On December 18, 1997, at 1215 central standard time, a Cessna 172F, N8426U, impacted terrain following a loss of control during a go-around maneuver at the Louisiana Regional Airport, Gonzales, Louisiana. The airplane, owned and operated by a private individual under Title 14 CFR Part 91, sustained substantial damage. The student pilot and the airline transport rated pilot/flight instructor received serious injuries. Visual meteorological conditions prevailed for the local instructional flight and a flight plan was not filed. During telephone conversations, conducted by the investigator-in-charge (IIC), the witness (pilot and mechanic) and the airport manager reported that the flight instructor had retired from the military and started flight instructing in civilian aircraft in 1997. Following a series of touch and go's, the airplane bounced hard during a landing. During the go-around maneuver, with flaps extended, the nose pitched high (15 to 20 degrees), the airplane yawed to the left, and then the airplane entered a stall/spin. The left wing struck the ground, the airplane bounced, and the right wing struck the ground, before the airplane came to rest upright on the landing gear. The engine was developing power during the go around. The witness and local authorities responded to the scene and called 911. The FAA inspector and the airframe representative examined the aircraft. Structural damage occurred to the elevators, wings, engine, and firewall. Flight control continuity was confirmed. The flaps were found extended to 10 degrees. Portions of the left wing were found in a ground scar 25 feet in length. The airplane came to rest 54 feet from the initial impact point. During telephone interviews, conducted by the IIC, and on the Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1/2), the flight instructor reported that the accident occurred during the 4th touch and go. On short final, the "nose of the aircraft rotated downward at an altitude of approx[imately] 20-30 feet above [the] runway." The instructor gave a verbal command to "pull up - pull up." However, the main wheels, followed by the nose wheel struck the runway and the aircraft bounced as the flight instructor took control of the aircraft, applied full power, and retracted the flaps. The aircraft veered uncontrollably to the left and impacted the ground.