What happened
On April 12, 2022, a Nimbus-4D glider, registration D-1380, crashed into a steep, heavily wooded slope on Monte Luta, Italy. The flight originated from Lienz, Austria, as part of a training excursion for a group of pilots from Germany. The aircraft was performing a local orientation flight when it struck the terrain at high speed.
At the time of the impact, the aircraft was flying at an altitude of approximately 2,060 meters, with only about 40 meters of clearance from the treetops. The impact was extremely violent, destroying the cockpit area and causing the tail boom to break away. Both pilots on board, a 17-year-old student and a 70-year-old instructor, sustained fatal injuries.
The investigation
The ANSV investigation focused on the flight parameters recorded by the onboard FLARM system and the physical evidence at the crash site. Investigators noted that the wreckage showed signs of an extremely steep dive, which was inconsistent with a mechanical failure but highly indicative of a loss of control.
Analysis of the FLARM data showed the glider was maneuvering to exploit weak thermal currents—often referred to as "blue thermals"—just before the signal was lost. The investigation also examined the flight experience of the crew, noting that the pilot in the front seat had limited experience with this specific aircraft type and had never flown in the Alps. Additionally, the instructor was recovering from recent hand surgery, which may have impacted his ability to intervene physically during a critical flight phase.
Findings
- The primary cause of the accident was likely a loss of control due to an asymmetric stall during a steep turn intended to capture weak lift.
- The altitude was insufficient to allow for a recovery maneuver following the stall.
- The pilot in the front seat lacked experience with the Nimbus-4D and had no prior experience flying in alpine terrain.
- Meteorological conditions provided only weak thermal activity, necessitating aggressive maneuvering.
- The instructor's ability to provide forceful control inputs may have been limited by a recent surgical procedure on his left hand.