# Proposed AD 98-SW-64-AD: Bell Helicopter Textron Canada Model 407 Helicopters

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2000-04-20
- Action: Notice of proposed rulemaking (NPRM).
- Published: December 8, 1999, 64 FR 68639
- Comments due: February 7, 2000
- Became: [AD 2000-04-20](https://openairdocs.org/ad/2000-04-20)
- Docket: 98-SW-64-AD
- FR document: 99-31818
- Official PDF: https://openairdocs.org/files/sha256/0a/e1/0ae1f73f26301f3ac9ed2b9af354f6e4a0a31a43dfcc4424c8eb55b2a13f6e02 (from https://www.govinfo.gov/content/pkg/FR-1999-12-08/pdf/99-31818.pdf)
- Federal Register: https://www.federalregister.gov/documents/1999/12/08/99-31818/airworthiness-directives-bell-helicopter-textron-canada-model-407-helicopters
- Page: https://openairdocs.org/proposed/98-SW-64-AD

## Summary

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to Bell Helicopter Textron Canada (BHTC) Model 407 helicopters. This proposal would require replacing a certain hydraulic relief valve (valve) with a different valve. This proposal is prompted by the discovery of a manufacturing defect in a valve. The actions specified by the proposed AD are intended to prevent intermittent loss of hydraulic pressure to the flight controls and subsequent loss of control of the helicopter.

## Notices in this docket

- Dec 8, 1999: Notice of proposed rulemaking (NPRM). (first notice), FR document 99-31818, comments due Feb 7, 2000 (https://www.federalregister.gov/documents/1999/12/08/99-31818/airworthiness-directives-bell-helicopter-textron-canada-model-407-helicopters)

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