EASA AD US-2020-10-04
Engine - Interstage High-Pressure Turbine Rotor Seal - Inspection / Replacement
Summary
The document titled "Engine - Interstage High-Pressure Turbine Rotor Seal - Inspection / Replacement" is a Federal Aviation Administration (FAA) Airworthiness Directive (AD 2020-10-04) addressing General Electric Company GE90-110B1 and GE90-115B turbofan engines. It mandates inspections and potential replacement of the interstage high-pressure turbine (HPT) rotor seal to prevent unsafe conditions. The directive applies specifically to these engine models installed on Boeing 777-300ER aircraft.
What Changed
This new AD introduces requirements for initial and repetitive ultrasonic inspections of the interstage HPT rotor seal on affected GE90 engines. Depending on inspection results, it requires replacement of the rotor seal with an eligible part and mandates removal of the seal at the next engine shop visit. The AD is issued as an interim action following an uncontained rotor seal failure event.
Why It Matters
This AD is critical for aviation professionals because it addresses a safety risk involving potential uncontained rotor seal failure, which can cause high-energy debris release and damage to the aircraft and engines. Operators and maintenance organizations must comply to ensure continued airworthiness and prevent in-flight failures. Compliance helps mitigate risks associated with unusual flight profiles that contributed to the failure.
What To Do
Affected operators must perform initial and repetitive ultrasonic inspections of the interstage HPT rotor seal as specified in the AD. If inspection findings indicate, they must replace the seal with a part eligible for installation. Additionally, the seal must be removed at the next engine shop visit. The AD became effective on May 27, 2020, and comments were invited until June 26, 2020.
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