Airworthiness Directives; Turbomeca S.A. Turboshaft Engines

We are superseding an existing airworthiness directive (AD) for Turbomeca S.A. Arrius 2B, 2B1, and 2F turboshaft engines. That AD currently requires replacement of injector manifolds and borescope- inspection of the flame tube and the high-pressure (HP) turbine area for possible damage. This new AD requires, depending on the engine model, repetitive replacements of fuel injection manifolds and the privilege injector, or, repetitive replacements of the privilege injector. This AD was prompted by a report that the corrective actions of the existing AD were insufficient to eliminate the unsafe condition. We are issuing this AD to prevent an uncommanded in-flight shutdown of Arrius 2B1 and 2F turboshaft engines and damage to the helicopter.