# Airworthiness Directives; British Aerospace HP137 Mk1, Jetstream Series 200, and Jetstream Models 3101 and 3201 Airplanes
> **Rule** · Final rule. · Published 1999-03-18 · Effective 1999-04-26 · 64 FR 13325
## Document
- **Document number:** 99-6101
- **Category:** airworthiness
- **Type:** Rule
- **Action:** Final rule.
- **Citation:** 64 FR 13325
- **Publication date:** 1999-03-18
- **Effective date:** 1999-04-26
- **FAA docket:** Docket No. 98-CE-92-AD
## Abstract

This amendment adopts a new airworthiness directive (AD) that applies to all British Aerospace HP137 Mk1, Jetstream series 200, and Jetstream Models 3101 and 3201 airplanes. This AD requires inspecting the elevator bias spring assembly for correct installation and to assure that the correctly manufactured bias spring is installed. This AD also requires replacing any incorrectly manufactured bias spring, reworking any incorrectly installed bias spring assembly, inspecting the link assembly for distortion or damage, and replacing any distorted and/or damaged parts. This AD is the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for the United Kingdom. The actions specified by this AD are intended to prevent failure of the bearings in the elevator down bias spring assembly caused by the installation of an incorrectly manufactured bias spring or damage or distortion to the assembly, which could result in reduced or loss of control of the airplane.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/1999/03/18/99-6101/airworthiness-directives-british-aerospace-hp137-mk1-jetstream-series-200-and-jetstream-models-3101)
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