What happened
On July 18, 2020, a Schempp-Hirth Duo Discus T glider, registration D-KSEI, was performing a local soaring flight at Calcinate del Pesce airport. The glider was being towed by a powered aircraft, registration I-AEFF, with a pilot and a passenger on board.
Shortly after takeoff, the glider unexpectedly released from the tow cable at an altitude of approximately 40 meters. The pilot initially intended to maintain a straight course to perform a controlled water landing on Lake Varese, following standard procedures for low-altitude releases. However, during the maneuver, the aircraft entered a steep turn. The glider subsequently impacted the surface of the lake with its wing, followed by the nose. Both occupants managed to exit the aircraft uninjured and were rescued by boat, though the glider sustained significant damage and a nearby residential fence was also damaged.
The investigation
The ANSV investigation focused on the sequence of events leading to the release and the subsequent flight path. The investigation examined the pilot's statements, the passenger's account, the tow plane pilot's observations, and airport surveillance footage.
Analysis of the cockpit layout showed that the release mechanism is located near the pilot's inner upper left thigh. The pilot reported feeling sudden discomfort in that area and instinctively moving his leg, which likely caused the accidental activation of the release mechanism through his clothing.
Video evidence confirmed the sequence: the release occurred 23 seconds after takeoff, followed by a period of stable flight, and then a sharp left-hand turn at low altitude that preceded the impact. The investigation also noted a discrepancy in the cockpit management; while the pilot was the commander, there was evidence of conflicting maneuvers or instructions between the pilot and the passenger, who was a qualified pilot but acting only as a passenger.