Airworthiness Directives; General Electric Company Turbofan Engines

The FAA is adopting a new airworthiness directive (AD) for all General Electric Company (GE) GE90-110B1 and GE90-115B model turbofan engines with a certain interstage high-pressure turbine (HPT) rotor seal installed. This AD requires initial and repetitive ultrasonic inspections (USIs) of the interstage HPT rotor seal and, depending on the results of the inspection, replacement of the interstage HPT rotor seal with a part eligible for installation. This AD also requires the removal of the interstage HPT rotor seal at the next engine shop visit. This AD was prompted by investigative findings from an event involving an uncontained interstage HPT rotor seal failure that resulted in debris penetrating the fuselage and the other engine. The FAA is issuing this AD to address the unsafe condition on these products.