What happened
The accident occurred during the initial phase of flight. As the helicopter lifted off from the ground, it sustained a sudden loss of tail rotor drive. This mechanical failure resulted in the immediate loss of anti-torque control, which is critical for maintaining directional stability during vertical ascent and low-speed maneuvering.
The investigation
Following the incident, investigators conducted an extensive research and analysis program to determine the root cause of the mechanical failure. The examination focused on the integrity of the tail rotor drive system. Investigators discovered that a bonding within a shaft coupling had failed. This specific component is essential for transmitting torque and maintaining the structural continuity of the drive train.
Findings
The investigation team scrutinized multiple potential contributing factors to ensure no other elements were involved in the failure. They reviewed the design specifications, production records, quality assurance protocols, maintenance logs, and the operating environment. The analysis revealed no discrepancies in any of these areas that could have resulted in the coupling failure. Furthermore, historical data showed that only one previous occurrence of this specific type of failure had been documented, and it involved an assembly from a different vendor. This suggests the failure was likely an isolated incident rather than a systemic design flaw or maintenance error.