AD 2019-16-04 Airworthiness Directives; Engine Alliance Turbofan Engines

This AD applies to all Engine Alliance (EA) GP7270 and GP7277 model turbofan engines.

Comply with this AD within the compliance times specified, unless already done.

(1) For EA GP7270 and GP7277 model turbofan engines, with engine fan hub assembly part numbers (P/Ns) 5760221 or 5760321, and with serial numbered engine fan hub assemblies identified in Planning Information, Table 4, in EA Alert Service Bulletin (ASB) EAGP7-A72-389, Revision No. 4, dated June 14, 2019, within 3,000 cycles since new, or before further flight after the effective date of this AD, whichever occurs later: (i) For engine fan hub assemblies at the low-pressure compressor (LPC) module assembly level: (A) Perform a visual inspection of the engine fan hub assembly, in accordance with the Accomplishment Instructions, For Fan Hubs at LPC Module Assembly Level, paragraphs 1.A.(1), 1.A.(4), and 1.A.(6)(a), of EA ASB EAGP7-A72-389, Revision No. 4, dated June 14, 2019. (B) Perform an eddy current inspection (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 2.A and 2.B, of EA ASB EAGP7-A72-389, Revision No. 4, dated June 14, 2019. (ii) For engine fan hub assemblies at the piece part level: (A) Perform a visual inspection of the engine fan hub assembly, in accordance with the Accomplishment Instructions, For Fan Hubs at Piece Part Level, paragraphs 1.A.(1) and 1.A.(3), of EA ASB EAGP7-A72-389, Revision No. 4, dated June 14, 2019. (B) 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 2.A and 2.B, of EA ASB EAGP7-A72-389, Revision No. 4, dated June 14, 2019. (iii) For engine fan hub assemblies installed in an engine (on-wing or off-wing): (A) Perform a visual inspection of the engine fan hub assembly, in accordance with the Accomplishment Instructions, For Fan Hubs Installed in an Engine, paragraphs 1.C.(1), 1.C.(5), and 1.C.(7)(a), of EA ASB EAGP7-A72-389, Revision No. 4, dated June 14, 2019. (B) 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 1.D.(1) and 1.D.(2), of EA ASB EAGP7-A72-389, Revision No. 4, dated June 14, 2019. (iv) If the engine fan hub assembly visual inspection reveals defects or damage to the engine fan hub assembly outside the serviceable limits specified in Table 6 in the Accomplishment Instructions of EA ASB EAGP7-A72-389, Revision No. 4, dated June 14, 2019, before further flight, remove the engine fan hub assembly from service and replace with a part eligible for installation. (v) If the engine fan hub assembly ECI results in a rejectable indication per the Appendix, Added Data, of EA ASB EAGP7-A72-389, Revision No. 4, dated June 14, 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 inspections as required by paragraph (g)(2)(i), (g)(2)(ii), and (g)(2)(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), (g)(2)(ii), and (g)(2)(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 as the result of the inspections required by (g)(2)(i), (g)(2)(ii), or (g)(2)(iii) of this AD, before further flight, remove the engine fan hub assembly from service and replace 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.

This AD was prompted by an uncontained failure of the engine fan hub. The FAA is issuing this AD to detect defects, damage, and cracks that could result in an uncontained failure of the engine fan hub assembly. The unsafe condition, if not addressed, could result in uncontained failure of the engine fan hub assembly, damage to the engine, and damage to the airplane.

This AD replaces AD 2019-03-04, Amendment 39-19556 (84 FR 4694, February 19, 2019).