ASW 15 and LS 4 mid-air collision near Ritzihorn during alpine flight camp

On July 21, 1986, an Alexander Schleicher ASW 15 and a Rolladen-Schneider LS 4 collided mid-air near Ritzihorn, Switzerland, during an alpine flight camp. Both gliders were being flown individually and were towed to altitude before the incident. The collision occurred at approximately 2800 meters, resulting in both aircraft becoming uncontrollable and crashing. Unfortunately, both pilots were fatally injured, and the gliders were destroyed. The official investigation noted that the pilots saw each other too late to avoid the collision, and a reduction in the psycho-physical abilities of one pilot may have contributed.