What happened
On August 5, 2018, at Aleksandrowice (EPBA) airfield, an SZD-9 bis 1E Bocian glider, registration SP-3102, was performing a winch launch. During the initial climb, at an altitude of approximately 10 to 15 meters, the winch operator terminated the tension. The operator reported hearing a command to stop via radio, though this communication was not heard by the flight controller or other personnel on the ground. Due to a depleted battery, the pilot was operating without onboard radio communications.
Following the loss of tension, the glider continued into a steep climb before losing airspeed. The pilot, perceiving the drop in power as a temporary slackening of the line rather than a full termination, delayed the decision to release the cable. This delay led to a loss of lift and a subsequent stall. The glider entered an unintended left-hand autorotation, striking the ground with its left wing. The impact caused significant damage to the cockpit, the left wing, and the fuselage structure, but the pilot and passenger escaped without injuries.
The investigation
The PKBWL investigation examined the mechanical state of the SZD-9 bis 1E Bocian, the winch operations, and the communication environment. The investigation established that the aircraft was airworthy and that the weather conditions were appropriate for flight. Investigators noted that the winch operator was using a handheld radio without a headset due to a malfunction in the primary station, which likely led to the misinterpretation of radio commands due to ambient noise. The investigation also found that the pilot's lack of radio contact prevented him from receiving any information regarding the operator's decision to stop the winch.
Findings
- The primary cause of the accident was pilot error involving a delayed reaction to the loss of winch tension.
- The pilot's lack of onboard radio communication prevented him from being aware of the operator's intent to terminate the launch.
- The nature of the winch termination was not sudden or dynamic, which made it difficult for the pilot to immediately recognize the loss of power.
- The pilot's decision to maneuver the aircraft into a specific impact configuration—using the left wing to absorb energy—successfully prevented injuries to the occupants.