What happened
On May 21, 2016, a Centrair Pégase 101 glider, registration HB-1956, was performing a training flight at Neuchâtel Aerodrome (LSGN). The aircraft was being operated by the Groupe de Vol à Voile de Neuchâtel (GVVN) under the supervision of an instructor. During the takeoff roll on runway 05, the glider began to deviate from the runway centerline.
As the deviations from the midline increased, the student pilot decided to release the tow rope. Following the release, the glider continued to drift off the paved surface and entered the grassy area north of the runway. The aircraft entered a ground loop before coming to a halt. The lateral forces generated during this excursion caused the aircraft to be heavily damaged, specifically resulting in the delamination of the rear fuselage boom near the vertical stabilizer.
The investigation
SUST examined the circumstances surrounding the takeoff roll and the subsequent loss of directional control. The investigation focused on the flight path of the HB-1956 during the tow and the decision-making process of the student pilot. Investigators reviewed the aircraft's flight history, noting the pilot had very limited experience on this specific type, with only 8 previous flights totaling 1 hour and 21 minutes.
Findings
- The primary cause of the excursion was the uncontrolled deviation from the runway centerline during the takeoff roll.
- The student pilot's decision to release the tow rope was a response to the increasing magnitude of the aircraft's lateral drift.
- The structural failure, characterized by delamination of the fuselage tube approximately one meter from the tail, was a direct result of the lateral stresses applied to the airframe during the ground loop.