On August 31, 2008, at approximately 1418 central daylight time, a Schleicher. ASW-20B glider, N30WK, was substantially damaged upon impact with terrain near Cleburne, Texas. The commercial pilot, the sole occupant, was fatally injured. The glider was owned and operated by a private individual. Visual meteorological conditions prevailed and no flight plan was filed for the 14 Code of Federal Regulations Part 91 personal flight. The flight originated from TSA Gliderport (TA11), Midlothian, Texas as a local flight at approximately 1326. A local resident contacted emergency services to inform them that a glider had crashed. An inspector from the Federal Aviation Administration (FAA) also responded and documented the crash site. The glider impacted an open field near a residence. The flaps were set to "2" corresponding with -6 degrees of flaps (flaps up 6 degrees). The wreckage was recovered to a secure location for examination. An examination was conducted by the NTSB Investigator-in-Charge. Flight control continuity was established to the rudder, elevator, and ailerons. Continuity to the airbrakes and flaps was also established. No pre-impact anomalies were discovered with the airframe. The accident flight was recorded by an Cambridge Aero Instruments data recording device. An examination of the data revealed that the glider was towed from TA11 and began a flight to the southwest of the airport. The device recorded several successful attempts to thermal the glider. At approximately 1355 the glider began maneuvering to obtain thermal lift, but continued to descend. The flight continued over a field and the glider appeared to enter a normal left traffic pattern. The last recorded point was at 1417 with the glider at 895 feet mean sea level (about 150 feet above ground level), traveling 29 miles per hour, in a descent of approximately 390 feet per minute on "final approach" leg. The glider pilot had logged over 5,279 hours in various military and civilian aircraft. The pilot had logged approximately 399 hours in gliders with at least 7.5 hours in the accident glider. An autopsy was performed on the pilot by the Tarrant County Medical Examiner's Office, Fort Worth, Texas. The medical examiner ruled the manner of death as a result of multiple blunt force trauma. Forensic toxicology was performed on specimens from the pilot by the FAA Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma. The toxicology report stated the presence of carbon monoxide, cyanide, was ethanol was not detected. The report notes: DIPHENHYDRAMINE detected in Blood DIPHENHYDRAMINE detected in Liver IBUPROFEN detected in Blood According to the Chief of the FAA Forensic Toxicology Research Team, diphenhydramine was not quantified in the pilot's blood because the level was below the laboratory's calibration curve. At 1425, an automated weather reporting station located at Cleburne Municipal Airport (CPT), located approximately 9 miles northwest of the accident site reported winds from 120 degrees at 4 knots, visibility 10 miles, skies clear, temperature 90 degrees Fahrenheit, dew point 72 degrees Fahrenheit and a barometric pressure of 29.96 inches of Mercury.