On June 11, 2005, at an estimated 1430 Pacific daylight time, an Avia Stroitel AC-4B glider, N1198Z, was destroyed when it impacted terrain near Wenatchee, Washington. The student pilot, the sole occupant in the aircraft, was fatally injured. Cascade Soaring Society, Inc., was operating the glider under 14 CFR Part 91. Visual meteorological conditions prevailed for the local solo instructional flight. The flight originated from Wenatchee, Washington, approximately 60 minutes before the accident. No flight plan was filed. The pilot's flight instructor said that the student pilot had approximately 12 hours of flight experience over 18 training flights; he said that this was the student pilot's first flight in this make and model of aircraft. The student pilot was scheduled to fly a one hour flight. When he did not return, a search airplane departed and found the glider on the back side of a mountain ridge approximately 3 nautical miles from the airport. The tow-pilot that towed the glider airborne said that on the ground, the wind was variable from 240 degrees to 280 degrees at 11 to 13 knots. He further stated that the student "did a great job [on departure], he was in position all the time." The tow-pilot said that when he passed through 4,250 feet, the student released from the tow rope. He said that the "ridge lift" just northeast of the airport was "very good." Another glider pilot, flying in the same area, reported that the winds at 6,000 to 7,000 feet were out of the west at 6 to 7 knots. The Douglas County Corner, from Wenatchee, Washington, ordered an autopsy to be done on the student pilot, which was completed on June 13, 2005. The Forensic Pathologist that performed the autopsy determined that the cause of death was multiple internal injuries due to blunt impact forces. The Federal Aviation Administration's Civil Aeromedical Institute (CAMI) in Oklahoma City, Oklahoma, performed toxicology test on the student pilot. According to CAMI's report (#200500130001), the blood samples that were tested for carbon monoxide, cyanide, volatiles (ethanol), and drugs found negative results.