What happened
During an approach to a landing site on Moa Island, a helicopter experienced a loss of control following a tail rotor strike. The landing site, which featured an elevated 4 m square helipad designed to compensate for sloping ground, lacked touchdown or positioning markings to assist the pilot. Due to heavy rainfall and the tropical environment, grass had grown over the compacted gravel surface of the pad. This vegetation obscured the helipad's boundaries from the pilot's view during the approach.
As the pilot maneuvered within the confined area, a discrepancy developed between the pilot's perception of the aircraft's position and its actual location. This resulted in the tail rotor making contact with a tree or branch. The impact caused significant damage to the tail rotor blades, leading to a tail rotor failure, rapid rotation of the aircraft, and a subsequent collision with the terrain. The pilot sustained injuries and was briefly rendered unconscious when their helmet struck the internal structure of the aircraft during the impact.
The investigation
Investigators examined the tail rotor blades and found no evidence of pre-existing damage, noting that the damage on both blades was consistent with an impact occurring under power. The discovery of woody, fibrous material within the inner structure of the blades supported the conclusion that the rotor had struck a tree.
Regarding occupant safety, the investigation noted that the pilot was wearing an approved flight helmet, which likely prevented more severe head injuries. However, the aircraft was not equipped with upper torso restraints (UTRs) in the rear seats. During the rapid rotation of the accident, the lack of such restraints contributed to the movement of passengers' limbs, with one passenger's arm and leg being thrown out of the open door and another passenger sustaining an injury from the damaged aircraft structure.