EASA AD US-2021-26-19
Engine - High Pressure Turbine Rotor Stage 1 Disk - Replacement
Summary
The Federal Aviation Administration's Airworthiness Directive 2021-26-19 addresses certain General Electric Company CF34-8C and CF34-8E model turbofan engines. It requires the removal and replacement of the high-pressure turbine (HPT) rotor stage 1 disk, part number 4125T22P04, due to a manufacturing quality escape that could lead to disk failure. This directive applies to engines with specific serial numbers and aims to ensure continued airworthiness and safety.
What Changed
This new airworthiness directive introduces a mandatory requirement to remove and replace affected HPT rotor stage 1 disks before they accumulate 7,600 cycles or at the next engine shop visit, whichever occurs first. It also provides definitions for engine shop visits and eligible parts, and references GE service bulletins and repair documents for compliance. No previous directives are superseded by this AD.
Why It Matters
This directive is critical for aviation professionals because the affected HPT rotor stage 1 disks may have tool gouges that reduce their life, posing a risk of uncontained disk release and potential damage to the engine and aircraft. Operators and maintenance organizations must ensure timely compliance to prevent unsafe conditions and maintain regulatory compliance. The AD also clarifies repair eligibility, aiding maintenance planning and parts management.
What To Do
Operators must remove and replace the affected HPT rotor stage 1 disks at the next engine shop visit or before the disk reaches 7,600 cycles since new, whichever occurs first after January 25, 2022. Only parts not listed in the AD or those repaired with FAA-approved procedures are eligible for installation. Requests for alternative methods of compliance can be submitted to the FAA's ECO Branch following established procedures.
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