# Airworthiness Directives; Sikorsky Aircraft Corporation Model S- 76A, B, and C Helicopters
> **Rule** · Final rule; request for comments. · Published 1999-01-15 · Effective 1999-02-01 · 64 FR 2560
## Document
- **Document number:** 99-907
- **Category:** airworthiness
- **Manufacturer:** Sikorsky
- **Type:** Rule
- **Action:** Final rule; request for comments.
- **Citation:** 64 FR 2560
- **Publication date:** 1999-01-15
- **Effective date:** 1999-02-01
- **FAA docket:** Docket No. 98-SW-37-AD
## Abstract

This document publishes in the Federal Register an amendment adopting Airworthiness Directive (AD) 98-17-15 which was sent previously to all known U.S. owners and operators of Sikorsky Aircraft Corporation Model S-76A, B, and C helicopters by individual letters. This AD requires, before further flight, a one-time visual inspection of the swashplate assembly uniball bearing retainer (retainer) for missing bolts, an inspection with a magnet to detect aluminum bolts, and replacing missing or aluminum bolts with airworthy steel bolts. This amendment is prompted by reports of the installation of aluminum bolts on swashplate assemblies. This condition, if not corrected, could result in failure of the swashplate assembly, loss of the main rotor, and subsequent loss of control of the helicopter.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/1999/01/15/99-907/airworthiness-directives-sikorsky-aircraft-corporation-model-s--76a-b-and-c-helicopters)
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