Action
Final rule.
Summary
The FAA is superseding airworthiness directive (AD) for 2021- 05-05 which applied to all Airbus Helicopters Model SA-365N1, AS-365N2, AS 365 N3, SA-366G1, EC 155B, and EC155B1 helicopters. AD 2021-05-05 required modifying the helicopter by replacing the tail rotor gearbox (TGB) control shaft guide bushes; repetitive inspections (checks) of the oil level of the TGB and, if necessary, filling the oil to the maximum level; repetitive inspections of the TGB magnetic plug and corrective actions if necessary; repetitive replacements of a certain control rod double bearing (bearing); and modifying the helicopter by replacing the TGB. This AD was prompted by a report where during a landing phase, a helicopter lost tail rotor pitch control, which was caused by significant damage to the TGB bearing. This AD retains some of the requirements of AD 2021-05-05, and reduces the intervals of the magnetic plug inspection, revises the corrective actions if particles are detected, and revises the compliance time for replacement of the affected part, as specified in a European Union Aviation Safety Agency (EASA) AD, which is incorporated by reference. The FAA is issuing this AD to address the unsafe condition on these products.