# Proposed AD 99-NM-65-AD: Boeing Model 747 Series Airplanes Equipped With Pratt & Whitney JT9D-70 Series Engines

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2000-10-17
- Action: Notice of proposed rulemaking (NPRM).
- Published: February 4, 2000, 65 FR 5459
- Comments due: March 20, 2000
- Became: [AD 2000-10-17](https://openairdocs.org/ad/2000-10-17)
- Docket: 99-NM-65-AD
- FR document: 00-2415
- Official PDF: https://openairdocs.org/files/sha256/c0/36/c0362d8febbb3a05e640ee51a899d8b73313c310057c744edcf67cbebaec6166 (from https://www.govinfo.gov/content/pkg/FR-2000-02-04/pdf/00-2415.pdf)
- Federal Register: https://www.federalregister.gov/documents/2000/02/04/00-2415/airworthiness-directives-boeing-model-747-series-airplanes-equipped-with-pratt-and-whitney-jt9d-70
- Page: https://openairdocs.org/proposed/99-NM-65-AD

## Summary

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Boeing Model 747 series airplanes. This proposal would require inspections, tests, and certain modifications of the thrust reverser control and indication system and wiring on each engine, and corrective action, if necessary. This proposal also would require installation of a terminating modification, and repetitive functional tests of that installation to detect discrepancies, and repair, if necessary. This proposal is prompted by the results of a safety review, which revealed that in- flight deployment of a thrust reverser could result in significant reduction in airplane controllability. The actions specified by the proposed 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.

## Notices in this docket

- Feb 4, 2000: Notice of proposed rulemaking (NPRM). (first notice), FR document 00-2415, comments due Mar 20, 2000 (https://www.federalregister.gov/documents/2000/02/04/00-2415/airworthiness-directives-boeing-model-747-series-airplanes-equipped-with-pratt-and-whitney-jt9d-70)

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.