# Proposed AD 99-NM-124-AD: Boeing Model 757-200 and −300 Series Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2001-09-01
- Action: Supplemental notice of proposed rulemaking; reopening of comment period.
- Published: September 18, 2000, 65 FR 56268
- Comments due: October 13, 2000
- Became: [AD 2001-09-01](https://openairdocs.org/ad/2001-09-01)
- Docket: 99-NM-124-AD
- FR document: 00-23855
- Official PDF: https://openairdocs.org/files/sha256/fc/a5/fca533e1868aae95eda80f8e20fffe9a1736b69d01d7de398613ef994c87f839 (from https://www.govinfo.gov/content/pkg/FR-2000-09-18/pdf/00-23855.pdf)
- Federal Register: https://www.federalregister.gov/documents/2000/09/18/00-23855/airworthiness-directives-boeing-model-757-200-and-300-series-airplanes
- Page: https://openairdocs.org/proposed/99-NM-124-AD

## Summary

This document revises an earlier proposed airworthiness directive (AD), applicable to all Boeing Model 757-200 series airplanes, that would have required repetitive clearing of the drain passage at the aft end of the main landing gear (MLG) truck beam to ensure moisture and contaminants within the truck beam can properly drain. That proposal was prompted by reports of fracture of MLG truck beams. This new action revises the proposed rule by expanding the applicability and, for certain airplanes, adding a new inspection and follow-on actions. The actions specified by this new proposed AD are intended to prevent stress corrosion cracking, leading to fracture of a MLG truck beam during ground operations, which could result in either reduced controllability of the airplane or a fire.

## Notices in this docket

- Sep 15, 1999: Notice of proposed rulemaking (NPRM). (first notice), FR document 99-23997, comments due Nov 1, 1999 (https://www.federalregister.gov/documents/1999/09/15/99-23997/airworthiness-directives-boeing-model-757-200-series-airplanes)
- Sep 18, 2000: Supplemental notice of proposed rulemaking; reopening of comment period., FR document 00-23855, comments due Oct 13, 2000 (https://www.federalregister.gov/documents/2000/09/18/00-23855/airworthiness-directives-boeing-model-757-200-and-300-series-airplanes)

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