On September 6, 1997, at 1419 eastern daylight time, a homebuilt Marske-Monarch 1997, an experimental glider, N5377, was substantially damaged when it collided with terrain while maneuvering to land at the Braxton County Airport, Sutton, West Virginia. The certificated private pilot was seriously injured. Visual meteorological conditions prevailed and a flight plan was not filed. The local, personal flight was conducted under 14 CFR Part 91. According to the pilot, the glider was towed to 500 feet AGL, and released. He said when he started his turn, the left wing dropped, and the airplane entered a spin to the left. He applied opposite rudder, and the airplane recovered after two turns. He said he was disoriented shortly thereafter, and does not recall anything else. A witness, an instructor, reported that the glider made two 360 degree turns in normal flight. He said that about 400 feet AGL, the glider entered a spin, rotated about 2 turns and recovered. He said that the glider entered a second spin, about 100 feet AGL, and struck the ground at the approach end of runway 01. According to a Federal Aviation Administration (FAA) Inspector, the glider was undergoing 10 hours of flight testing. The glider was certified 3 days prior to the flight, and was test flown six times on the day of the accident. He said the glider came to rest about 180 feet beyond the approach end of runway 01. The glider was examined at the accident site by the FAA Inspector. The Inspector stated that flight control continuity was confirmed. He also reported that there was no record that the glider's pitot static system was calibrated prior to this flight, as recommended in advisory circular AC-90-89. The pilot reported over 10 of flight experience in gliders, including 1 hour in make and model. He reported that there was no mechanical malfunction with the glider.