AD NUMBER: 2018-20-01

PRODUCT: All CFM International S.A. (CFM) LEAP-1B21, LEAP-1B23, LEAP-1B25, LEAP-1B27, LEAP-1B28, LEAP-1B28B1, LEAP-1B28B2, LEAP-1B28B2C, LEAP-1B28B3, LEAP-1B28BBJ1, and LEAP-1B28BBJ2 turbofan engines with a certain high-pressure turbine (HPT) stator case (HPT cases) installed.

ACTION: Final rule; request for comments.

SUMMARY: This AD requires removal of affected HPT cases from service and their replacement with a part eligible for installation.

This AD was prompted by the discovery of a quality escape at a manufacturing facility involving unapproved welds on HPT cases.

DATES: This AD is effective December 17, 2018.

COST: The FAA estimates that this AD affects two engines installed on airplanes of U.S. registry. Operators may incur the following costs in order to comply with this AD:

• Remove HPT case and FPI of forward flange - 1000 work-hour × $85 per hour = $85,000. Parts - $179,400. Cost per engine - $264,400.
• Replace combustion case assembly - 10 work-hours × $85 per hour = $850. Parts - $558,800. Cost per engine - $559,650.

FMI: AD