On May 9, 1996, about 1230 eastern standard time, a Piper PA-28R-201, N9816C, registered to Aretz Flying Service, Inc., was substantially damaged during a gear up landing in Lafayette, Indiana. The commercial rated flight instructor and the commercial rated pilot on board the airplane reported no injuries. The local, 14 CFR Part 91, instructional flight originated about one hour prior to the accident. Visual meteorological conditions prevailed and no flight plan was filed. The flight instructor reported that she was sitting in the left seat observing the student, who was also a commercial rated pilot, flying from the right seat. The instructor reported that the student put the flaps down to 10 degrees on downwind and she was "surprised." He then put the gear down. She asked him why he had lowered the flaps prior to the gear. He responded that he had been taught to wait until descent to lower the gear. Turning final, she checked the flap handle, checked the gear lights, and noticed that the red warning light was off. She reported that she heard the gear warning horn during the landing flare and the next thing she remembered was "stopping and staring at the bent prop." During an interview with a Federal Aviation Administration (FAA) Inspector, the student reported that he had performed a "mental GUMPS check" and was "distracted." Examination of the airplane revealed no evidence of preimpact malfunction.