Airworthiness Directive · Amendment 39-19423 · Turbine engine turbine section
General Electric Company Turbofan Engines
This AD applies to all General Electric Company (GE) CF34-10A16, CF34-10E2A1, CF34-10E5, CF34-10E5A1, CF34-10E6, CF34-10E6A1, CF34-10E7, and CF34-10E7-B turbofan engines with high-pressure turbine (HPT) front rotating air seals listed in Appendices A and B, of GE CF34-10E Service Bulletin (SB) 72-0347 R00, dated August 3, 2018, that were not inspected and repaired using GE CF34-10E SB 72-0347 R00, dated August 3, 2018.
We are adopting a new airworthiness directive (AD) for all General Electric Company (GE) CF34-10A16, CF34-10E2A1, CF34-10E5, CF34- 10E5A1, CF34-10E6, CF34-10E6A1, CF34-10E7, and CF34-10E7-B turbofan engines with certain high-pressure turbine (HPT) front rotating air seals. This AD requires replacement of the affected HPT front rotating air seal. This AD was prompted by cracks found in the HPT front rotating air seal. We are issuing this AD to address the unsafe condition on these products.
(1) Remove the HPT front rotating air seal listed in Appendix A, of GE CF34-10E SB 72-0347 R00, dated August 3, 2018, and replace with a part eligible for installation within the following cycles:
(i) If the HPT front rotating air seal has 17,499 cycles since new (CSN) or more on the effective date of this AD, remove within 250 cycles in service (CIS).
(ii) If the HPT front rotating air seal has 16,500 to 17,498 CSN on the effective date of this AD, remove within 500 CIS but not to exceed 17,750 CSN.
(iii) If the HPT front rotating air seal has 15,500 to 16,499 CSN on the effective date of this AD, remove within 750 CIS but not to exceed 17,000 CSN.
(iv) If the HPT front rotating air seal has 14,500 to 15,499 on the effective date of this AD, remove within 1,000 CIS but not to exceed 16,250 CSN.
(v) If the HPT front rotating air seal has 12,800 to 14,499 on the effective date of this AD, remove within 1,500 CIS but not to exceed 15,500 CSN.
(vi) If the HPT front rotating air seal has 10,800 to 12,799 CSN on the effective date of this AD, remove within 2,000 CIS but not to exceed 14,300 CSN.
(vii) If the HPT front rotating air seal has 8,450 to 10,799 CSN on the effective date of this AD, remove within 2,500 CIS but not to exceed 12,800 CSN.
(viii) If the HPT front rotating air seal has fewer than 8,450 CSN on the effective date of this AD, remove at next piece-part exposure or before accumulating 10,950 CSN, whichever comes first.
(2) Remove the HPT front rotating air seal, listed in Appendix B, of GE CF34-10E SB 72-0347 R00, dated August 3, 2018, from service and replace with a part eligible for installation before exceeding the CSN listed in Appendix B, of GE CF34-10E SB 72-0347 R00, dated August 3, 2018.
(1) For the purpose of this AD, a part that is “eligible for installation” is defined as:
(i) An HPT front rotating air seal with a part number (P/N) and serial number (S/N) that is not listed in Appendix A or B, of GE CF34-10E SB 72-0347 R00, dated August 3, 2018; or,
(ii) an HPT front rotating air seal with a P/N and S/N listed in Appendix A or B, of GE CF34-10E SB 72-0347 R00, dated August 3, 2018, that was inspected and repaired using GE SB CF34-10E SB 72-0347 R00, dated August 3, 2018.
(2) For the purpose of this AD, “piece-part exposure” is defined as the separation of the HPT front rotating air seal from the disk.
