Transportation Department, Federal Aviation Administration
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.
Document Headings Document headings vary by document type but may contain the following: the agency or agencies that issued and signed a document the number of the CFR title and the number of each part the document amends, proposes to amend, or is directly related to the agency docket number / agency internal file number the RIN which identifies each regulatory action listed in the Unified Agenda of Federal Regulatory and Deregulatory Actions See the Document Drafting Handbook for more details. Department of Transportation Federal Aviation Administration 14 CFR Part 39 [Docket No. FAA-2026-2724; Project Identifier AD-2025-01606-E; Amendment 39-23451; AD 2026-17-08] RIN 2120-AA64 AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: 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. DATES: This AD is effective October 8, 2026. The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of October 8, 2026. ADDRESSES: AD Docket: You may examine the AD docket at regulations.gov under Docket No. FAA-2026-2724; or in person at Docket Operations between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this final rule, any comments received, and other …
Other Federal Register documents from the same docket.
Citation: 91 FR 56578
