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2026-18019·DEPARTMENT OF TRANSPORTATION

Airworthiness Directives; Pratt & Whitney Division Engines

Final RuleFinal Rule
Published
Sep 3, 2026
Effective
Oct 8, 2026
Citation
91 FR 56578
Docket
Docket No. FAA-2026-2724, Project Identifier AD-2025-01606-E, Amendment 39-23451
Agencies
DEPARTMENT OF TRANSPORTATION, Federal Aviation Administration

Final rule.

Summary

The Federal Aviation Administration (FAA) has issued a final airworthiness directive that requires owners and operators of certain Pratt & Whitney aircraft engines to check a key compressor component for a manufacturing defect. The directive was prompted by the discovery that some high‑pressure compressor drum rotor disk assemblies were not properly shot‑peened—a process that helps prevent cracks. To prevent possible engine failure, the rule mandates a visual inspection of the affected assemblies and, if the inspection shows improper coverage, replacement with an approved part. It also sets a deadline for swapping out any remaining suspect assemblies before they reach specific service‑life limits. The rule applies to Pratt & Whitney Division models PW4074D, PW4077D, PW4084D, PW4090, and PW4090‑3. The FAA, the transportation‑safety agency that oversees civil aviation in the United States, is the issuing authority. The directive is binding on all U.S. airlines, charter operators, and maintenance organizations that use these engine models. The directive was published in the Federal Register on September 3, 2026 and becomes effective on October 8, 2026. Because it is a final rule, there is no additional public comment period; the FAA will now enforce the inspection and replacement requirements. Operators must schedule the required inspections promptly and ensure any non‑conforming parts are removed and replaced before the specified service‑life thresholds are reached.

AI-generated summary — verify against the Federal Register text.

Official abstract

The FAA is adopting a new airworthiness directive (AD) for certain Pratt & Whitney Division (PW) Model PW4074D, PW4077D, PW4084D, PW4090, and PW4090-3 engines. This AD was prompted by the discovery of a quality escape involving incorrect shot peening on certain high- pressure compressor (HPC) drum rotor disk assemblies. This AD requires visually inspecting the HPC drum rotor disk assembly for incorrect shot peen coverage and, depending on the results of the inspection, replacing the HPC drum rotor disk assembly with a part eligible for installation. This AD also requires removing and replacing certain HPC drum rotor disk assemblies before reaching certain life limits. The FAA is issuing this AD to address the unsafe condition on these products.

Topics

Infrastructure

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