On May 30, 1996, about 1420 eastern daylight time, a Schweizer SGS233A glider, N1197S, was substantially damaged following a collision with trees during a landing approach at the North Raleigh airport, Franklinton, North Carolina. Neither the instructor pilot nor the student pilot were injured in the accident. The glider was being operated under the provisions of Title 14 CFR Part 91 by the pilot. Visual meteorological conditions prevailed at the time, and no flight plan had been filed for the instructional flight. The flight originated at the Franklinton airport approximately 1400 eastern daylight time. The instructor pilot stated the student pilot was operating the aircraft controls during the landing approach. The glider started to drift right of the runway centerline. As the glider drifted farther, the instructor took over the flight controls. He reported having full deflection of the flight controls to counteract the drift, but the glider continued to drift. The right wing tip of the glider then hit trees, and the glider spun until it came to rest in the trees approximately ten feet off the ground. The instructor pilot reports that the trees are about 25 feet from the edge of the runway.