# Airworthiness Directives; MD Helicopters, Inc. Model MD900 Helicopters
> **Rule** · Final rule; request for comments. · Published 2002-12-11 · Effective 2002-12-26 · 67 FR 76109
## Document
- **Document number:** 02-31176
- **Category:** airworthiness
- **Manufacturer:** MD
- **Type:** Rule
- **Action:** Final rule; request for comments.
- **Citation:** 67 FR 76109
- **Publication date:** 2002-12-11
- **Effective date:** 2002-12-26
- **FAA docket:** Docket No. 2002-SW-50-AD
## Abstract

This document publishes in the Federal Register an amendment adopting Airworthiness Directive (AD) 2002-22-51, which was sent previously to all known U.S. owners and operators of MD Helicopters, Inc. (MDHI) Model MD900 helicopters by individual letters. This AD requires, before further flight, certain procedures and inspections of the main rotor support static mast (mast) and the mast threads for any crack or pitting. If any crack or pitting is found, this AD requires removing the mast from service. The actions specified by this AD are intended to detect any crack or pitting in the mast that could result in failure of the mast, separation of the main rotor, and subsequent loss of control of the helicopter.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2002/12/11/02-31176/airworthiness-directives-md-helicopters-inc-model-md900-helicopters)
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