What happened
On April 23, 2023, at approximately 12:15 local time, a Robinson R44 II helicopter was conducting a cross-country flight in the mountainous La Parva sector of Lo Barnechea, Chile. The aircraft was carrying a pilot and two passengers. As the crew attempted to approach a landing site in the Andes, the helicopter struck a 10-meter-high hillside. The impact caused the main rotor blades to strike the terrain, after which the aircraft continued into a perimeter fence of a local sports field, where it finally came to rest.
Despite the force of the impact, the pilot and both passengers escaped the wreckage without injury. The aircraft sustained extensive damage, including a deformed fuselage, fractured windshield, and structural failure of the tail boom and landing gear. The main rotor blades were also heavily damaged, with one blade fracturing upon impact.
The investigation
DGAC Chile investigators examined the wreckage, the pilot's credentials, and the aircraft's maintenance history. The investigation confirmed that the aircraft's engine and mechanical systems were properly maintained, with the most recent 50-hour inspection completed shortly before the accident. The fuel, 100LL Avgas, was found to be clean and free of contaminants.
Investigators also reviewed the environmental conditions and operational parameters. At the time of the accident, the weather was clear with high pressure and visibility without restrictions. However, a critical discrepancy was identified regarding the operational altitude. The investigation compared the aircraft's actual altitude at the time of the event against the performance limitations outlined in the manufacturer's flight manual.
Findings
- The aircraft was operating at an elevation of 8,680 feet.
- The operating altitude exceeded the maximum limit of 7,000 feet specified for the aircraft's performance parameters.
- The impact with the hillside caused the primary structural damage to the rotor system and tail assembly.
- The landing gear sustained fractures due to instantaneous overstress during the impact sequence.