Federal Register #2026-18019

FAA Directive: Inspection and Replacement of Pratt & Whitney HPC Drum Rotor Disk Assemblies

The Federal Aviation Administration (FAA), under the Department of Transportation, has issued an airworthiness directive targeting Pratt & Whitney Division Model PW4074D, PW4077D, PW4084D, PW4090, and PW4090-3 engines. - Government Buyer: - Federal Aviation Administration (FAA) - OEM Highlight: - Pratt & Whitney Division is the sole OEM referenced - Products/Services Requested: - Visual inspection of high-pressure compressor (HPC) drum rotor disk assemblies for incorrect shot peen coverage - Replacement of affected HPC drum rotor disk assemblies if incorrect shot peening is found or before reaching specified life limits - Specific part number: 50S634 - Affected serial numbers: CENCD26931, CENCD29577, CENCD29597, CENCD41851, CENCD43536, CENCD30975, CENCD42978 - Inspection procedures per Pratt & Whitney Alert Service Bulletin PW4G112A72373 - Unique Requirements: - Addresses a manufacturing quality escape involving incorrect shot peening - Mandates both inspection and replacement actions based on part life cycles and inspection results - Only assemblies with specific part and serial numbers are affected - No other OEMs or vendors are referenced

Description

The FAA is adopting a new airworthiness directive (AD) for certain Pratt & Whitney Division Model PW4074D, PW4077D, PW4084D, PW4090, and PW4090-3 engines. This AD addresses a quality escape involving incorrect shot peening on certain high-pressure compressor (HPC) drum rotor disk assemblies. It requires a visual inspection of the HPC drum rotor disk assembly for incorrect shot peen coverage and, if necessary, replacement with a part eligible for installation. Additionally, it mandates removing and replacing certain HPC drum rotor disk assemblies before reaching specified life limits to prevent failure and ensure safety.

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