Airworthiness Directive · Amendment 39-22157 · Turbine engine compressor section, and jasc code 7250, turbine section
General Electric Company Turbofan Engines
This AD applies to:
(1) General Electric Company (GE) GE90-110B1 and GE90-115B model turbofan engines; and
(2) GE GE90-76B, GE90-85B, GE90-90B, and GE90-94B model turbofan engines with an installed interstage high-pressure turbine (HPT) rotor seal with part number (P/N) 2629M47P01 and serial number (S/N) NCU5430D.
The FAA is adopting a new airworthiness directive (AD) for all General Electric Company (GE) GE90-110B1 and GE90-115B model turbofan engines and certain GE90-76B, GE90-85B, GE90-90B, and GE90-94B model turbofan engines. This AD was prompted by the detection of melt-related freckles in the forgings and billets, which may reduce the life of certain rotating compressor discharge pressure (CDP) high-pressure turbine (HPT) seals (rotating CDP seals), interstage HPT rotor seals, and HPT rotor stage 2 disks. This AD requires revising the airworthiness limitations section (ALS) of the applicable GE90-100 Engine Manual (EM) and the operator's existing approved maintenance program or inspection program, as applicable, to incorporate reduced life limits for these parts. This AD also requires the removal and replacement of certain interstage HPT rotor seals, identified by serial number (S/N), installed on GE90-76B, GE90-85B, GE90-90B, and GE90-94B model turbofan engines. The FAA is issuing this AD to address the unsafe condition on these products.
(1) For affected GE90-110B1 and GE90-115B model turbofan engines, within 90 days after the effective date of this AD, revise the airworthiness limitations section (ALS) of the existing GE90-100 Engine Manual (EM) and the operator's existing approved maintenance program or inspection program, as applicable, by inserting the following information:
(i) For rotating CDP seal P/N 2479M03P01, insert the information in Table 1 to paragraph (g)(1)(i) of this AD.
| Part name | Part No. | Life cycles |
|---|---|---|
| Seal, CDP | 2479M03P01, For part serial numbers NOT listed in SB 72-0851, latest revision | 15,000 |
| Seal, CDP | 2479M03P01, For part serial numbers listed in SB 72-0851, latest revision APPENDIX A Table 11 | 5,300 |
| Seal, CDP | 2479M03P01, For part serial numbers listed in SB 72-0851, latest revision APPENDIX A Table 12 | 10,400 |
| Seal, CDP | 2479M03P01, For part serial numbers listed in SB 72-0851, latest revision APPENDIX A, Table 13 | 13,900 |
(ii) For interstage HPT rotor seal P/N 2505M72P01, insert the information in Table 2 to paragraph (g)(1)(ii) of this AD.
| Part name | Part No. | Life cycles |
|---|---|---|
| Seal, Interstage | 2505M72P01, For part serial numbers NOT listed in SB 72-0851, latest revision | 15,000 |
| Seal, Interstage | 2505M72P01, For part serial numbers listed in SB 72-0851, latest revision APPENDIX A Table 8 | 5,500 |
| Seal, Interstage | 2505M72P01, For part serial numbers listed in SB 72-0851, latest revision APPENDIX A Table 9 | 10,900 |
| Seal, Interstage | 2505M72P01, For part serial numbers listed in SB 72-0851, latest revision APPENDIX A Table 10 | 14,300 |
(iii) For HPT rotor stage 2 disk P/N 2505M73P03, insert the information in Table 3 to paragraph (g)(1)(iii) of this AD.
| Part name | Part No. | Life cycles |
|---|---|---|
| Disk, Stage 2 | 2505M73P03, For part serial numbers NOT listed in SB 72-0851, latest revision | 15,000 |
| Disk, Stage 2 | 2505M73P03, For part serial numbers listed in SB 72-0851, latest revision APPENDIX A Table 1 | 3,500 |
| Disk, Stage 2 | 2505M73P03, For part serial numbers listed in SB 72-0851, latest revision APPENDIX A Table 2 | 5,100 |
| Disk, Stage 2 | 2505M73P03, For part serial numbers listed in SB 72-0851, latest revision APPENDIX A Table 3 | 5,800 |
| Disk, Stage 2 | 2505M73P03, For part serial numbers listed in SB 72-0851, latest revision APPENDIX A Table 4 | 7,200 |
| Disk, Stage 2 | 2505M73P03, For part serial numbers listed in SB 72-0851, latest revision APPENDIX A Table 5 | 8,000 |
| Disk, Stage 2 | 2505M73P03, For part serial numbers listed in SB 72-0851, latest revision APPENDIX A Table 6 | 8,300 |
| Disk, Stage 2 | 2505M73P03, For part serial numbers listed in SB 72-0851, latest revision APPENDIX A Table 7 | 8,800 |
(2) For affected GE90-76B, GE90-85B, GE90-90B, and GE90-94B model turbofan engines, before the interstage HPT rotor seal, P/N 2629M47P01 and S/N NCU5430D, accumulates 7,400 cycles since new, remove the affected interstage HPT rotor seal from service and replace with a part eligible for installation.
For the purpose of this AD, a “part eligible for installation” is any interstage HPT rotor seal that does not have P/N 2629M47P01 and S/N NCU5430D.
