# Airworthiness Directives; Bell Textron Canada Limited Helicopters
> **Rule** · Final rule; request for comments. · Published 2025-04-10 · Effective 2025-04-25 · 90 FR 15310
## Document
- **Document number:** 2025-06121
- **Category:** airworthiness
- **Manufacturer:** Bell Textron Canada Limited
- **Type:** Rule
- **Action:** Final rule; request for comments.
- **Citation:** 90 FR 15310
- **Publication date:** 2025-04-10
- **Effective date:** 2025-04-25
- **FAA docket:** Docket No. FAA-2025-0486
## Abstract

The FAA is adopting a new airworthiness directive (AD) for certain Bell Textron Canada Limited (Bell) Model 505 helicopters. The FAA previously sent this AD as an emergency AD to all known U.S. owners and operators of these helicopters. This AD was prompted by deformation and/or improper pin engagement in the knuckles of the door hinge on the aft movable ballast box assembly. This AD requires removing all ballast weights from the aft movable ballast box assembly and prohibits the use of ballast weights within the aft movable ballast box assembly, as specified in a Transport Canada emergency AD, which is incorporated by reference. The FAA is issuing this AD to address the unsafe condition on these products.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2025/04/10/2025-06121/airworthiness-directives-bell-textron-canada-limited-helicopters)
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