# Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes
> **Rule** · Final rule. · Published 2021-06-15 · Effective 2021-07-20 · 86 FR 31599
## Document
- **Document number:** 2021-12435
- **Category:** airworthiness
- **Manufacturer:** De Havilland
- **Type:** Rule
- **Action:** Final rule.
- **Citation:** 86 FR 31599
- **Publication date:** 2021-06-15
- **Effective date:** 2021-07-20
- **FAA docket:** Docket No. FAA-2021-0183
## Abstract

The FAA is adopting a new airworthiness directive (AD) for certain De Havilland Aircraft of Canada Limited Model DHC-8-400 series airplanes. This AD was prompted by a report that a number of nacelle A- frames were not manufactured in accordance with engineering drawings. This AD requires, depending on airplane configuration, removing the fasteners on the nacelle A-frame side brace sub-assemblies, doing an eddy current inspection for cracking, cold-working the holes, installing oversize fasteners, re-identifying the reworked side brace fitting and A-frame, and repair if necessary. The FAA is issuing this AD to address the unsafe condition on these products.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2021/06/15/2021-12435/airworthiness-directives-de-havilland-aircraft-of-canada-limited-type-certificate-previously-held-by)
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