# Airworthiness Directives; De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes
> **Rule** · Final rule. · Published 2023-03-14 · Effective 2023-04-18 · 88 FR 15609
## Document
- **Document number:** 2023-05060
- **Category:** airworthiness
- **Manufacturer:** De Havilland
- **Type:** Rule
- **Action:** Final rule.
- **Citation:** 88 FR 15609
- **Publication date:** 2023-03-14
- **Effective date:** 2023-04-18
- **FAA docket:** Docket No. FAA-2022-1653
## 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 reports of flap power unit (FPU) pressure switch failures resulting in flap inoperative events. This AD requires replacing the FPU or replacing the FPU pressure switch and reidentifying the FPU. This AD also prohibits the installation of affected parts. The FAA is issuing this AD to address the unsafe condition on these products.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2023/03/14/2023-05060/airworthiness-directives-de-havilland-aircraft-of-canada-limited-type-certificate-previously-held-by)
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