EASA AD US-2026-17-08
Turbine - High-Pressure Compressor Drum Rotor Disk - Inspection / Replacement
Summary
The Federal Aviation Administration Airworthiness Directive 2026-17-08 is a final rule addressing certain Pratt & Whitney Division engines, specifically models PW4074D, PW4077D, PW4084D, PW4090, and PW4090-3. It mandates inspections and possible replacement of high-pressure compressor (HPC) drum rotor disk assemblies due to incorrect shot peening discovered on some parts. This directive aims to ensure continued airworthiness and safety of affected turbine engines.
What Changed
This new airworthiness directive introduces mandatory visual inspections of the HPC drum rotor disk assemblies for incorrect shot peen coverage and requires replacement of affected parts before reaching revised reduced life limits. It also clarifies eligibility criteria for parts after inspection and specifies compliance procedures without incorporating certain service bulletins by reference.
Why It Matters
This directive is critical for aviation professionals because incorrect shot peening can reduce the life of HPC drum rotor disk assemblies, potentially leading to unsafe engine operation. Operators and maintenance organizations must comply to prevent in-service failures, maintain regulatory compliance, and ensure aircraft safety. Understanding the inspection and replacement requirements helps avoid unexpected downtime and costly repairs.
What To Do
Operators of aircraft with affected Pratt & Whitney engines must visually inspect HPC drum rotor disk assemblies for improper shot peening before reaching between 8,600 and 10,400 total life cycles, depending on the part. If defects are found, the affected parts must be replaced with eligible components. All replacements and inspections must be completed by October 8, 2026, the effective date of the directive.
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