Summary
On 7 April 2019, a student pilot flying a SZD-51-1 Junior glider from Warsaw Babice (EPBC) experienced a trimmer spring failure during a winch launch. After the glider reached release height, the student did not release the towline and began a turn. The winch operator cut the line, and the student subsequently released the towline and landed safely. No injuries were reported.
Occurrence
The student pilot had completed four training flights in a Puchacz glider earlier that day. He then flew one flight in the Junior glider with no issues noted by the supervising instructor. During the second flight in the Junior, while climbing, the trimmer spring broke. The glider reached a release height of approximately 300 meters, and the winch operator disengaged the tow. Despite the malfunction, the launch proceeded normally until release. The student transitioned to a glide but did not pull the towline release handle. He began a turn with the towline still attached. The winch operator repeatedly transmitted the command "Junior, release the line" over the radio, as did the flight director. When the student did not respond promptly, the winch operator cut the towline per procedure. The student then released the towline and completed a circuit, landing safely. The cut line with its drogue chute fell within the airfield area without causing a hazard.
Contributing Factors
The student pilot, a 50-year-old male with a total flight time of 48 hours 35 minutes (7 hours 30 minutes on the Junior), held a valid medical certificate and qualification. He had resumed winch launch flying on 30–31 March. The instructor noted that the student had previously released the towline correctly. After the incident, the student revealed that before the second flight, he had discussed glider hooks with self-release functionality with another student. He mistakenly assumed the Junior glider was equipped with a self-release hook and interpreted the trimmer spring failure as the self-release activating. He did not wait for confirmation of release and did not react to the radio commands.
Cause
The investigation identified two causes: (1) the student pilot's failure to release the towline, and (2) beginning the landing pattern without ensuring the towline was released. Contributing factors included the student's erroneous assumption that the glider had a self-release hook and the trimmer spring failure during takeoff.
Post-Incident Actions
The trimmer spring was replaced in accordance with maintenance documentation. The hooks were inspected and release forces measured with no issues. The student was instructed that regardless of hook type, he must pull the release handle three times and verify release. He was referred for technical training on both types of glider hooks. He completed a check flight and two training flights before being cleared for solo flight. The incident was published in a safety bulletin distributed to all club members. No safety recommendations were issued.