What happened
On May 7, 2011, an Alexander Schleicher ASW 20L glider, registration D-1110, was conducting a recreational flight. The flight began at Calcinate del Pesce airport, where the pilot departed at 10:00 UTC. The flight path initially took the aircraft north toward Mount Tamaro and then east toward Mount Bregagno, later crossing Lake Como toward Mount Legnone.
As environmental conditions became unfavorable for soaring, the aircraft began a progressive descent. The pilot reached a maximum altitude of 2,501 meters during the flight. Seeking an alternative landing site, the pilot targeted a known area near Porlezza. While maneuvering near a ridge north of the intended landing site, the pilot gained a small amount of altitude and decided to continue exploring the area in search of thermal lift to facilitate a return to the departure airport.
While turning south toward Porlezza, the glider encountered a ridge approximately 1,200 meters high. During this maneuver, the aircraft lost altitude and struck the treetops just beyond the ridge crest. The glider became lodged in the trees approximately two meters above the ground. The pilot was able to exit the cockpit without injury.
The investigation
The ANSV investigation utilized pilot statements and data logger analysis to reconstruct the flight sequence. The data logger revealed that as the D-1011 crossed the ridge heading south, its separation from the terrain was less than 100 meters. Examination of the wreckage showed that the aircraft dissipated most of its kinetic energy upon impacting the tree canopy. The impact resulted in substantial damage to the aircraft, including damage to both wing halves and a broken tail section that was bent downward at an angle of approximately 90 degrees.
Findings
- The primary cause of the accident was inadequate altitude maintained during the final phase of the flight, which prevented the pilot from safely clearing obstacles along the route.
- A contributing factor may have been a downdraft encountered near the ridge being traversed.