Airworthiness Directives; CFM International, S.A. Engines

The FAA is adopting a new airworthiness directive (AD) for certain CFM International, S.A. (CFM) Model LEAP-1A and LEAP-1C engines. This AD was prompted by an investigation of an in-flight shut down event that revealed the aft arm of the high-pressure turbine (HPT) rotor interstage seal had failed. This AD requires removal from service and replacement of the HPT rotor interstage seal for LEAP-1A engines. Since the HPT rotor interstage seal part number is interchangeable between LEAP-1A and LEAP-1C engines, this AD also prohibits installation of these affected parts onto any LEAP-1A or LEAP-1C engine. The FAA is issuing this AD to address the unsafe condition on these products.