Airworthiness Directives; Airbus Helicopters

The FAA is adopting a new airworthiness directive (AD) for all Airbus Helicopters Model EC 155B, EC155B1, SA-365N, SA-365N1, AS-365N2, and AS 365 N3 helicopters. This AD prompted by an engine compartment fire where the upper stiffener of the central firewall in the engine compartment was found damaged. This AD requires replacing the aluminum central firewall stiffener with a titanium central firewall stiffener and prohibits installing an aluminum central firewall stiffener. These actions are 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.