Airworthiness Directives; Eurocopter France Model AS-365N, N1, and N2 Helicopters

This amendment adopts a new airworthiness directive (AD), applicable to Eurocopter France Model AS-365N, N1, and N2 helicopters, that requires inspecting the helicopter to determine if a certain main rotor head frequency adapter (frequency adapter) is installed and, if so, replacing it with an airworthy frequency adapter. This amendment 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 this 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.