# Airworthiness Directives; Boeing Model 737-300, -400, -500, -600, -700, -700C, -800, and -900, and 747-400 Series Airplanes; and Model 757, 767, and 777 Airplanes
> **Rule** · Final rule. · Published 2009-12-28 · Effective 2010-02-01 · 74 FR 68501
## Document
- **Document number:** E9-29963
- **Category:** airworthiness
- **Type:** Rule
- **Action:** Final rule.
- **Citation:** 74 FR 68501
- **Publication date:** 2009-12-28
- **Effective date:** 2010-02-01
- **FAA docket:** Docket No. FAA-2009-0911
## Abstract

The FAA is adopting a new airworthiness directive (AD) for certain Boeing Model 737-300, -400, -500, -600, -700, -700C, -800, and -900, and 747-400 series airplanes; and Model 757, 767, and 777 airplanes. This AD requires modifying the static inverter by replacing resistor R170 with a new resistor and relocating the new resistor. This AD results from evaluation of the carbon resistor, which revealed a failure mode that can cause the resistor to ignite, involving adjacent capacitors as well. We are issuing this AD to prevent a standby static inverter from overheating, which could result in smoke in the flight deck and cabin and loss of the electrical standby power system.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2009/12/28/E9-29963/airworthiness-directives-boeing-model-737-300--400--500--600--700--700c--800-and--900-and-747-400)
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