# Airworthiness Directives; Bombardier, Inc., Airplanes
> **Rule** · Final rule. · Published 2021-05-19 · Effective 2021-06-23 · 86 FR 27028
## Document
- **Document number:** 2021-10467
- **Category:** airworthiness
- **Type:** Rule
- **Action:** Final rule.
- **Citation:** 86 FR 27028
- **Publication date:** 2021-05-19
- **Effective date:** 2021-06-23
- **FAA docket:** Docket No. FAA-2021-0101
## Abstract

The FAA is adopting a new airworthiness directive (AD) for certain Bombardier, Inc., Model BD-100-1A10 airplanes. This AD was prompted by a report that the inboard multi-function spoiler (MFS) surfaces failed to deploy, which was caused by missing notches on the piston seal of the MFS power control units (PCUs). This AD requires an inspection to determine if affected MFS PCUs are installed, and replacement of affected MFS PCUs. The FAA is issuing this AD to address the unsafe condition on these products.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2021/05/19/2021-10467/airworthiness-directives-bombardier-inc-airplanes)
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