# Proposed AD 99-NM-330-AD: Boeing Model 747 Series Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2000-12-19
- Action: Notice of proposed rulemaking (NPRM).
- Published: February 2, 2000, 65 FR 4900
- Comments due: March 20, 2000
- Became: [AD 2000-12-19](https://openairdocs.org/ad/2000-12-19)
- Docket: 99-NM-330-AD
- FR document: 00-2090
- Official PDF: https://openairdocs.org/files/sha256/23/1d/231d1db341808dcb7f6b5d4deb37bb9c69a15dc22340da8cfa711ac9d902abcb (from https://www.govinfo.gov/content/pkg/FR-2000-02-02/pdf/00-2090.pdf)
- Federal Register: https://www.federalregister.gov/documents/2000/02/02/00-2090/airworthiness-directives-boeing-model-747-series-airplanes
- Page: https://openairdocs.org/proposed/99-NM-330-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 repetitive inspections of the aft pressure bulkhead to detect cracking, and repair, if necessary. This proposal is prompted by a report of fatigue cracking found in the upper half of the aft pressure bulkhead. The actions specified by the proposed AD are intended to detect and correct cracking in the aft pressure bulkhead, which could result in rapid decompression of the fuselage or overpressurization of the tail section.

## Notices in this docket

- Feb 2, 2000: Notice of proposed rulemaking (NPRM). (first notice), FR document 00-2090, comments due Mar 20, 2000 (https://www.federalregister.gov/documents/2000/02/02/00-2090/airworthiness-directives-boeing-model-747-series-airplanes)

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