What happened
On April 10, 2010, at approximately 10:30 UTC, a pilot was preparing an Alexander Schleicher ASW 19 glider, registration D-7946, for a training flight at Belluno Airport. After completing the assembly of the aircraft, the pilot proceeded to runway 23 for takeoff.
During the takeoff roll, at a speed of approximately 100-110 km/h, the glider assumed an abnormal, excessively high attitude relative to the towing aircraft. The pilot attempted to correct the pitch using the control stick, but the input only resulted in further pitch-up movement. Realizing the loss of effective pitch control, the pilot executed an emergency release from the tow plane. After verifying that roll and yaw controls remained functional, the pilot performed a controlled descent into a field south of the airport. The landing, which took place in an area with several depressions in the terrain, resulted in structural damage to the lower fuselage, cockpit, landing gear door, canopy locking mechanism, and the landing gear retraction mechanism. The pilot was uninjured.
The investigation
The ANSV investigation focused on the assembly process and the functionality of the flight controls. The investigation established that the pilot had performed the assembly himself, a process that was frequently interrupted by the need to assist other pilots and move the aircraft to accommodate simultaneous assemblies of other gliders.
Crucially, the investigation found that the elevator had not been properly connected to its control rod during the assembly. Due to the specific mechanics of the control linkage, a pitch-up command (compression) remained possible, but a pitch-down command (tension) failed because the disconnected rod was pulled away from its attachment point. The investigation also noted that the pilot's flight manual was in German, a language the pilot did not master perfectly, and that post-assembly checks were insufficient to detect the disconnected linkage.
Findings
- The primary cause of the incident was the failure to connect the elevator to the control rod during the assembly process.
- The assembly sequence was repeatedly interrupted, leading to a lack of concentration.
- Inadequate pre-flight and post-assembly inspections failed to identify the mechanical disconnection.
- Contributing factors included improper preparation for the assembly task and a high level of complacency regarding a seemingly routine procedure.
- The lack of organized space management during the assembly of multiple gliders contributed to the errors.