What happened
On December 14, 2024, at approximately 13:00 local time, a Robinson R44 II helicopter engaged in a recreational flight near Llanada Grande, Chile. The flight began around 11:00 local time, departing from the vicinity of the Llanada Grande airstrip (SCLD). After visiting several lakes in the region, the aircraft landed at the shore of Lake Inexplorado at an altitude of 2,864 feet.
During the return leg of the flight, the aircraft crossed the Hornopirén National Park from south to north, reaching an altitude of approximately 5,000 feet. As the pilot initiated a descent toward the banks of the Traidor River, the pilot reported a loss of engine RPM. In an attempt to manage the situation, the pilot performed an emergency landing on a terrain composed of pebbles and sand within the riverbed. Upon impact, the aircraft slid across the surface and overturned onto its left side. All four occupants—the pilot and three passengers—were able to egress the aircraft on their own and sustained no injuries.
The investigation
DGAC Chile investigators examined the wreckage at the site and later at the Cañal Bajo Aerodrome in Osorno. The inspection of the Robinson R44 II revealed significant structural damage caused by the impact and rollover. The fuselage sustained multiple dents, and the left front windshield was shattered. The landing skids were fractured at the tips, and the rear cross-tube was detached from the fuselage. The impact also caused the tail cone to tear away from the main fuselage and the tail rotor to detach from the tail cone, with one tail rotor blade bent at a 90-degree angle.
Investigators also reviewed the aircraft's maintenance records, which showed that the engine and airframe were within their service limits, with the most recent annual inspection completed in December 2023. A fuel sample taken from the tanks showed blue 100LL aviation gasoline with no signs of contamination. Meteorological data for the time of the accident indicated clear skies with light winds, though investigators noted that local topography can induce upward and downward wind currents.
Findings
- The primary cause of the emergency landing was the indication of low engine RPM during the descent.
- The aircraft sustained substantial damage to the main rotor blades, tail rotor assembly, and landing gear due to the impact with the riverbed terrain.
- The aircraft was operating in a recreational capacity with a full load of four occupants.
- All safety equipment, including seatbelts and harnesses, functioned as intended, and the occupants escaped without injury.