What happened
During cruise flight, the aircraft suffered a catastrophic failure involving the complete loss of the tail rotor system. Despite this significant mechanical failure, the pilot was able to land the helicopter successfully. The landing resulted in no additional damage to the airframe and no injuries were reported among those on board.
The investigation
A detailed examination of the failed components was conducted to determine the root cause of the incident. Investigators found that the failure originated from a fatigue crack located within the skin of one of the tail rotor blades. This structural defect allowed the blade to fail under operational loads, leading to the total loss of the system.
Findings
The manufacturer analyzed the manufacturing process used to produce the affected blades. They determined that a specific grinding process employed during production removed material from the tail rotor skin. This removal of material initiated the fatigue failure that ultimately led to the in-flight breakup of the tail rotor assembly.