# Airworthiness Directives; Bombardier, Inc. Airplanes
> **Rule** · Final rule; request for comments. · Published 2019-08-08 · Effective 2019-08-23 · 84 FR 38862
## Document
- **Document number:** 2019-16811
- **Category:** airworthiness
- **Type:** Rule
- **Action:** Final rule; request for comments.
- **Citation:** 84 FR 38862
- **Publication date:** 2019-08-08
- **Effective date:** 2019-08-23
- **FAA docket:** Docket No. FAA-2019-0578
## 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 of a mis-installed no-back pawl discovered on a horizontal stabilizer trim actuator (HSTA). This AD requires an inspection to verify the horizontal stabilizer trim electronic control unit (HSTECU) part number, a software upgrade for certain HSTECUs, and installation of HSTECUs with upgraded software. The FAA is issuing this AD to address the unsafe condition on these products.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2019/08/08/2019-16811/airworthiness-directives-bombardier-inc-airplanes)
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