SZD 30-C Pirat — tow rope didn't release, wing structural failure
On 10 July 2011 a Wilga 35 + SZD 30-C Pirat tow launched from Jena-Schöngleina, Germany. At ~600 m AGL the glider pilot called 'I'm free' but the rope had not released. The Wilga was pulled into a dive and recovered at ~300 m. The rope then broke — it lacked a proper metal weak link, only a tape-wrapped knot — and the Pirat's wing failed under overload during the pilot's abrupt recovery. The glider pilot was fatally injured; the Wilga landed safely.
- Aerotow climb: The Pirat glider was aerotowed by a Wilga 35 from Jena-Schöngleina and climbed normally to about 600 m toward the release area.
- Release misperceived: At about 600 m in the release area, the tow pilot signalled for release and the glider pilot transmitted “I am free,” although the tow rope in fact did not detach from the glider.
- Tow rope setup: The tow rope lacked a proper metal weak link and instead had a knot intended as an additional weak point, allowing the rope to reach a breaking load well above the glider’s specified 500 daN tow limit.
- Glider climbs to turn: Believing he was released, the glider pilot pulled up to initiate the standard right turn away from the tow plane as prescribed after tow release.
- Towplane forced dive: The still-attached rope tightened, pitching the Wilga’s tail up into a steep dive of about 300 m and initially pulling the glider downward, while the high rope tension prevented the glider pilot from releasing.
- Rope break and overload: The overstressed tow rope eventually broke at the glider end with an estimated load around 1 094 daN, after which the glider experienced loads that led to in‑flight structural failure of the wing center section and separation of major wing parts.
- Crash - fatal: The glider’s fuselage descended steeply and impacted terrain near Großlöbichau, fatally injuring the pilot and destroying the aircraft, while the towplane recovered from the dive and landed without damage.