Airworthiness Directive · Amendment 39-19480 · Turbine engine compressor section
Engine Alliance Turbofan Engines
Superseded. A later AD replaced this one: AD 2019-15-06. Comply with the one in force.
This AD applies to all Engine Alliance (EA) GP7270, GP7272, and GP7277 model turbofan engines.
We are adopting a new airworthiness directive (AD) for all Engine Alliance (EA) GP7270, GP7272, and GP7277 model turbofan engines. This AD requires inspection of the stage 6 seal ring for correct installation and inspection of the high-pressure compressor (HPC) stages 2-5 spool for cracks. This AD also requires replacement of the HPC stages 2-5 spool if the stage 6 seal ring is incorrectly installed or if the HPC stages 2-5 spool is found cracked. This AD was prompted by a shop finding of axial cracks in the interstage 5-6 seal teeth of the HPC stages 2-5 spool spacer arm, due to an incorrectly installed stage 6 seal ring. We are issuing this AD to address the unsafe condition on these products.
(1) Borescope inspect the stage 6 seal ring location in accordance with the Accomplishment Instructions, paragraph 1.F, in EA Alert Service Bulletin (ASB) EAGP7-A72-395, Revision No. 2, dated August 2, 2018, and within the compliance times specified in Table 1 to paragraph (g) of this AD. If the stage 6 seal ring is incorrectly installed, remove the HPC stages 2-5 spool from service within 50 cycles and replace with a part eligible for installation.
(2) Borescope inspect the interstage 5-6 seal tooth aft face and interstage 5-6 forward face for cracks and missing coating in accordance with the Accomplishment Instructions, paragraphs 2.C and 2.E, in EA ASB EAGP7-A72-395, Revision No. 2, dated August 2, 2018, and within the compliance times specified in Table 1 to paragraph (g) of this AD.
(i) If coating is missing on the interstage 5-6 seal tooth forward or aft faces, repeat the borescope inspection required by paragraph (g)(2) of this AD for cracks every 150 cycles.
(ii) If cracks are found in the interstage 5-6 seal tooth forward or aft faces, remove the HPC stages 2-5 spool from service and replace with a part eligible for installation before further flight.
