What happened
On September 25, 2020, at Pobiednik Wielki Airport (EPKP), a training flight was being conducted using an SZD-9 bis 1E “Bocian” glider. The flight was intended to be a winch-launch session involving an instructor and a student.
At approximately 14:10 local time, following ground preparations, the crew boarded the aircraft. This was the instructor's eighteenth flight of the day in this specific glider. After attaching the winch cable and performing pre-flight checks, the instructor noticed that the elevator was not moving through its full range of motion. Recognizing the aircraft was unserviceable, the instructor disconnected the cable and notified the maintenance personnel of the malfunction.
The investigation
The PKBWL investigation focused on identifying the cause of the restricted elevator movement. Maintenance personnel performed a thorough inspection of the aircraft's control systems. The investigation established that the elevator pushrod was being physically obstructed. The obstruction was identified as a pen cap located under the pushrod bolt within the aileron control unit, situated at the height of the second cockpit's control stick.
Once the pen cap was removed, subsequent checks confirmed that the glider's control systems were functioning correctly.
Findings
- The primary cause of the incident was the accidental leaving of a foreign object (a pen cap) inside the cockpit.
- The position of the object within the control mechanism prevented the elevator from reaching its full deflection range.
- The circumstances regarding how the object was left in the cockpit were not determined.