Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to Eurocopter France Model AS-365N, N1, and N2 helicopters, with certain main rotor head frequency adapters (frequency adapters) installed. This proposal would require inspecting the frequency adapter to determine if a certain frequency adapter is installed, and if so, removing and replacing the frequency adapter with an airworthy frequency adapter before further flight. This proposal is prompted by a report of disbonding of the metal center section of a frequency adapter from the elastomer on a main rotor head, caused by a lack of adherence during the production process. The actions specified by the proposed AD are intended to prevent increased vibrations caused by disbonding of the center section of a frequency adapter from the elastomer and subsequent reduced controllability of the helicopter.