Airworthiness Directive · Amendment 39-21714 · Turbine engine combustion section
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 with an outer shell combustion liner (combustion outer liner shell), part number (P/N) 4124T04G04, P/N 4124T04G05, or P/N 5159T35G02, installed.
The FAA is adopting a new airworthiness directive (AD) for all General Electric Company (GE) CF34-8 model turbofan engines with a certain outer shell combustion liner (combustion outer liner shell) installed. This AD was prompted by two in-flight engine shutdowns (IFSDs) that occurred as a result of failures of the combustion outer liner shell. This AD requires a borescope inspection (BSI) or visual inspection of the combustion outer liner shell and, depending on the results of the inspection, possible replacement of the combustion outer liner shell. The FAA is issuing this AD to address the unsafe condition on these products.
(1) For an affected engine with a combustion outer liner shell that on the effective date of this AD has accumulated 17,500 flight hours (FHs) or greater time since new (TSN), or time since repair (TSR), perform an initial borescope inspection (BSI) or visual inspection of the combustion outer liner shell for cracks before accumulating 500 engine FHs after the effective date of this AD.
(i) For GE CF34-8C engines, inspect using the Accomplishment Instructions, paragraphs 3.A.(4) and 3.A.(5), of GE CF34-8C Alert Service Bulletin (SB) 72-A0335 R02, dated February 25, 2020 (CF34-8C Alert SB 72-A0335).
(ii) For GE CF34-8E engines, inspect using the Accomplishment Instructions, paragraphs 3.A.(4) and 3.A.(5), of GE CF34-8E Alert SB 72-A0221 R02, dated February 25, 2020 (CF34-8E Alert SB 72-A0221).
Note 1 to paragraph (g)(1): GE has identified the service information as an “Alert Service Bulletin,” which is stated only in the body of the Alert SB.
(2) For an affected engine with a combustion outer liner shell that on the effective date of this AD has accumulated 17,499 FHs or fewer TSN or TSR, before accumulating 500 engine FHs after the combustion outer liner shell has accumulated 17,500 FHs TSN or TSR, perform an initial BSI or visual inspection on the combustion outer liner shell for cracks.
(i) For GE CF34-8C engines, inspect using the Accomplishment Instructions, paragraphs 3.A.(4) and 3.A.(5), of CF34-8C Alert SB 72-A0335.
(ii) For GE CF34-8E engines, inspect using the Accomplishment Instructions paragraphs 3.A.(4) and 3.A.(5), of CF34-8E Alert SB 72-A0221.
(3) For an affected engine with a combustion outer liner shell for which it is not possible to determine the TSN or TSR, use the engine FHs since new to determine when to perform the initial BSI or visual inspection.
(4) After the effective date of this AD, and after the initial inspection required by paragraph (g)(1) or (2) of this AD, re-inspect or remove the combustion outer liner shell using inspection criteria as follows:
(i) For GE CF34-8C engines, use Table 1 of CF34-8C Alert SB 72-A0335.
(ii) For GE CF34-8E engines, use Table 1 of CF34-8E Alert SB 72-A0221.
After the effective date of this AD, do not install a combustion outer liner shell with greater than 17,500 FHs TSN or TSR without first inspecting the combustion outer liner shell in accordance with paragraph (g)(1) of this AD.
For the purpose of this AD, “time since repair (TSR)” is the amount of FHs accumulated on the combustion outer liner shell since performing GEK 105091 or GEK 112031, 72-44-06, REPAIR 023.
