Superseded. This AD was superseded by AD 2021-26-18. Verify which one applies to your serial and effectivity before any maintenance action.
AD 2020-21-01
Effective 11/12/2020 · Published 10/08/2020
Airworthiness Directives; Airbus Helicopters
Summary
The FAA is adopting a new airworthiness directive (AD) for certain Airbus Helicopters Model AS-365N2, AS 365N3, EC 155B, EC155B1, and SA-365N1 helicopters. This AD requires modifying the main gearbox (MGB) tail rotor (T/R) drive flange installation. This AD was prompted by several reported occurrences of loss of tightening torque of the Shur-Lok nut, which serves as a retainer of the T/R drive flange. The actions of…