# Airworthiness Directives; Boeing Model 737 Series Airplanes
> **Rule** · Final rule; request for comments. · Published 1997-03-04 · Effective 1997-03-19 · 62 FR 9679
## Document
- **Document number:** 97-5159
- **Category:** airworthiness
- **Manufacturer:** Boeing Model 737 Series
- **Type:** Rule
- **Action:** Final rule; request for comments.
- **Citation:** 62 FR 9679
- **Publication date:** 1997-03-04
- **Effective date:** 1997-03-19
- **FAA docket:** Docket No. 97-NM-26-AD
## Abstract

This amendment adopts a new airworthiness directive (AD) that is applicable to all Boeing Model 737 series airplanes. This action requires removal of the main rudder power control unit (PCU) and replacement with a serviceable unit. This amendment is prompted by a report of the installation of an incorrect bolt on the main rudder PCU. The actions specified in this AD are intended to prevent cracking of the bearing of the main rudder PCU due to installation of an incorrect bolt; such cracking could result in seizure of the bearing and resultant uncommanded rudder movement.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/1997/03/04/97-5159/airworthiness-directives-boeing-model-737-series-airplanes)
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