# Airworthiness Directives; Boeing Model 747-400 and 767 Series Airplanes Powered by Pratt & Whitney PW4000 Series Engines
> **Rule** · Final rule. · Published 1999-12-20 · Effective 2000-01-24 · 64 FR 71007
## Document
- **Document number:** 99-32191
- **Category:** airworthiness
- **Manufacturer:** Boeing Model 747-400 and 767 Series
- **Type:** Rule
- **Action:** Final rule.
- **Citation:** 64 FR 71007
- **Publication date:** 1999-12-20
- **Effective date:** 2000-01-24
- **FAA docket:** Docket No. 99-NM-114-AD
## Abstract

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 747-400 and 767 series airplanes, that requires replacement of the existing deactivation pin, pin bushing, and insert flange on each thrust reverser half, with new, improved components. This amendment is prompted by reports of partial deployment of deactivated thrust reversers during landing. The actions specified by this AD are intended to prevent failure of the thrust reverser deactivation pins, which could result in deployment of the thrust reverser in flight and consequent reduced controllability of the airplane.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/1999/12/20/99-32191/airworthiness-directives-boeing-model-747-400-and-767-series-airplanes-powered-by-pratt-and-whitney)
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