# Proposed AD FAA-2006-25001: The Boeing Company Model 737-600, -700, -700C, -800, -900, and -900ER Series Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2012-02-14
- Products: Boeing
- Product type: Aircraft
- Action: Supplemental notice of proposed rulemaking (NPRM); reopening of comment period.
- Published: October 11, 2011, 76 FR 62649
- Comments due: November 25, 2011
- Became: [AD 2012-02-14](https://openairdocs.org/ad/2012-02-14)
- Docket: FAA-2006-25001 (https://www.regulations.gov/docket/FAA-2006-25001, where comments are filed)
- Project: 2006-NM-079-AD
- FR document: 2011-26104
- Official PDF: https://openairdocs.org/files/sha256/1c/b5/1cb5a2a47491f24248c86899c9eced1a2a0467033de2ce26dff6a5bd0745a6ae (from https://www.govinfo.gov/content/pkg/FR-2011-10-11/pdf/2011-26104.pdf)
- Federal Register: https://www.federalregister.gov/documents/2011/10/11/2011-26104/airworthiness-directives-the-boeing-company-model-737-600--700--700c--800--900-and--900er-series
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/0D2EF37520416CE3862579260056149E.0001
- Page: https://openairdocs.org/proposed/FAA-2006-25001

## Summary

We are revising an earlier proposed airworthiness directive (AD) for the products listed above. That second supplemental NPRM proposed a one-time inspection to determine the part numbers of the aero/fire seals of the blocker doors on the thrust reverser torque boxes on the engines, and replacing affected aero/fire seals with new, improved aero/fire seals. That second supplemental NPRM was prompted by a report that the top 3 inches of the aero/fire seals of the blocker doors on the thrust reverser torque boxes are not fireproof. This action revises the second supplemental NPRM by prohibiting installation of certain non-fireproof thrust reverser seals. We are proposing this third supplemental NPRM to prevent a fire in the fan compartment (a fire zone) from migrating through the seal to a flammable fluid in the thrust reverser actuator compartment (a flammable fluid leakage zone), which could result in an uncontrolled fire. Since these actions impose an additional burden over that proposed in the second supplemental NPRM, we are reopening the comment period to allow the public the chance to comment on these proposed changes.

## Notices in this docket

- Jun 13, 2006: Notice of proposed rulemaking (NPRM). (first notice), FR document E6-9163, comments due Jul 28, 2006 (https://www.federalregister.gov/documents/2006/06/13/E6-9163/airworthiness-directives-boeing-model-737-600--700--700c--800-and--900-series-airplanes)
- Sep 3, 2008: Supplemental notice of proposed rulemaking (NPRM); reopening of comment period., FR document E8-20341, comments due Sep 29, 2008 (https://www.federalregister.gov/documents/2008/09/03/E8-20341/airworthiness-directives-boeing-model-737-600--700--700c--800--900-and--900er-series-airplanes)
- Jul 16, 2009: Supplemental notice of proposed rulemaking (NPRM); reopening of comment period., FR document E9-16943, comments due Aug 10, 2009 (https://www.federalregister.gov/documents/2009/07/16/E9-16943/airworthiness-directives-boeing-model-737-600--700--700c--800--900-and--900er-series-airplanes)
- Oct 11, 2011: Supplemental notice of proposed rulemaking (NPRM); reopening of comment period., FR document 2011-26104, comments due Nov 25, 2011 (https://www.federalregister.gov/documents/2011/10/11/2011-26104/airworthiness-directives-the-boeing-company-model-737-600--700--700c--800--900-and--900er-series)

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