AD 2020-10-04: Event Involving An Uncontained Interstage HPT Rotor Seal Failure

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 highpressure 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.

DATES: This AD is effective May 27, 2020.

SUPPLEMENTARY INFORMATION: The FAA received a report of an event that occurred on October 20, 2019, in which a Boeing Model 777-300ER airplane, powered by GE GE90-115B model turbofan engines, experienced an uncontained interstage HPT rotor seal failure resulting in an aborted takeoff. The FAA has determined that an unusual flight profile is a contributing factor in the failure of the interstage HPT rotor seal. This condition, if not addressed, could result in an uncontained interstage HPT rotor seal release, release of high-energy debris, damage to the engine, and damage to the airplane. The FAA is issuing this AD to address the unsafe condition on these products.

FMI: www.regulations.gov