Federal Register #FAA20263875

FAA Proposes Airworthiness Directive for GE CF34 Engines Due to Corrosion Risk

The Federal Aviation Administration (FAA) is proposing a new airworthiness directive (AD) targeting corrosion risks in General Electric (GE) CF34 engine models. - Government Buyer: - Federal Aviation Administration (FAA), Department of Transportation - OEMs and Vendors: - General Electric Company (GE) is the primary OEM for the affected engines and components - Products/Services Requested: - Inspection and maintenance actions for 1,152 GE CF34-1A, CF34-3A, CF34-3A1, CF34-3A2, and CF34-3B engines - Specific components include: - HPC (High-Pressure Compressor) Lower Case (Part Numbers: 6040T84P01, 6052T48P01) - HPC Upper Case (Part Numbers: 6040T84P02, 6052T48P02) - Compressor Case Assemblies (Part Numbers: 4922T71G01, 5088T55G01, 5088T55G02, 5088T55G03, 6078T70G01, 6078T70G02, 6078T70G03) - Required services include: - Repetitive engine heat soak restart tests (every 3 months) - Borescope inspections of the HPC case for corrosion - Variable geometry (VG) system functional checks for pressure evaluation - Force gage tests on feedback cables - Visual inspections for obstructions in the VG system - Engine removal from service if necessary - Revision of the engine maintenance manual to include new VG system checks - Unique or Notable Requirements: - Mandatory, recurring inspections and tests to address corrosion-related safety risks - Updates to airworthiness limitations and maintenance manuals - Compliance required for all affected engines on U.S. registry - Detailed inspection and testing protocols must be followed as specified by GE service bulletins and FAA guidance - Place of Performance/Delivery: - FAA offices in Burlington, MA and Des Moines, WA - General Electric Company facility in Cincinnati, OH

Description

The FAA proposes a new airworthiness directive (AD) for certain General Electric Company Model CF34 engines due to corrosion in the high-pressure compressor case affecting the variable geometry system. This corrosion was identified following a dual engine power loss event and manufacturer investigation. The AD requires restart tests, borescope inspections, pressure evaluations, force gage tests, visual inspections, possible engine removal from service, and revisions to the engine maintenance manual. The goal is to detect and address corrosion that could lead to loss of engine thrust control and reduced airplane control.

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