# Airworthiness Directives; Bombardier Model DHC-8-401 and -402 Airplanes
> **Rule** · Final rule. · Published 2004-03-25 · Effective 2004-04-29 · 69 FR 15233
## Document
- **Document number:** 04-6501
- **Category:** airworthiness
- **Manufacturer:** Bombardier Model DHC-8-401 and -402
- **Type:** Rule
- **Action:** Final rule.
- **Citation:** 69 FR 15233
- **Publication date:** 2004-03-25
- **Effective date:** 2004-04-29
- **FAA docket:** Docket No. 2002-NM-120-AD
## Abstract

This amendment adopts a new airworthiness directive (AD), applicable to certain Bombardier Model DHC-8-401 and -402 airplanes, that requires modifying the wiring of the rudder trim switch, inspecting all wiring on the back of the aileron/rudder trim control panel for chafing, and replacing any chafed wiring with new wiring. This action is necessary to prevent a short circuit on the aileron/ rudder trim control panel that could cause a runaway condition of the rudder trim actuator, which could result in reduced controllability of the airplane. This action is intended to address the identified unsafe condition.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2004/03/25/04-6501/airworthiness-directives-bombardier-model-dhc-8-401-and--402-airplanes)
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