Airworthiness Directives; Safran Helicopter Engines

The FAA is withdrawing an NPRM that proposed to adopt a new airworthiness directive (AD) that would have applied to all Safran Helicopter Engines, S.A. (Safran) Model ARRIUS 2F and ARRIUS 2R engines. The NPRM was prompted by a manufacturer investigation that revealed certain high-pressure (HP) turbine blades may contain non- compliant porosity rates due to a change in the manufacturing process. The NPRM would have required replacement of affected HP turbine blades. Since the NPRM was issued, further investigation and tests demonstrated that the non-compliant rate of porosity has no impact on the use limit of the affected parts and the FAA has determined that the unsafe condition no longer exists. Accordingly, the NPRM is withdrawn.