Airworthiness Directive · Amendment 39-16901 · General Electric Company (GE) GE90-110B1 and GE90-115B Turbofan Engines
General Electric Company (GE) GE90-110B1 and GE90-115B Turbofan Engines
This AD applies to General Electric Company (GE) GE90-110B1 and GE90-115B turbofan engines with high-pressure compressor (HPC) stages 2-5 spool, part number (P/Ns) 351-103-106-0, 351-103-107-0, 351-103-108-0, 351-103-109-0, 351-103-141-0, 351-103-142-0, 351-103-143-0, or 351-103-144-0, installed.
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.
Comply with this AD when the HPC forward case half is removed from the engine after the effective date of this AD, unless the actions have already been done.
Perform an eddy current inspection (ECI) or a fluorescent penetrant inspection (FPI) of the HPC stages 1-2 seal teeth using paragraphs 3.B. or 3.C. of GE Service Bulletin (SB) GE90-100 S/B 72-0320, Revision 02, dated October 1, 2010.
Remove from service HPC stages 2-5 spool with cracked stages 1-2 seal teeth before further flight.
An ECI or FPI inspection performed before the effective date of this AD using GE SB GE90-100 S/B 72-0320, Revision 02, dated October 1, 2010, or earlier revision, satisfies the inspection requirement of this AD.
(1) After the effective date of this AD, do not install or reinstall any HPC forward case unless it is equipped with either:
(i) HPC stator stage 1 interstage seals, P/N 351-109-503-0;
(ii) HPC stator stage 1 interstage seals, P/N 351-109-502-0, with the grooves on seals that meet the dimensional requirements defined in paragraph 3.D.(1) of GE SB GE90-100 S/B 72-360, Revision 04, dated November 7, 2011.
(iii) A mixture of the HPC stator stage 1 interstage seals listed in paragraphs (i)(1)(i) and (i)(1)(ii) of this AD.
