Airworthiness Directive · Amendment 39-21286 · Turbine section
General Electric Company Turbofan Engines
This AD applies to General Electric Company GE90-110B1 and GE90-115B model turbofan engines with:
(1) A high-pressure turbine (HPT) rotor stage 2 disk, part number (P/N) 2505M73P03, and serial number (S/N) TMT1BA38 or TMT1BA41, installed; or
(2) A rotating compressor discharge pressure (CDP) HPT seal, P/N 2479M03P01, and S/N GEE1H7GH or GEE1H7JJ, installed.
The FAA is adopting a new airworthiness directive (AD) for certain General Electric Company (GE) GE90-110B1 and GE90-115B model turbofan engines. This AD was prompted by the detection of melt-related freckles in the billet, which may reduce the life limits of certain high-pressure turbine (HPT) rotor stage 2 disks and certain rotating compressor discharge pressure (CDP) HPT seals. This AD requires the replacement of the affected HPT rotor stage 2 disks and rotating CDP HPT seals. The FAA is issuing this AD to address the unsafe condition on these products.
(1) Before the affected HPT rotor stage 2 disk or the rotating CDP HPT seal listed in Table 1 to paragraph (g) of this AD (“Table 1”) accumulates the cycles since new (CSN) threshold in Table 1, or at the next engine shop visit, whichever occurs first after the effective date of this AD, remove the affected part from service and replace it with a part eligible for installation.
(2) If the affected HPT rotor stage 2 disk or rotating CDP HPT seal has already exceeded the CSN threshold in Table 1, remove the affected part before further flight and replace with a part eligible for installation.
(1) For the purpose of this AD, a part eligible for installation is any HPT stage 2 disk or rotating CDP HPT seal with an S/N that is not listed in Table 1.
(2) For the purpose of this AD, an engine shop visit is the induction of an engine into the shop for maintenance involving the separation of pairs of major mating engine flanges, except that the separation of engine flanges solely for the purposes of transportation of the engine without subsequent engine maintenance does not constitute an engine shop visit.
