On August 17, 2012, about 1520 central daylight time, a Schleicher ASG29-15M, French registration F-CIFB, collided in midair with another Schleicher ASG29-15M, German registration D-6080, about 18 miles southwest of Garner Field (KUVA), Uvalde, Texas. The pilot of F-CIFB was not injured. The glider sustained minor damage. The pilot of D-6080 sustained minor injuries. The glider was substantially damaged. Both gliders were registered to and operated by their respective pilots under the provisions of 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed at the time of the accident, and no flight plans had been filed. The local flights originated from KUVA approximately 1330.

Both pilots were competing in the 15-meter class of the 32nd World Gliding Championship. According to the pilot of F-CIFB, he was circling about 30 kilometers (18 miles) west-southwest of Uvalde at an altitude of 1,800 to 1,900 meters (5,906 to 6,234 feet). He said D-6080 was about 100 meters (328 feet) below him in a thermal. He said one turn later, D-6080 was about 20 meters (66 feet) below him. He noted that D-6080 was in a good "bubble" (thermal), so he maneuvered his glider into the same bubble. He said he was about 100-150 meters (328 to 492 feet) behind D-6080. As he was about to complete a thermal turn, he heard the proximity alarm sound "BELOW," and felt a strong impact. He saw D-6080 falling in two pieces: the tail, and the wings and canopy. He observed the pilot bail out. At about this time, water from the ballast came into his cockpit. He returned to KUVA and landed uneventfully.

According to the pilot of D-6080, he was climbing with several other gliders in a strong thermal when he was struck from behind by F-CIFB. He said he did not see the glider and was unaware of its presence. The collision occurred about 5,700 feet msl (above mean sea level). D-6080 pitched over inverted when the collision severed its tail assembly. The pilot jettisoned the canopy, exited the glider at about 4,000 feet agl (above ground level), and parachuted to safety. He watched his glider as it spiraled down. He landed in a rough field and was rescued about 90 minutes later.

A Federal Aviation Administration inspector from the San Antonio Flight Standards District Office responded to the accident site. He observed that the empennage of D-6080 had been severed and was located some distance from the main body of wreckage. Collision signatures on both gliders were consistent with D-6080 being struck from below and behind by F-CIFB. His examination of F-CIFB revealed minor damage to its left wing.

According to FAA's "Glider Flying Handbook," collision avoidance is of primary importance when thermalling with other gliders. All gliders in a particular thermal should circle in the same direction. The first glider in a thermal should establish the direction of turn and all other gliders joining the thermal should turn in the same direction. Two gliders in the same thermal at the same height or nearly so should position themselves across from each other so they can best maintain visual contact. A glider entering a thermal should not interfere with other gliders already in the thermal and not cause a hazard to other gliders.