What happened
On December 29, 2021, at approximately 13:15 UTC, a Bell 412 EP helicopter, registration LV-KAI, was conducting a test flight of its external water bucket (bambi bucket) near Quillén, Neuquén. The aircraft had departed around 13:00 UTC as part of firefighting operations. During the flight, the helicopter entered the Las Bandurrias canyon. While maneuvering near the mountain crest, the loaded external bucket struck the eastern slope of the mountain. This impact caused the aircraft to lose control, following a parabolic trajectory that led it to strike the western slope of the same mountain. The aircraft subsequently hit a rock and crashed violently, resulting in a post-impact fire that completely destroyed the airframe. The two fatalities included the pilot and one passenger.
The investigation
The investigation focused on the flight path and the environmental conditions at the time of the accident. Investigators determined that the aircraft was flying in visual meteorological conditions but was subject to significant mountain weather effects. The flight path was reconstructed using three distinct impact points on the terrain. The investigation also examined the status of the external load, finding that the bambi bucket was not released via its emergency system during the 21 seconds between the initial impact and the final crash; instead, it was found beneath the wreckage.
Findings
- The primary trigger for the accident was the impact of the water-filled bambi bucket against the mountain slope.
- Severe mountain meteorology, characterized by wind shear and turbulence, likely contributed to the loss of altitude.
- Winds from the west were hitting the windward side of the mountain, creating descending air currents and turbulence on the leeward side where the helicopter was operating.
- The pilot was performing a test of the external load equipment and had notified the ground coordinator of this intention.
Safety action
- The investigation identified that an unauthorized individual, who held no aeronautical license and had no essential role in the flight, was present in the co-pilot seat, which does not comply with established regulations.