What happened
On June 7, 1976, a training flight departed from Buochs airfield in a K 8 B glider, registration HB-818. The pilot, flying in a formation with another glider, initially climbed to approximately 1,100 meters using ridge lift. The two aircraft intended to fly toward the Walenstöcke region, with the less experienced pilot positioned in the rear of the formation.
While navigating the Engelberg Valley, the pilot of the HB-818 identified an updraft north of Chlei Gigi and turned left into the rising air. During this maneuver, the aircraft encountered a descending transport cable. The right wingtip struck the cable approximately one meter from the end of the wing, causing a large section of the wing structure to be torn away. The impact also dislodged the cockpit canopy. Following the structural failure, the glider plummeted, crashing near Chlei Gigi at an altitude of approximately 1,640 meters. The pilot suffered severe injuries, and the aircraft was destroyed.
The investigation
The investigation examined the pilot's qualifications, the aircraft's condition, and the environmental factors. The pilot had only begun flight training in March 1976 and had passed his solo flight exam just ten days prior to the accident. While he held a temporary permit to fly without an instructor, he had not yet completed the required 20 solo flights.
Technical inspections of the K 8 B revealed no pre-existing mechanical defects, and the aircraft's weight and balance were within limits. Regarding the obstacle, investigators determined that the transport cable was positioned 55 to 60 meters above the ground. Under existing regulations, such cables did not require marking or inclusion in aeronautical charts.
Findings
- The pilot failed to adequately prepare for the flight by checking for potential hazards along the intended route, which is critical in mountainous terrain.
- The pilot flew at an altitude of approximately 60 meters above ground level without verifying the absence of obstacles, suggesting a lack of familiarity with specific flight regulations.
- The pilot's extremely limited flight experience contributed to the inability to recognize and avoid the hazard.
- There was a lack of emphasis on the specific dangers posed by cables in training environments.