit the belly of the plane on the runway." He reported that, "By then I realized that the aircraft's landing gear had collapsed, and slid down the runway." He evacuated the airplane when it came to a stop. An Airworthiness Inspector from the Federal Aviation Administration inspected the airplane. He reported damage to the right side of the belly area, particularly on the lower wing strut attach bulkhead and the forward landing gear box bulkhead. The belly skin and associated attaching hardware was ground off approximately three inches on either side of the bulkheads. Several antennas were damaged from being dragged along the ground. The flat antenna located on the left side of the belly was ground at an angle, indicating the right side of the aircraft was lower. The inspector reported that, "Its damage indicated all three landing gear would have to be in a retracted position. Any single gear extended would not have allowed the damage to the unit." The inspector reported that, "The damage on the belly appeared to be the result of landing with the gear in the retracted position." The landing gear was inspected for damaged. The aircraft was put on jack stands. The landing gear was cycled numerous times both up and down with no anomalies indicated. There were no scratch marks on the landing gear, nor any damage to the landing gear gearbox. Both tires exhibited scuff marks about four inches wide perpendicular to the tire tread, but no rotational scuffing of the tires.