# Airworthiness Directives; Boeing Model 747-100, -100B, -100B SUD, -200B, -200C, -200F, -300, -400, -400D, -400F, and 747SR Series Airplanes
> **Rule** · Final rule. · Published 2009-10-01 · Effective 2009-11-05 · 74 FR 50686
## Document
- **Document number:** E9-23555
- **Category:** airworthiness
- **Type:** Rule
- **Action:** Final rule.
- **Citation:** 74 FR 50686
- **Publication date:** 2009-10-01
- **Effective date:** 2009-11-05
- **FAA docket:** Docket No. FAA-2009-0293
## Abstract

We are adopting a new airworthiness directive (AD) for certain Boeing Model 747 airplanes identified above. This AD requires 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 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 issuing 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.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2009/10/01/E9-23555/airworthiness-directives-boeing-model-747-100--100b--100b-sud--200b--200c--200f--300--400--400d)
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