Summary
The Federal Aviation Administration (FAA) proposes to adopt a new airworthiness directive (AD) that is applicable to General Electric Company (GE) GE90 series turbofan engines. This proposal would require removing from service high pressure turbine (HPT) interstage seals, identified by GE as the pre-life-improved rotor (pre-LIR) configuration, and installing a new design, identified by GE as the life improved rotor (LIR) configuration seal. This proposal would also require a new lower life limit for the LIR configuration seal. This proposal is prompted by an uncontained engine failure which occurred during a factory development engine ground test. The actions specified by the proposed AD are intended to prevent failure of the HPT interstage seal that could result in an uncontained engine failure and damage to the airplane.