# Airworthiness Directives; Construcciones Aeronauticas, S.A. (CASA), Model CN-235 Series Airplanes
> **Rule** · Final rule. · Published 1999-10-22 · Effective 1999-11-26 · 64 FR 56962
## Document
- **Document number:** 99-27325
- **Category:** airworthiness
- **Type:** Rule
- **Action:** Final rule.
- **Citation:** 64 FR 56962
- **Publication date:** 1999-10-22
- **Effective date:** 1999-11-26
- **FAA docket:** Docket No. 99-NM-117-AD
## Abstract

This amendment supersedes an existing airworthiness directive (AD), applicable to all CASA Model CN-235 series airplanes, that currently requires repetitive eddy current inspections to detect fatigue cracks in the nose landing gear (NLG) turning tube, and replacement of cracked tubes. This amendment adds a requirement for the replacement of the existing NLG turning tube constructed of aluminum alloy with a new NLG turning tube made of steel; such replacement terminates the repetitive inspections. This amendment is prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by this AD are intended to prevent fatigue cracking and failure of the NLG turning tube, which could result in reduced structural integrity of the NLG.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/1999/10/22/99-27325/airworthiness-directives-construcciones-aeronauticas-sa-casa-model-cn-235-series-airplanes)
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