# Proposed AD FAA-2009-0293: Boeing Model 747-100, -100B, -100B SUD, -200B, -200C, -200F, -300, -400, -400D, -400F, and 747SR Series Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2009-20-12
- Products: Boeing
- Product type: Aircraft
- Action: Notice of proposed rulemaking (NPRM).
- Published: April 1, 2009, 74 FR 14750
- Comments due: May 18, 2009
- Became: [AD 2009-20-12](https://openairdocs.org/ad/2009-20-12)
- Docket: FAA-2009-0293 (https://www.regulations.gov/docket/FAA-2009-0293, where comments are filed)
- Project: 2008-NM-221-AD
- FR document: E9-7273
- Official PDF: https://openairdocs.org/files/sha256/b2/08/b20883be65e34fec6437d07d27cf6b63a8614b638e844bf3edec08368b12117d (from https://www.govinfo.gov/content/pkg/FR-2009-04-01/pdf/E9-7273.pdf)
- Federal Register: https://www.federalregister.gov/documents/2009/04/01/E9-7273/airworthiness-directives-boeing-model-747-100--100b--100b-sud--200b--200c--200f--300--400--400d
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/9D7F36281E62EE3A8625758B00553C20.0001
- Page: https://openairdocs.org/proposed/FAA-2009-0293

## Summary

We propose to adopt a new airworthiness directive (AD) for certain Boeing Model 747 airplanes identified above. This proposed AD would require replacing the inboard trailing edge (TE) flap transmission carbon disk no-back brakes with skewed roller no-back brakes at the TE flap transmission, positions 4 and 5. This proposed AD results from reports of the inboard TE flaps blowing back due to the failure of a transmission carbon disk no-back brake. The no-back brake did not hold the TE flaps in the commanded position. We are proposing this AD to prevent a decrease of the aerodynamic controllability of the airplane, which could adversely affect the airplane's continued safe flight and landing.

## Notices in this docket

- Apr 1, 2009: Notice of proposed rulemaking (NPRM). (first notice), FR document E9-7273, comments due May 18, 2009 (https://www.federalregister.gov/documents/2009/04/01/E9-7273/airworthiness-directives-boeing-model-747-100--100b--100b-sud--200b--200c--200f--300--400--400d)

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