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Airworthiness Directive

AD 2025-25-01 90 FR 57678 Active

Federal Aviation Administration · 14 CFR part 39

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.

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FR document
2025-22623
Amendment
39-23209
Published
2025-12-12
Effective
2026-01-16
Models covered
1

Last live check: 2026-08-19

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AD

2025-25-01

FR doc 2025-22623 · 90 FR 57678

AD 2025-25-01Published 2025-12-12Effective 2026-01-16

FAA rule - 14 CFR 39

FAA rule. Compliance with an applicable AD is required under 14 CFR 39.7. Check its effective date, applicability, compliance times and current status.

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.

Full official 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.

More directives for Bell 427

  1. AD 2025-13-01 Airworthiness Directives; Bell Textron Canada Limited Helicopters Effective 2025-07-08
  2. AD 2021-19-01 Airworthiness Directives; Bell Textron Canada Limited Helicopters Effective 2021-10-13
  3. AD 2019-23-09 Airworthiness Directives; Bell Helicopter Textron Canada Limited Helicop... Effective 2020-01-10
  4. AD 2016-20-01 Airworthiness Directives; Bell Helicopter Textron Canada Limited (Bell) ... Effective 2016-10-17
  5. AD 2015-17-02 Airworthiness Directives; Bell Helicopter Textron Canada (Bell) Helicopt... Effective 2015-09-24

All Bell 427 directives

View on Federal Register (opens in a new tab) View this AD in FAA DRS (opens in a new tab) Print AD packet (opens the full Federal Register document in a new tab)

Applies to 1 model in our index