Summary
The FAA proposes to adopt a new airworthiness directive (AD) for all General Electric Company (GE) GE90-110B1 and GE90-115B model turbofan engines and certain GE90-76B, GE90-85B, GE90-90B, and GE90-94B model turbofan engines. This proposed AD was prompted by the detection of melt-related freckles in the forgings and billets, which may reduce the life of certain rotating compressor discharge pressure (CDP) high- pressure turbine (HPT) seals (rotating CDP seals), interstage HPT rotor seals, and HPT rotor stage 2 disks. This proposed AD would require revising the airworthiness limitations section (ALS) of the applicable GE90-100 Engine Manual (EM) and the operator's existing approved maintenance program or inspection program, as applicable, to incorporate reduced life limits for these parts. This proposed AD would also require the removal and replacement of certain interstage HPT rotor seals, identified by serial number (S/N), installed on GE90-76B, GE90-85B, GE90-90B, and GE90-94B model turbofan engines. The FAA is proposing this AD to address the unsafe condition on these products.