On June 27, 1999, about 1500 hours Hawaiian standard time, a Schweizer SGS-2-33A glider, N17902, sustained substantial damage during a hard landing at Dillingham Field in Wailua, Hawaii. The glider was being operated by Honolulu Soaring Club under the provisions of 14 CFR Part 91 as an instructional flight. The student pilot, who suffered minor injuries, departed Dillingham about 1415 on a local unsupervised solo flight. Visual meteorological conditions prevailed and no flight plan was filed. The pilot stated the winds were blustery at 15 to 20 knots. He turned to final approach for runway 8 at 350 feet with full spoilers. At 200 feet he reduced spoilers to 25 percent. He was maintaining 75 to 80 miles per hour and increased spoilers to 50 percent at 100 feet. He stated he experienced a sudden loss of velocity at 25 feet, followed by a nose down attitude. After the glider contacted the runway, the nose went up and the glider became airborne. The pilot applied full spoilers with a forward slide in an attempt to flare. The nose touched down followed immediately by the tail contacting the ground. The glider became airborne again, then touched down and stopped within 15 to 20 feet. The landing gear mounting frame was crushed and a tube fractured in the fuselage frame.