Summary
The FAA proposes to supersede Airworthiness Directive (AD) 2020-21-01, which applies to certain Airbus Helicopters Model AS-365N2, AS 365N3, EC 155B, EC155B1, and SA-365N1 helicopters. AD 2020-21-01 requires modifying the main gearbox (MGB) tail rotor (T/R) drive flange installation. Since the FAA issued AD 2020-21-01, the FAA has determined that additional helicopters are affected by the unsafe condition. This proposed AD would continue to require modifying the MGB T/R drive flange installation, and would also include new helicopters in the applicability for the required actions. The FAA is proposing this AD to address the unsafe condition on these products.