# Airworthiness Directives; Saab Model SAAB 340B and SAAB 2000 Series Airplanes
> **Rule** · Final rule. · Published 1998-06-03 · Effective 1998-07-08 · 63 FR 30117
## Document
- **Document number:** 98-14221
- **Category:** airworthiness
- **Manufacturer:** Saab Model SAAB 340B and SAAB 2000 Series
- **Type:** Rule
- **Action:** Final rule.
- **Citation:** 63 FR 30117
- **Publication date:** 1998-06-03
- **Effective date:** 1998-07-08
- **FAA docket:** Docket No. 97-NM-134-AD
## Abstract

This amendment adopts a new airworthiness directive (AD), applicable to certain Saab Model SAAB 340B and SAAB 2000 series airplanes, that requires modification of the check valves of the airfoil de-icing system, or replacement of the check valves with improved valves. This amendment is prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by this AD are intended to prevent failure of the check valves, which could result in loss of airfoil de- icing capability during single engine operation, and consequent reduced controllability of the airplane.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/1998/06/03/98-14221/airworthiness-directives-saab-model-saab-340b-and-saab-2000-series-airplanes)
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