# Airworthiness Directives; Airbus Canada Limited Partnership (Type Certificate Previously Held by C Series Aircraft Limited Partnership (CSALP); Bombardier, Inc.) Airplanes
> **Rule** · Final rule. · Published 2026-05-27 · Effective 2026-07-01 · 91 FR 31341
## Document
- **Document number:** 2026-10486
- **Category:** airworthiness
- **Manufacturer:** Airbus Canada Limited Partnership (Type Certificate Previously Held by C Series
- **Type:** Rule
- **Action:** Final rule.
- **Citation:** 91 FR 31341
- **Publication date:** 2026-05-27
- **Effective date:** 2026-07-01
- **FAA docket:** Docket No. FAA-2025-2543
## Abstract

The FAA is adopting a new airworthiness directive (AD) for certain Airbus Canada Limited Partnership Model BD-500-1A10 and BD-500- 1A11 airplanes. This AD was prompted by the discovery that titanium fasteners had been incorrectly installed in the butt strap at the outer wing box lower skin to center wing box interface in lieu of the correct nickel alloy fasteners. This AD requires the identification of fasteners installed in the butt strap at the outer wing box lower skin to center wing box interface, and applicable on-condition actions. The FAA is issuing this AD to address the unsafe condition on these products.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2026/05/27/2026-10486/airworthiness-directives-airbus-canada-limited-partnership-type-certificate-previously-held-by-c)
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