On July 26, 2005, at 1400 eastern daylight time, a Flight Design CTSW, N84FS, registered to and operated by a private owner, collided with the ground and nosed over during a landing at Hawkins County Airport in Rogersville, Tennessee. The flight was operated under provisions of Title 14 CFR Part 91 instructional flight. Visual meteorological conditions prevailed at the time of the accident and a flight plan was not filed. The airplane sustained substantial damage. The private pilot received no injuries and the flight instructor received minor injuries. The flight originated from Lonesome Pine Airport in Wise, Virginia on July 26, 2005 at 1330. The flight was on a cross country trip to Rogersville, Tennessee. As the airplane approached Hawkins County Airport, the private pilot prepared for a normal landing on runway 25 with 040-degrees of flaps. According to the flight instructor, as the airplane flared, the private pilot added "a little bit of power to allow for a softer touchdown." The airplane yawed to the right and the flight instructor stated that the private pilot decided to go around and added full power, but the airplane continued to yaw and banked to the right. The flight instructor took control of the airplane, but stated that the flight controls were unresponsive. The flight instructor then elected to land on the grass to the right of the runway. During the landing roll on the grass, the airplane collided with a ditch. The nose gear collapsed and the airplane nosed over. Post-accident examination of the airplane revealed that the airplane was inverted, nose gear collapsed and engine firewall was buckled. The propeller and engine cowling was damaged. The airplane also exhibited damage to the right and left wing, vertical stabilizer, and rudder. Post-accident examination of the flight control surfaces revealed that all flight controls revealed no mechanical failures. Neither pilot reported a mechanical problem with the airplane.