AD NUMBER: 2018-22-07

PRODUCT: All Engine Alliance (EA) GP7270, GP7272, and GP7277 model turbofan engines.

ACTION: Final rule; request for comments.

SUMMARY:  This AD requires inspection of the stage 6 seal ring for correct installation and inspection of the high-pressure compressor (HPC) stages 2-5 spool for cracks.

This AD also requires replacement of the HPC stages 2-5 spool if the stage 6 seal ring is incorrectly installed or if the HPC stages 2-5 spool is found cracked.

This AD was prompted by a shop finding of axial cracks in the interstage 5-6 seal teeth of the HPC stages 2-5 spool spacer arm, due to an incorrectly installed stage 6 seal ring.

DATES: This AD is effective January 11, 2019. Comments must be received by February 11, 2019.

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

• Borescope inspection of stage 6 seal ring and interstage 5-6 seal teeth forward and aft faces only: 4 work-hours × $85 per hour = $340 per aircraft.
• Replacement of HPC stages 2 to 5 spool: 8 work-hours × $85 per hour = $680. Parts: $346,540. Cost per airplane: $347,220.

FMI: AD