Summary
The FAA proposes to adopt a new airworthiness directive (AD) for certain CFM International, S.A. (CFM) Model LEAP-1A and LEAP-1C engines. This proposed AD was prompted by an investigation of an in- flight shut down event that determined the aft arm of the high-pressure turbine (HPT) rotor interstage seal had failed. This proposed AD would require 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, this proposed AD will also prohibit installation of these affected parts onto any LEAP-1A or LEAP-1C engine. The FAA is proposing this AD to address the unsafe condition on these products.