# Airworthiness Directives; MD Helicopters, Inc (MDHI) Model 369D and E Helicopters
> **Rule** · Final rule; request for comments. · Published 1999-07-20 · Effective 1999-08-04 · 64 FR 38817
## Document
- **Document number:** 99-18367
- **Category:** airworthiness
- **Manufacturer:** MD
- **Type:** Rule
- **Action:** Final rule; request for comments.
- **Citation:** 64 FR 38817
- **Publication date:** 1999-07-20
- **Effective date:** 1999-08-04
- **FAA docket:** Docket No. 99-SW-40-AD
## Abstract

This document publishes in the Federal Register an amendment adopting Airworthiness Directive (AD) 99-13-09 which was sent previously to all known U.S. owners and operators of MDHI Model 369D and E helicopters by individual letters. This AD requires, prior to further flight, inspecting and replacing, if necessary, a certain four- bladed tail rotor fork (fork) assembly. This AD also requires a repetitive inspection of certain fork assemblies at intervals not to exceed 50 hours time-in-service (TIS) and removing and replacing, if necessary, each unairworthy fork assembly with an airworthy fork assembly before further flight. This amendment is prompted by reports from the manufacturer of the discovery of a discrepant part. The actions specified by this AD are intended to prevent failure of certain fork assemblies, which could cause loss of a tail rotor blade and subsequent loss of control of the helicopter.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/1999/07/20/99-18367/airworthiness-directives-md-helicopters-inc-mdhi-model-369d-and-e-helicopters)
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