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AD 2025-22623

Published 2025-12-12 · 4 models · 28 US-registered tails affected · Federal Register

Airworthiness Directives; Bell Textron Canada Limited Helicopters Federal Register ↗

Abstract

The FAA is adopting a new airworthiness directive (AD) for certain Bell Textron Canada Limited (Bell) Model 427 helicopters. This AD was prompted by a report of a cracked transmission oil check valve (check valve). This AD requires inspecting and measuring certain check valves and, depending on the results, repetitively inspecting and removing the check valve from service if it has leaks or is cracked. This AD also prohibits installing the affected check valves on any helicopter. The FAA is issuing this AD to address the unsafe condition on these products.

Applicability · by US fleet size

Federal Register text

Verbatim; the Federal Register publication is the legally binding document. Cite: 90 FR 57678. View on Federal Register ↗

[Federal Register Volume 90, Number 237 (Friday, December 12, 2025)] [Rules and Regulations] [Pages 57678-57680] From the Federal Register Online via the Government Publishing Office [www.gpo.gov] [FR Doc No: 2025-22623]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2025-1727; Project Identifier MCAI-2024-00750-R; Amendment 39-23209; AD 2025-25-01] RIN 2120-AA64

Airworthiness Directives; Bell Textron Canada Limited Helicopters

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for certain Bell Textron Canada Limited (Bell) Model 427 helicopters. This AD was prompted by a report of a cracked transmission oil check valve (check valve). This AD requires inspecting and measuring certain check valves and, depending on the results, repetitively inspecting and removing the check valve from service if it has leaks or is cracked. This AD also prohibits installing the affected check valves on any helicopter. The FAA is issuing this AD to address the unsafe condition on these products.

DATES: This AD is effective January 16, 2026. The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of January 16, 2026.