What happened
On August 18, 1998, during the "Bavaria Glide 1998" competition, two gliders collided near Bayreuth, Germany. The aircraft involved were a Schempp-Hirth Discus b and a Schleicher ASW-27. At the time of the incident, approximately 10 to 15 gliders were flying in left-hand circles within an updraft field at an altitude of roughly 1,000 meters.
The pilot of the ASW-27 was flying in the upper third of the formation, approximately 150 degrees offset from the other aircraft, with a bank angle of 15-20 degrees. The pilot observed the Discus b fly through the center of the circle and then turn left. This maneuver resulted in a collision between the left wing of the Discus b and the cockpit area of the ASW-27.
Following the impact, the left outer wing of the Discus b detached, causing the water tank in the wing to empty and sending the aircraft into a spiral dive. The Discus b struck a grassy slope with a longitudinal pitch of approximately 90 degrees, resulting in the death of one person and the total destruction of the aircraft. The pilot of the ASW-27 sustained one injury (minor), and the aircraft landed heavily damaged.
The investigation
Investigators from the BFU examined the wreckage and analyzed data from GPS loggers recovered from the scene. While the logger in the Discus b was destroyed by the impact, the logger from the ASW-27 provided data that confirmed witness accounts.
Physical examination of the ASW-27 revealed impact marks on the canopy and a dent on the right wing caused by the wing of the Discus b. In the wreckage of the Discus b, investigators found that the pilot's seatbelt was in an open position. The investigation also noted that the red control knob for the canopy emergency release was missing from the right side of the lever, though the thread remained undamaged.
Medical examinations of the deceased pilot showed no evidence of health issues that could have contributed to the accident, and the pilot of the ASW-27 tested negative for alcohol.
Findings
- The primary cause of the accident was that the pilot of the Discus b failed to recognize or did not recognize in time the presence of the other glider, subsequently flying into its flight path.
- The collision caused the immediate structural failure of the Discus b's left wing, leading to an unrecoverable spiral dive.
- While an emergency egress via the canopy release and parachute was theoretically possible given the altitude, the high G-forces experienced during the spiral dive may have prevented the pilot from executing the necessary actions.