# Proposed AD 99-NM-326-AD: Boeing Model 747-400 Series Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2000-25-11
- Action: Notice of proposed rulemaking (NPRM).
- Published: June 28, 2000, 65 FR 39828
- Comments due: August 14, 2000
- Became: [AD 2000-25-11](https://openairdocs.org/ad/2000-25-11)
- Docket: 99-NM-326-AD
- FR document: 00-16358
- Official PDF: https://openairdocs.org/files/sha256/15/7a/157a39787698cfcbe50ab3c970faf167f21c319037aacff6e299aeda91cf9c6f (from https://www.govinfo.gov/content/pkg/FR-2000-06-28/pdf/00-16358.pdf)
- Federal Register: https://www.federalregister.gov/documents/2000/06/28/00-16358/airworthiness-directives-boeing-model-747-400-series-airplanes
- Page: https://openairdocs.org/proposed/99-NM-326-AD

## Summary

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Boeing Model 747-400 series airplanes. This proposal would require repetitive inspections to detect fatigue cracking of the longeron splice fittings at stringer 11 on the left and right sides at body station 2598, and various follow-on actions. This action is necessary to detect and correct fatigue cracking of the longeron splice fittings and subsequent damage to adjacent structure. Such damage could result in the inability of the structure to carry horizontal stabilizer flight loads, and consequent reduced controllability of the horizontal stabilizer. This action is intended to address the identified unsafe condition.

## Notices in this docket

- Jun 28, 2000: Notice of proposed rulemaking (NPRM). (first notice), FR document 00-16358, comments due Aug 14, 2000 (https://www.federalregister.gov/documents/2000/06/28/00-16358/airworthiness-directives-boeing-model-747-400-series-airplanes)

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