What happened
On July 12, 2015, a training flight was being conducted at the Pobiednik Wielki airfield near Krakow. The flight involved an SZD 9 Bis 1E Bocian glider performing a specific instructional maneuver (exercise 4, simulating emergency procedures). During the flight, the instructor simulated an engine failure/loss of tow during the initial takeoff phase. The glider successfully landed at an altitude of approximately 20 meters, coming to rest with a 15-20 degree deviation from the takeoff line.
While the crew remained seated in the cockpit following the landing, the winch operator began retrieving the tow cable. During this process, the loop of the winch cable rose and became entangled with the tail section of the aircraft. The impact caused significant damage to the glider's tail at the level of frame number 25, affecting both the horizontal and vertical stabilizers.
The investigation
The investigation focused on the actions of the winch operator and the physical dynamics of the cable retrieval. The commission examined the positioning of the cable loop and the environmental factors present during the retrieval process. The investigation also considered the physical properties of modern synthetic cables compared to traditional steel cables.
Findings
- The primary cause of the incident was the winch operator attempting to retrieve the cable without first ensuring the maneuver could be performed safely.
- A contributing factor was the difficulty the operator faced in assessing distances due to the necessity of looking directly into the sun.
- The investigation noted that the use of modern synthetic cables, which are lighter than older steel versions, increases the risk of the cable loop lifting into the air and drifting toward the aircraft during retrieval.
- The commission emphasized that winch operators must only begin retrieval after receiving explicit permission from the ground crew/square, as the operator cannot accurately judge the cable's position or potential hazards to nearby personnel and equipment.