# Proposed AD FAA-2010-0275: The Boeing Company Model 747-100, 747- 100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400F, 747SR, and 747SP Series Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2010-14-01
- Products: Boeing
- Product type: Aircraft
- Action: Notice of proposed rulemaking (NPRM).
- Published: April 12, 2010, 75 FR 18446
- Comments due: May 27, 2010
- Became: [AD 2010-14-01](https://openairdocs.org/ad/2010-14-01)
- Docket: FAA-2010-0275 (https://www.regulations.gov/docket/FAA-2010-0275, where comments are filed)
- Project: 2009-NM-231-AD
- FR document: 2010-8249
- Official PDF: https://openairdocs.org/files/sha256/21/93/2193484ab500310ba6439985e71b51ce0ad74d2fc2874f8e9f33d07a09faad80 (from https://www.govinfo.gov/content/pkg/FR-2010-04-12/pdf/2010-8249.pdf)
- Federal Register: https://www.federalregister.gov/documents/2010/04/12/2010-8249/airworthiness-directives-the-boeing-company-model-747-100-747-100b-747-100b-sud-747-200b-747-200c
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/21F8203D69608D8B8625770300506A0C.0001
- Page: https://openairdocs.org/proposed/FAA-2010-0275

## Summary

We propose to adopt a new airworthiness directive (AD) for certain Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747- 200F, 747-300, 747-400, 747-400F, 747SR, and 747SP series airplanes. This proposed AD would require reworking or replacing certain duct assemblies in the environmental control system (ECS). This proposed AD results from reports of duct assemblies in the ECS with burned Boeing Material Specification (BMS) 8-39 polyurethane foam insulation. This proposed AD also results from a report from the airplane manufacturer that airplanes were assembled with duct assemblies in the ECS wrapped with BMS 8-39 polyurethane foam insulation, a material of which the fire retardant properties deteriorate with age. We are proposing this AD to prevent a potential electrical arc from igniting the BMS 8-39 polyurethane foam insulation on the duct assemblies of the ECS, which could propagate a small fire and lead to a larger fire that might spread throughout the airplane through the ECS.

## Notices in this docket

- Apr 12, 2010: Notice of proposed rulemaking (NPRM). (first notice), FR document 2010-8249, comments due May 27, 2010 (https://www.federalregister.gov/documents/2010/04/12/2010-8249/airworthiness-directives-the-boeing-company-model-747-100-747-100b-747-100b-sud-747-200b-747-200c)

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