What happened
On August 1, 2018, an SZD-50-2 Perkoz glider was conducting winch-assisted training flights at the Biała Podlaska (EPBP) airfield. The flight was part of a student pilot's training program, specifically focusing on takeoff, circuit building, and landing maneuvers. The crew, consisting of an instructor and a student, completed the flight and landed on the concrete runway at 12:3 and PM (LMT).
Upon exiting the cockpit after the landing roll, the crew discovered that the main landing gear, including its suspension, had retracted into the fuselage. All previous landings performed that day on the same runway had been normal. Weather conditions were favorable, with a light wind of approximately 2 m/s along the runway axis.
The investigation
The investigation was conducted by the operator's commission. Following the incident, the aircraft was moved to a hangar, and the Continuing Airworthiness Management Organization (CAMO) and the Type Certificate Holder (TCH) were notified.
Upon disassembly of the landing gear, investigators found that the metal components of both elastomeric shock absorbers had fractured. A subsequent inspection by a representative of the TCH revealed no structural damage to the composite airframe, wings, empennage, or the landing gear bay truss. The maintenance organization subsequently replaced the broken shock absorbers with new units and performed a full inspection of the glider in accordance with approved guidelines.
Findings
- The primary cause of the incident was the fatigue failure of the main landing gear's elastomeric shock absorbers.
- A contributing factor may have been previous hard landings during the aircraft's operation, which likely initiated the fatigue cracking process.