# Airworthiness Directives; Pilatus Aircraft Ltd. Model PC-7 Airplanes
> **Rule** · Final rule. · Published 1998-04-09 · Effective 1998-04-28 · 63 FR 17323
## Document
- **Document number:** 98-9153
- **Category:** airworthiness
- **Manufacturer:** Pilatus
- **Type:** Rule
- **Action:** Final rule.
- **Citation:** 63 FR 17323
- **Publication date:** 1998-04-09
- **Effective date:** 1998-04-28
- **FAA docket:** Docket No. 97-CE-149-AD
## Abstract

This amendment adopts a new airworthiness directive (AD) that applies to certain Pilatus Aircraft Ltd. (Pilatus) Model PC-7 airplanes. This AD requires replacing the rudder and elevator pivot arms with parts of improved design. This AD results from reports of cracks in the elevator and rudder trim tab pivot arms on the above- referenced airplanes. The actions specified by this AD are intended to prevent failure of the elevator and rudder caused by fatigue cracking of the pivot arms, which could result in reduced airplane controllability and possible loss of control of the airplane.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/1998/04/09/98-9153/airworthiness-directives-pilatus-aircraft-ltd-model-pc-7-airplanes)
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