Transportation Department, Federal Aviation Administration
The FAA is adopting a new airworthiness directive (AD) for The Boeing Company Model 747-400 series airplanes modified by certain supplemental type certificates (STCs). This AD was prompted by a report of a ruptured crew oxygen bottle flexible hose and arcing damage on an adjacent cargo loading system wiring harness. This AD requires a detailed inspection of the crew oxygen bottle flexible hoses and adjacent wire harnesses for chafing and arcing damage and for a minimum clearance between the crew oxygen bottle flexible hoses and adjacent wiring harnesses, and applicable repairs. The FAA is issuing this AD to address the unsafe condition on these products.
Document Headings Document headings vary by document type but may contain the following: the agency or agencies that issued and signed a document the number of the CFR title and the number of each part the document amends, proposes to amend, or is directly related to the agency docket number / agency internal file number the RIN which identifies each regulatory action listed in the Unified Agenda of Federal Regulatory and Deregulatory Actions See the Document Drafting Handbook for more details. Department of Transportation Federal Aviation Administration 14 CFR Part 39 [Docket No. FAA-2026-3486; Project Identifier MCAI-2026-00002-T; Amendment 39-23314; AD 2026-08-06] RIN 2120-AA64 ( printed page 21373) AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule; request for comments. SUMMARY: The FAA is adopting a new airworthiness directive (AD) for The Boeing Company Model 747-400 series airplanes modified by certain supplemental type certificates (STCs). This AD was prompted by a report of a ruptured crew oxygen bottle flexible hose and arcing damage on an adjacent cargo loading system wiring harness. This AD requires a detailed inspection of the crew oxygen bottle flexible hoses and adjacent wire harnesses for chafing and arcing damage and for a minimum clearance between the crew oxygen bottle flexible hoses and adjacent wiring harnesses, and applicable repairs. The FAA is issuing this AD to address the unsafe condition on these products. DATES: This AD is effective May 7, 2026. The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of May 7, 2026. The FAA must receive comments on this AD by June 8, 2026. ADDRESSES: You may send comments, using the procedures found in 14 CFR 11.43 and 11.45 , by any of the following methods: Federal eRulemaking Portal: Go to regulations.gov . Follow the instructions for submitting comments. Fax: 202-493-2251. Mail: U.S. Department of Transportation, D…
Citation: 91 FR 21373
