Federal Register #FAA20268803

FAA Proposed Airworthiness Directive for CFM International CFM56 Engines

This opportunity involves a proposed airworthiness directive from the Federal Aviation Administration (FAA) targeting specific CFM International CFM56 engine models due to safety concerns. - Government Buyer: - Federal Aviation Administration (FAA) - Aircraft Certification Service, Continued Operational Safety Branch - OEM Highlight: - CFM International, S.A. is the sole Original Equipment Manufacturer (OEM) referenced - Products/Parts Requested: - High-pressure turbine (HPT) inner stationary seal (P/N 1808M56G01) - HPT front seal (P/N 1795M36P01, 1795M36P02) - HPT rotor blades (no specific part number) - No. 3 ball bearing (no specific part number) - Services/Inspections Required: - Initial and repetitive borescope inspections of HPT front seal for cracks - Inspection of HPT inner stationary seal for honeycomb separation - Removal and replacement of affected HPT inner stationary seal - Removal and replacement of HPT front seal, rotor blades, and No. 3 ball bearing if necessary - Notable Requirements: - Compliance actions are based on inspection findings, not fixed quantities - Estimated 39 engines affected in the U.S. registry - Directive prompted by honeycomb separation issues that could lead to engine damage and uncontained part release - Incorporates guidance from the European Union Aviation Safety Agency (EASA) - No specific purchase quantities for parts; actions are performed as needed based on inspection results

Description

The FAA proposes a new airworthiness directive (AD) for certain CFM International Model CFM56-5B, CFM56-5C, and CFM56-7B engines with a specific high-pressure turbine (HPT) inner stationary seal installed. This AD is prompted by reports of honeycomb separation from the HPT inner stationary seals. It requires initial and repetitive borescope inspections of the HPT front seal for cracks and, depending on findings, replacement with an eligible part. The AD also mandates removal and replacement of the affected HPT inner stationary seal, inspection for honeycomb separation, and if necessary, removal and replacement of the HPT front seal, rotor blades, and No. 3 ball bearing to address unsafe conditions.

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