On December 21, 1999, at 1130 eastern standard time, a Cessna 172N, N8182E, collided with the ground during an attempted landing at Melbourne International Airport in Melbourne, Florida. The instructional flight was operated by Merritt Island Air Service under the provisions of Title 14 CFR Part 91 with no flight plan filed. Visual weather conditions prevailed at the time of the accident. The airplane sustained substantial damage. The certified flight instructor and the student pilot were not injured. The instructional flight departed Merritt Island, Florida, at 0900. According to the flight instructor, they had completed four touch-and-go landings, and they were attempting a fifth landing when the airplane touched down hard on the runway. The flight instructor also reported no mechanical problems with the airplane. The subsequent examination of the airframe disclosed that the engine firewall and surrounding structure had sustained substantial damage. The airplane examination also failed to disclose a mechanical malfunction or component failure.