Incident Overview
On July 13, 2020, a training flight involving a SZD-9 bis 1E 'Bocian' glider, registration SP-3799, was conducted at Gliwice Airport (EPGL). The flight was part of a series of school glider operations using winch launches.
Sequence of Events
At approximately 19:46 local time, an instructor and a student performed a winch launch for exercise SPL/I, exercise 4: 'handling special and emergency situations.' The task was to interrupt the tow at an agreed height of about 30 meters, release the cable, and after securing airspeed, execute a straight-ahead landing by the student. However, the winch operator interrupted the tow at a height of approximately 60-70 meters. The instructor then took control, opened the airbrakes, and performed a slip to reduce altitude. However, the instructor assessed that the approach profile indicated that a straight-ahead landing would not allow the glider to stop within the airfield. Therefore, in the final phase of flight, the instructor executed a flat left turn to prevent the glider from rolling off the runway after touchdown. During the turn, the left wingtip made contact with the ground. The glider then landed with a yaw (travers) and came to a stop on the airport apron.
Damage and Injuries
The left wing's trailing edge was damaged during the landing. The crew sustained no bodily injuries and exited the cockpit unassisted.
Cause
The incident was attributed to attempting to land straight ahead from an improper height after an interrupted tow.
Prevention Measures
The glider operator decided to develop procedures (best practices) for handling interrupted tows at various heights during glider launches, taking into account the airport's takeoff field characteristics and terrain obstacles. The Polish State Commission on Aircraft Accident Investigation did not issue any safety recommendations.