# Proposed AD FAA-2011-1171: The Boeing Company Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2012-02-09
- Products: Boeing
- Product type: Aircraft
- Action: Notice of proposed rulemaking (NPRM).
- Published: November 7, 2011, 76 FR 68666
- Comments due: December 22, 2011
- Became: [AD 2012-02-09](https://openairdocs.org/ad/2012-02-09)
- Docket: FAA-2011-1171 (https://www.regulations.gov/docket/FAA-2011-1171, where comments are filed)
- Project: 2011-NM-101-AD
- FR document: 2011-28758
- Official PDF: https://openairdocs.org/files/sha256/b9/a1/b9a1777bfc44ee66d64473280fe115241091b92dd51c2b53a3d5673049e5f82e (from https://www.govinfo.gov/content/pkg/FR-2011-11-07/pdf/2011-28758.pdf)
- Federal Register: https://www.federalregister.gov/documents/2011/11/07/2011-28758/airworthiness-directives-the-boeing-company-airplanes
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/52C8A5491002B1EA86257941004F7993.0001
- Page: https://openairdocs.org/proposed/FAA-2011-1171

## Summary

We propose to adopt a new airworthiness directive (AD) for certain The Boeing Company Model 737-100, -200, -200C, and -300 series airplanes. This proposed AD was prompted by a report from the airplane manufacturer that airplanes were assembled with air distribution ducts in the environmental control system (ECS) wrapped with Boeing Material Specification (BMS) 8-39 or Aeronautical Materials Specifications (AMS) 3570 polyurethane foam insulation, a material with fire-retardant properties that deteriorate with age. This proposed AD would require reworking certain air distribution ducts in the ECS. We are proposing this AD to prevent ignition of the BMS 8-39 or AMS 3570 polyurethane foam insulation on the duct assemblies of the ECS due to a potential electrical arc, which could start a small fire and lead to a larger fire that may spread throughout the airplane through the ECS.

## Notices in this docket

- Nov 7, 2011: Notice of proposed rulemaking (NPRM). (first notice), FR document 2011-28758, comments due Dec 22, 2011 (https://www.federalregister.gov/documents/2011/11/07/2011-28758/airworthiness-directives-the-boeing-company-airplanes)

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.