Airworthiness Directive · Amendment 39-22034 · Compressor bleed valve
General Electric Company Turbofan Engines
This AD applies to General Electric Company (GE) CF34-8C1, CF34-8C5, CF34-8C5A1, CF34-8C5B1, CF34-8C5A2, CF34-8C5A3, CF34-8E2, CF34-8E2A1, CF34-8E5, CF34-8E5A1, CF34-8E5A2, CF34-8E6, and CF34-8E6A1 model turbofan engines.
The FAA is superseding Airworthiness Directive (AD) 2019-22- 05, which applied to all General Electric Company (GE) CF34-8C model turbofan engines. AD 2019-22-05 required initial and repetitive inspections of the operability bleed valve (OBV) fuel tubes, OBV bleed air manifold link rod assemblies, and the OBV fuel fittings. AD 2019- 22-05 also required replacement of OBVs or related OBV link rod hardware that fail inspection. This AD was prompted by multiple reports of fuel leaks, some leading to engine fires, which have occurred as a result of malfunctions related to the OBV. Additionally, the manufacturer has redesigned the OBV, which terminates the need for the repetitive inspections. This AD requires initial and repetitive inspections of the OBV fuel tubes, OBV bleed air manifold link rod assemblies, and the OBV fuel fittings installed on GE CF34-8C model turbofan engines. This AD requires replacement of OBVs or related OBV link rod hardware that fail inspection. As a terminating action to the repetitive inspections, this AD requires replacement of certain OBVs installed on GE CF34-8C model turbofan engines. This AD also requires replacement of certain OBVs installed on GE CF34-8E model turbofan engines. The FAA is issuing this AD to address the unsafe condition on these products.
(1) For CF34-8C1, CF34-8C5, CF34-8C5A1, and CF34-8C5B1 model turbofan engines with serial numbers (S/Ns): 965101 through 965670 inclusive; 194101 through 194999 inclusive; and 195101 through 195653 inclusive:
(i) Within 880 flight hours (FHs) since the previous inspection, 500 FHs after December 23, 2019 (the effective date of AD 2019-22-05), or 6,880 FHs since new, whichever occurs later, inspect the OBV bleed air manifold link rod assemblies, the OBV fuel fittings, and the OBV fuel tubes.
(ii) Thereafter, within every 880 FHs since the previous inspection, perform additional repeat inspections of the OBV bleed air manifold link rod assemblies, the OBV fuel fittings, and the OBV fuel tubes.
(iii) Use the Accomplishment Instructions, paragraph 3.B., of GE CF34-8C Service Bulletin (SB) 75-0020 R04, dated May 10, 2019 (GE SB 75-0020), to perform inspections required by paragraphs (g)(1)(i) and (ii) of this AD and, per the inspection criteria in paragraph 3.B., of GE SB 75-0020 (the inspection criteria), do the following:
(A) Before further flight, if fuel leakage is observed at the OBV fuel fittings or the OBV fuel fittings are loose, replace the OBV with a part eligible for installation.
(B) Before further flight, if any OBV fuel tube clamp is found to be outside the inspection criteria, re-torque the OBV fuel tube clamp or replace the OBV fuel tube clamp.
(C) Within 50 flight cycles (FCs) after the inspections required by paragraphs (g)(1)(i) and (ii) of this AD, replace any link rod hardware found to be outside the inspection criteria. Until the worn link rod hardware is replaced, the OBV fuel fittings must be inspected before the first flight of each day for leakage and looseness in accordance with the inspection criteria. If the OBV fuel fittings fail to meet the inspection criteria, before further flight, replace the OBV and worn link rod hardware.
(2) For CF34-8C5B1 model turbofan engines with S/Ns not listed in paragraph (g)(1) of this AD and for all CF34-8C5A2 and CF34-8C5A3 model turbofan engines, perform the following:
(i) Within 880 FHs after the effective date of this AD or prior to accumulating 6,880 FHs since new, whichever occurs later, perform an initial inspection of the OBV bleed air manifold link rod assemblies, OBV fuel fittings, and OBV fuel tubes.
(ii) Thereafter, within every 880 FHs since the last inspection, repeat the inspection of the OBV bleed air manifold link rod assemblies, OBV fuel fittings, and OBV fuel tubes.
(iii) Use the Accomplishment Instructions, paragraph 3.B., of GE SB 75-0020, to perform the inspections in paragraph (g)(2)(i) and (ii) of this AD and, per the inspection criteria in paragraph 3.B., of GE SB 75-0020, do the following:
(A) Before further flight, if fuel leakage is observed at the OBV fuel fittings or the OBV fuel fittings are loose, replace the OBV with a part eligible for installation.
(B) Before further flight, if any OBV fuel tube clamp is found to be outside the inspection criteria, re-torque the OBV fuel tube clamp or replace the OBV fuel tube clamp.
(C) Within 50 FCs after the inspections required by paragraphs (g)(2)(i) and (ii) of this AD, replace any link rod hardware found to be outside the inspection criteria. Until the worn link rod hardware is replaced, the OBV fuel fittings must be inspected before the first flight of each day for leakage and looseness in accordance with the inspection criteria. If the OBV fuel fittings fail to meet the inspection criteria, before further flight, replace the OBV and worn link rod hardware.
(3) For all affected engines with an installed OBV, VIN 5000728-104 part number (P/N) (P/N 4123T71P02), VIN 5000728-106 (P/N 4123T71P03), or VIN 5080046-101 (P/N 4123T71P04), having an OBV S/N listed in Appendix A, paragraph 4., of GE CF34-8C SB 75-0025 R01, dated August 1, 2019 (GE SB 75-0025), or Appendix A, paragraph 4., of GE CF34-8E SB 75-0019 R01, dated August 1, 2019 (GE SB 75-0019), respectively, within 180 days after the effective date of this AD, remove the OBV and replace with a part eligible for installation.
(4) For all affected engines with an installed OBV, VIN 5000728-104 (P/N 4123T71P02), VIN 5000728-106 (P/N 4123T71P03), or VIN 5080046-101 (P/N 4123T71P04), having an OBV S/N not listed in Appendix A, paragraph 4., of GE SB 75-0025 or Appendix A, paragraph 4., of GE SB 75-0019, respectively, remove the OBV and replace with a part eligible for installation within the following compliance times:
(i) For an OBV that has accumulated more than 25,000 FHs since new as of the effective date of this AD, remove and replace the OBV within 16 months of the effective date of this AD.
(ii) For an OBV that has accumulated between 12,500 to 25,000 FHs since new, inclusive, as of the effective date of this AD, remove and replace the OBV within 32 months of the effective date of this AD.
(iii) For an OBV with fewer than 12,500 FHs since new as of the effective date of this AD, remove and replace the OBV within 48 months of the effective date of this AD.
(5) For all affected engines with an installed OBV, VIN 5080046-102 (P/N 4123T71P05), before the OBV accumulates 25,000 FHs since new or within 10 years of the effective date of this AD, whichever occurs first, remove the OBV and replace with a part eligible for installation.
(6) For all affected engines with an installed OBV, if the accumulated FHs since new of the OBV is unknown, use the FHs since new of the engine.
(7) If the OBV was upgraded or the OBV cap was replaced using the service information identified in paragraph 1., Planning Information, paragraph C., Compliance, of GE CF34-8E SB 75-0021 R00, dated February 21, 2020, the accumulated FHs since the OBV was upgraded or accumulated FHs since the OBV cap was replaced, as applicable, may be used instead of accumulated FHs since new of the OBV.
Installation of an OBV that meets the definition of a part eligible for installation in paragraph (i) of this AD constitutes terminating action for the inspections required by paragraphs (g)(1) and (2) of this AD.
For the purpose of this AD, a “part eligible for installation” is an OBV VIN 5080046-103 (P/N 4123T71P06) or an OBV reworked to VIN 5080046-103 (P/N 4123T71P06).
The reporting instructions specified in GE SB 75-0020 are not required by this AD.
