EASA AD US-2020-21-13
Engine - High-Pressure Turbine Rotor Stage 2 Disks and Rotating Compressor Discharge Pressure Seals - Replacement
Summary
The Federal Aviation Administration's Airworthiness Directive 2020-21-13 addresses certain General Electric Company GE90-110B1 and GE90-115B turbofan engines. It mandates replacement of specific high-pressure turbine rotor stage 2 disks and rotating compressor discharge pressure seals due to detected melt-related freckles that may reduce their life limits. This directive aims to prevent unsafe conditions that could lead to engine and aircraft damage.
What Changed
This new airworthiness directive introduces mandatory replacement requirements for affected HPT rotor stage 2 disks and rotating CDP HPT seals identified by specific part and serial numbers. It establishes compliance timelines based on cycles since new or at the next engine shop visit, whichever occurs first. The directive also clarifies definitions and provides procedures for alternative methods of compliance.
Why It Matters
This directive is critical for aviation professionals as it addresses a potential unsafe condition that could cause uncontained engine part failure, risking aircraft safety. Operators and maintenance organizations must ensure timely replacement of affected parts to maintain airworthiness and comply with FAA regulations. Compliance helps avoid costly in-service failures and supports continued safe operation of aircraft equipped with these GE90 engine models.
What To Do
Operators with GE90-110B1 and GE90-115B engines must identify if their engines have the affected HPT rotor stage 2 disks or rotating CDP HPT seals by part and serial number. They must replace these parts before exceeding specified cycles since new or at the next engine shop visit, whichever occurs first, or immediately if the threshold has already been exceeded. Requests for alternative compliance methods can be submitted to the FAA following established procedures.
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