Airworthiness Directives; General Electric Company Turbofan Engines

We are adopting a new airworthiness directive (AD) for certain General Electric Company model GEnx-2B67 and GEnx-2B67B turbofan engines. This AD was prompted by the original equipment manufacturer's disclosure that certain critical rotating life-limited parts (LLPs) used in Boeing 747-8 flight tests had consumed more cyclic life than they would have in revenue flight cycles. These parts were then installed into engines and introduced into revenue service without adjustment to remaining cyclic life. This AD requires a one-time adjustment to the cycle counts of those LLPs to account for the additional low cycle fatigue (LCF) life consumed during flight tests. We are issuing this AD to prevent the failure of critical rotating LLPs, uncontained engine failure, and damage to the airplane.