# Proposed AD 2001-NM-124-AD: Boeing Model 747-100, 747-200, 747-300, and 747SR Series Airplanes Powered by General Electric CF6-45/50 or Pratt & Whitney JT9D-70 Series Engines

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2001-26-12
- Products: Boeing
- Product type: Aircraft
- Action: Notice of proposed rulemaking (NPRM).
- Published: September 4, 2001, 66 FR 46241
- Comments due: October 19, 2001
- Became: [AD 2001-26-12](https://openairdocs.org/ad/2001-26-12)
- Docket: 2001-NM-124-AD
- FR document: 01-22089
- Official PDF: https://openairdocs.org/files/sha256/2b/16/2b16d1d06c126079c152a45368f0f53e2db52714f441937112b04cfe2b7f8365 (from https://www.govinfo.gov/content/pkg/FR-2001-09-04/pdf/01-22089.pdf)
- Federal Register: https://www.federalregister.gov/documents/2001/09/04/01-22089/airworthiness-directives-boeing-model-747-100-747-200-747-300-and-747sr-series-airplanes-powered-by
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/1FE6D13C4BCF33F886256ABE0069527C.0001
- Page: https://openairdocs.org/proposed/2001-NM-124-AD

## Summary

This document proposes the supersedure of an existing airworthiness directive (AD), applicable to certain Boeing Model 747-100, 747-200, 747-300, and 747SR series airplanes powered by General Electric CF6-45/50 or Pratt & Whitney JT9D-70 series engines, that currently requires a detailed visual inspection of the outboard diagonal brace for heat damage and cracking; and follow-on repetitive inspections and corrective actions, if necessary. This action proposes to require accomplishment of the previously optional replacement of any existing sealant with heat-resistant sealant as terminating action for the repetitive inspections required by this AD. This proposal is prompted by reports of heat damage to the forward end of the diagonal brace after accomplishment of a previous strut and wing modification. The actions specified by the proposed AD are intended to prevent heat damage to the diagonal brace, which could cause cracking, fracture, and possible loss of the diagonal brace load path and consequent separation of the strut and engine from the airplane.

## Notices in this docket

- Sep 4, 2001: Notice of proposed rulemaking (NPRM). (first notice), FR document 01-22089, comments due Oct 19, 2001 (https://www.federalregister.gov/documents/2001/09/04/01-22089/airworthiness-directives-boeing-model-747-100-747-200-747-300-and-747sr-series-airplanes-powered-by)

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