What happened
On July 20, 2003, at approximately 12:35 local time, a PIK 20E motor glider, registration G-BGZL, was participating in a flight from Caiolo to Asiago. The aircraft took off following another motor glider, with the intent of utilizing thermal currents along the northern slopes of the Valtelluna mountains.
While the first aircraft successfully intercepted a rising current near Vèndolo, the pilot of the second aircraft, G-BGZL, flew toward the outskirts of Castione. Seeking thermal activity, the pilot attempted to turn toward the area between Mount Rolla and Mount Caldenno. During this maneuver, the aircraft encountered a sudden and powerful localized wind effect caused by the funneling of air between the two mountain peaks.
As the aircraft entered this narrow corridor, it was subjected to a strong tailwind component that pulled the glider into the canyon. In an attempt to avoid the terrain and steer toward the safety of Castione, the pilot executed a sharp right-hand turn. This aggressive maneuver, performed at a high bank angle, caused the aircraft to enter a descending trajectory and an incipient autorotation. The glider struck trees with its right wing at a nearly 90-degree bank angle, causing the airframe to break apart before finally impacting a rocky outcrop. The pilot sustained injuries that led to their death several days later.
The investigation
The ANSV investigation examined the flight paths of both aircraft, the local topography, and the microclimatic conditions of the site. Investigators analyzed the wreckage distribution and the impact marks on the terrain to reconstruct the final moments of the flight. The investigation also reviewed the pilot's flight experience and the technical status of the PIK 20E, noting that the aircraft was within its weight and balance limits and had undergone a recent 50-hour inspection.
Findings
- The loss of control by the pilot during a turn was the primary cause of the accident.
- The pilot was operating in an environment of extreme microclimatic variability, specifically encountering channeled wind within a natural funnel formed by the mountains.
- The sudden tailwind component within the canyon forced the aircraft into a dangerous flight path.
- The pilot's attempt to correct the situation with a high-load, high-bank turn resulted in a loss of altitude and a descending flight path.
- Contributing factors included an inadequate assessment of the local microclimate and flying at an altitude that did not allow sufficient margin for error in a high-risk zone.