# Proposed AD FAA-2005-23250: Boeing Model 747-400 Series Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2006-12-10
- Products: Boeing
- Product type: Aircraft
- Action: Notice of proposed rulemaking (NPRM).
- Published: December 9, 2005, 70 FR 73171
- Comments due: January 23, 2006
- Became: [AD 2006-12-10](https://openairdocs.org/ad/2006-12-10)
- Docket: FAA-2005-23250 (https://www.regulations.gov/docket/FAA-2005-23250, where comments are filed)
- Project: 2005-NM-150-AD
- FR document: 05-23833
- Official PDF: https://openairdocs.org/files/sha256/aa/f4/aaf43a5c8bc8ba4a49d3e9acfaea36279c1176bee12486a41087882dba35c492 (from https://www.govinfo.gov/content/pkg/FR-2005-12-09/pdf/05-23833.pdf)
- Federal Register: https://www.federalregister.gov/documents/2005/12/09/05-23833/airworthiness-directives-boeing-model-747-400-series-airplanes
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/202AD16D94C4CC79862570D2004F43B2.0001
- Page: https://openairdocs.org/proposed/FAA-2005-23250

## Summary

The FAA proposes to adopt a new airworthiness directive (AD) for certain Boeing Model 747-400 series airplanes. This proposed AD would require inspecting the support bracket of the crew oxygen cylinder installation to determine the manufacturing date marked on the support, and performing corrective action if necessary. This proposed AD results from a report indicating that certain oxygen cylinder supports may not have been properly heat-treated. We are proposing this AD to prevent failure of the oxygen cylinder support under the most critical flight load conditions, which could cause the oxygen cylinder to come loose and leak oxygen. Leakage of oxygen could result in oxygen being unavailable for the flightcrew or could result in a fire hazard in the vicinity of the leakage.

## Notices in this docket

- Dec 9, 2005: Notice of proposed rulemaking (NPRM). (first notice), FR document 05-23833, comments due Jan 23, 2006 (https://www.federalregister.gov/documents/2005/12/09/05-23833/airworthiness-directives-boeing-model-747-400-series-airplanes)

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