What happened
On 29 June 2022, a Rolladen-Schneider LS1-d glider, registration D-2057, was performing a winch launch at the Terlet glider airfield. Immediately after becoming airborne, the aircraft entered a steep climb. At an altitude of approximately 20 meters, the glider experienced a slight roll to the right, followed by a sharp left-hand turn with a steep bank angle. The aircraft's nose then dropped, and it began a counter-clockwise rotation before crashing into the ground. The impact destroyed the aircraft and resulted in the fatal injury of the pilot.
The investigation
The Dutch Safety Board examined the wreckage and interviewed witnesses, including members of the local gliding club. The investigation included a technical review of the aircraft's flight controls, maintenance records, and the winch operation. Investigators also analyzed film recordings of the accident. The technical examination of the wreckage, assisted by a glider technician, found no evidence of mechanical failure in the flight control systems. Additionally, the investigation confirmed that the winch operated normally and the weight and balance of the aircraft were within prescribed limits.
Findings
- The primary cause of the accident was a stall that occurred at a very low altitude.
- The stall was triggered by a high rotation rate during the initial phase of the winch launch, which caused the aircraft to exceed its critical angle of attack.
- The pilot's subsequent control inputs led to a steep bank and a nose-down attitude, making recovery impossible due to the low height.
- While the pilot was experienced, his recent experience with composite gliders like the LS1-d was limited compared to older, more docile aircraft models.
Safety action
While the Dutch Safety Board noted that gliding clubs already emphasize safe winch launch procedures during training, the Board uses this report to highlight the inherent risks of the winch launch method. Specifically, it emphasizes the danger of stalling during the rotation phase and the necessity for all pilots, including experienced ones, to maintain a controlled, progressive climb to prevent such occurrences.