What happened
On November 19, 2024, a commercial helicopter flight involving the transport of three passengers experienced a significant loss of control while attempting to land in the Mañihuales sector of the Ays/én Region. The Eurocopter AS350 B3, registration not specified, was performing a non-scheduled passenger flight between Mañihuales and El Gato.
During the final approach to the landing site, at an altitude of approximately 10 meters AGL, the pilot experienced a sudden pedal jam and a loss of tail rotor efficiency. This resulted in the aircraft entering a 360-degree vertical rotation. To regain control, the pilot executed an autorotation procedure, which stabilized the aircraft but ultimately led to a hard landing. Despite the impact, the pilot and the passenger were uninjured, though the aircraft sustained substantial structural damage to the landing gear, tail boom, and fuselage.
The investigation
DGAC Chile investigators examined the aircraft's maintenance history, the flight conditions, and the cockpit configuration. The investigation focused on why the anti-torque pedals became immobilized during a critical phase of flight.
Investigators discovered that two of the three retaining clips for the circuit breaker panel cover on the central pedestal were missing. This allowed the panel to shift and interfere with the movement of the anti-torque pedals. Testing confirmed that while the anti-torque system was functionally sound, the presence of the loose panel cover could—and did—cause pedal blockage. Furthermore, the investigation noted that the aircraft was operating within the "avoidance zone" of the height-velocity diagram, which prevented the pilot from performing a safe go-around once the loss of control occurred.
Findings
- The primary cause of the accident was a loss of control in flight (LOC-I) within the height-velocity avoidance zone, triggered by the obstruction of the yaw control pedals.
- The interference was caused by the circuit breaker panel cover shifting into the path of the pedals.
- Two retaining clips for the panel cover were missing at the time of the event.
- The aircraft's pre-flight inspection checklist did not explicitly require the verification of the circuit breaker panel's retaining clips.
- The manufacturer, Airbus Helicopters, had previously issued an Information Notice (N° 3322-I-39) warning of potential pedal interference caused by this specific component.