# Airworthiness Directives; Bombardier, Inc., Airplanes
> **Rule** · Final rule. · Published 2018-10-24 · Effective 2018-11-28 · 83 FR 53563
## Document
- **Document number:** 2018-23031
- **Category:** airworthiness
- **Type:** Rule
- **Action:** Final rule.
- **Citation:** 83 FR 53563
- **Publication date:** 2018-10-24
- **Effective date:** 2018-11-28
- **FAA docket:** Docket No. FAA-2018-0160
## Abstract

We are superseding Airworthiness Directive (AD) 2016-24-03, which applied to certain Bombardier, Inc., Model DHC-8-400 series airplanes. AD 2016-24-03 required repetitive detailed inspections of barrel nuts and cradles, a check of the bolt torque of the preload indicating (PLI) washers, and corrective actions if necessary. This AD retains the requirements of AD 2016-24-03 and requires modifying the airplane by installing a sealing disk to a certain location and replacing certain barrel nuts. This AD was prompted by reports of cracked and corroded barrel nuts found at the mid-spar location of the horizontal-stabilizer-to-vertical-stabilizer attachment joint, and the issuance of new service information that includes a terminal modification. We are issuing this AD to address the unsafe condition on these products.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2018/10/24/2018-23031/airworthiness-directives-bombardier-inc-airplanes)
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