AD NUMBER: 2018-20-23

PRODUCT: General Electric Company (GE) GE90-110B1 and GE90-115B turbofan engines with certain high-pressure compressor (HPC) rotor stage 2-5 spools installed.

ACTION: Final Rule.

SUMMARY: The FAA is superseding Airworthiness Directive (AD) 2017-07-04 for the engines listed above.

AD 2017-07-04 required removing certain HPC rotor stage 2-5 spools from service at times determined by a drawdown plan.

This AD requires removing certain HPC rotor stage 2-5 spools from service before reaching the new reduced life limit and replacing them with parts eligible for installation.

This AD was prompted by the publication of a GE service bulletin (SB) that increases the number of affected HPC rotor stage 2-5 spools and includes HPC rotor stage 2-5 spools that were inadvertently omitted from the applicability of AD 2017-07-04.

DATES: This AD is effective November 30, 2018.

COST: The FAA estimates that this AD affects 85 engines installed on airplanes of U.S. registry. Operators may incur the following costs in order to comply with this AD:

• Paragraph (g)(1) Spools Replacement - $229,737 per engine.
• Paragraph (g)(2) Spools Replacement - $39,048 per engine.

FMI: AD