Airworthiness Directive · Amendment 39-19735 · Turbine engine compressor section
Engine Alliance Turbofan Engines
Superseded. A later AD replaced this one: AD 2021-26-04. Comply with the one in force.
This AD applies to all Engine Alliance (EA) GP7270 and GP7277 model turbofan engines.
The FAA is superseding Airworthiness Directive (AD) 2019-16-04 for all Engine Alliance (EA) GP7270 and GP7277 model turbofan engines. AD 2019-16-04 required a visual inspection of the 1st-stage low- pressure compressor (LPC) rotor assembly, referred to after this as the "engine fan hub assembly," for damage, a one-time eddy current inspection (ECI) of the engine fan hub blade slot bottom and blade slot front edge for cracks; and removal of parts if damage or defects are found. AD 2019-16-04 also required replacement of the engine fan hub blade lock assembly for certain GP7270 and GP7277 model turbofan engines. This AD, for certain GP7270 and GP7277 model turbofan engines, reduces the compliance time for the initial ECI and requires repetitive ECIs of the engine fan hub blade slot bottom and blade slot front edge for cracks. This AD also retains the visual inspection requirements of the engine fan hub assembly for all GP7270 and GP7277 model turbofan engines. This AD was prompted by an uncontained failure of the engine fan hub. The FAA is issuing this AD to address the unsafe condition on these products.
(1) For EA GP7270 and GP7277 model turbofan engines with engine fan hub assembly part numbers (P/Ns) 5760221 or 5760321, within 1,700 cycles since new, or within 150 flight cycles (FCs) after the effective date of this AD, or within 330 FCs since an eddy current inspection (ECI) was performed in accordance with the Accomplishment Instructions, For Fan Hubs at LPC Module Assembly Level, paragraphs 2.A and 2.B, of EA ASB EAGP7-A72-389, Revision No. 4, dated June 14, 2019, or earlier versions of that ASB; or within 330 FCs since overhaul, whichever occurs later:
(i) For engine fan hub assemblies at the low-pressure compressor (LPC) module assembly level, perform an ECI of the engine fan hub blade slot bottoms and front edges in accordance with the Accomplishment Instructions, For Fan Hubs at LPC Module Assembly Level, paragraphs 1.B. and 1.C., of EA ASB EAGP7-A72-389, Revision No. 5, dated August 23, 2019.
(ii) For engine fan hub assemblies at the piece part level, perform an ECI of the engine fan hub blade slot bottoms and front edges, in accordance with the Accomplishment Instructions, For Fan Hubs at Piece Part Level, paragraphs 1.A. and 1.B., of EA ASB EAGP7-A72-389, Revision No. 5, dated August 23, 2019.
(iii) For engine fan hub assemblies installed in an engine (on-wing or off-wing), perform an ECI of the engine fan hub blade slot bottoms and front edges, in accordance with the Accomplishment Instructions, For Fan Hubs Installed in an Engine, paragraphs 3.B. and 3.C., of EA ASB EAGP7-A72-389, Revision No. 5, dated August 23, 2019.
(iv) Thereafter, repeat the ECI of the engine fan hub blade slot bottoms and front edges at intervals not exceeding 330 FCs since the previous ECI required by paragraphs (g)(1)(i) through (iii) of this AD, as applicable.
(v) If any ECI of the engine fan hub assembly results in a rejectable indication per the Appendix, Added Data, of EA ASB EAGP7-A72-389, Revision No. 5, dated August 23, 2019, remove the engine fan hub assembly from service and, before further flight, replace with a part that is eligible for installation.
(2) For all GP7270 and GP7277 model turbofan engines, after the effective date of this AD:
(i) At the next disassembly of the engine fan hub blade lock assembly, visually inspect the following areas for damage:
(A) The fan hub blade lock retention hooks (also known as lock ring contact area); and
(B) The fan hub rim face.
(ii) At the next reassembly of the fan hub blade lock assembly, visually inspect the following areas of the engine fan hub for damage:
(A) The fan hub scallop areas;
(B) The fan hub bore area behind the balance flange;
(C) The fan hub fan blade lock retention hooks;
(D) The fan hub rim face; and
(E) The clinch nut holes.
(iii) After any reassembly per paragraph (g)(2)(ii), before further flight, perform an independent inspection of all areas of the engine fan hub referenced in paragraph (g)(2)(ii) of this AD for damage.
(iv) Thereafter, repeat the inspections required by paragraphs (g)(2)(i) through (iii) of this AD at each disassembly and reassembly of the engine fan hub blade lock assembly.
(v) As an optional terminating action to the inspection requirements and independent inspection requirements of paragraph (g)(2)(i) through (iii) of this AD, insert the requirements for the visual inspections and independent inspections required by these paragraphs as Required Inspection Items in the approved continuous airworthiness maintenance program for the airplane.
(vi) If damage is found outside serviceable limits during the inspections required by (g)(2)(i) through (iii) of this AD, before further flight, remove the engine fan hub assembly from service and replace it with a part eligible for installation.
(3) For GP7270 and GP7277 model turbofan engines with engine serial numbers P550101 through P550706, remove the engine fan hub blade lock assembly, P/N 5700451, by September 1, 2020, and replace with a part eligible for installation. Refer to EA ASB EAGP7-A72-418, Revision No. 1, dated January 11, 2019, for guidance on replacement of the engine fan hub blade lock assembly.
