# Airworthiness Directives; Boeing Model 747-400 Series Airplanes Equipped with Pratt & Whitney PW4000 Series Engines
> **Rule** · Final rule. · Published 2000-06-23 · Effective 2000-07-28 · 65 FR 39079
## Document
- **Document number:** 00-15545
- **Category:** airworthiness
- **Manufacturer:** Boeing Model 747-400 Series
- **Type:** Rule
- **Action:** Final rule.
- **Citation:** 65 FR 39079
- **Publication date:** 2000-06-23
- **Effective date:** 2000-07-28
- **FAA docket:** Docket No. 99-NM-66-AD
## Abstract

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 747-400 series airplanes. The AD requires installation of a modification of the thrust reverser control and indication system and wiring on each engine; and repetitive functional tests of that installation to detect discrepancies, and repair, if necessary. This amendment is prompted by the results of a safety review, which revealed that in-flight deployment of a thrust reverser could result in a significant reduction in airplane controllability. The actions specified by this AD are intended to ensure the integrity of the fail-safe features of the thrust reverser system by preventing possible failure modes, which could result in inadvertent deployment of a thrust reverser during flight, and consequent reduced controllability of the airplane.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2000/06/23/00-15545/airworthiness-directives-boeing-model-747-400-series-airplanes-equipped-with-pratt-and-whitney)
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