# Proposed AD 99-NM-208-AD: Boeing Model 747-400 and 767-200 and - 300 Series Airplanes Powered by Pratt & Whitney Model PW4000 Series Engines

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2000-11-28
- Action: Notice of proposed rulemaking (NPRM).
- Published: October 19, 1999, 64 FR 56276
- Comments due: December 3, 1999
- Became: [AD 2000-11-28](https://openairdocs.org/ad/2000-11-28)
- Docket: 99-NM-208-AD
- FR document: 99-27273
- Official PDF: https://openairdocs.org/files/sha256/b4/9b/b49b82be8d9ca99cbf0ca7e2b62379d7801be30d661b1172aa490832cc037808 (from https://www.govinfo.gov/content/pkg/FR-1999-10-19/pdf/99-27273.pdf)
- Federal Register: https://www.federalregister.gov/documents/1999/10/19/99-27273/airworthiness-directives-boeing-model-747-400-and-767-200-and---300-series-airplanes-powered-by
- Page: https://openairdocs.org/proposed/99-NM-208-AD

## Summary

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Boeing Model 747-400 and 767-200 and -300 series airplanes. This proposal would require repetitive inspections to detect damage and wear of the auxiliary track assembly of the thrust reverser, and corrective actions, if necessary. This proposal would also require eventual replacement of the liner and slider, or the entire assembly, with new, improved parts, which, when accomplished, would terminate the repetitive inspections. This proposal is prompted by reports of damage and wear to the auxiliary track assembly. The actions specified by the proposed AD are intended to prevent a slider disengaging from the auxiliary track assembly, which could lead to separation of a portion of the thrust reverser from the airplane during flight, possible impact of separated portions on airplane structure, and consequent possible rapid decompression of the airplane, reduced controllability of the airplane, or reduced structural integrity of the fuselage.

## Notices in this docket

- Oct 19, 1999: Notice of proposed rulemaking (NPRM). (first notice), FR document 99-27273, comments due Dec 3, 1999 (https://www.federalregister.gov/documents/1999/10/19/99-27273/airworthiness-directives-boeing-model-747-400-and-767-200-and---300-series-airplanes-powered-by)

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