AD NUMBER: 2011-26-11

MANUFACTURER: General Electric Company
SUBJECT: GE90- 110B1 and GE90-115B Turbofan Engines

ACTION: Final rule.

SUMMARY: We are adopting a new airworthiness directive (AD) for the products listed above, with certain part number (P/N) high-pressure compressor (HPC) stages 2-5 spools installed. This AD was prompted by an aborted takeoff caused by liberation of small pieces from the HPC stages 1-2 seal teeth and two shop findings of cracks in the seal teeth. This AD requires eddy current inspection (ECI) or spot fluorescent penetrant inspection (FPI) of the stages 1-2 seal teeth of the HPC stages 2-5 spool for cracks. This AD only allows installation of either HPC stator stage 1 interstage seals that are pregrooved or previously worn seals with acceptable wear marks to prevent heavy rubs. We are issuing this AD to detect cracks in the HPC stages 1-2 seal teeth due to heavy rubs that could result in failure of the seal of the HPC stages 2-5 spool, uncontained engine failure, and damage to the airplane.

DATES: This AD is effective February 3, 2012. The Director of the Federal Register approved the incorporation by reference of a certain publication listed in the AD as of February 3, 2012.

FMI: http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAD.nsf/Frameset?OpenPage