# Proposed AD 99-NM-12-AD: Short Brothers Model SD3-SHERPA, SD3-60 SHERPA, SD3-30, and SD3-60 Series Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 99-18-11
- Action: Notice of proposed rulemaking (NPRM).
- Published: June 28, 1999, 64 FR 34581
- Comments due: July 28, 1999
- Became: [AD 99-18-11](https://openairdocs.org/ad/99-18-11)
- Docket: 99-NM-12-AD
- FR document: 99-16333
- Official PDF: https://openairdocs.org/files/sha256/26/87/268715cd2f646b89289d56f81f70ecf71d582063a578411272d82d8442b7f8da (from https://www.govinfo.gov/content/pkg/FR-1999-06-28/pdf/99-16333.pdf)
- Federal Register: https://www.federalregister.gov/documents/1999/06/28/99-16333/airworthiness-directives-short-brothers-model-sd3-sherpa-sd3-60-sherpa-sd3-30-and-sd3-60-series
- Page: https://openairdocs.org/proposed/99-NM-12-AD

## Summary

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to all Short Brothers Model SD3- SHERPA, SD3-60 SHERPA, SD3-30, and SD3-60 series airplanes. This proposal would require replacement of the existing bolts that secure the elevator control torque tube bearing housing retaining plate with hex head bolts. This proposal is prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by the proposed AD are intended to prevent reduced movement of the elevator controls and consequent reduced controllability of the airplane, as a result of bolts coming loose on the elevator control torque tube bearing housing retaining plate.

## Notices in this docket

- Jun 28, 1999: Notice of proposed rulemaking (NPRM). (first notice), FR document 99-16333, comments due Jul 28, 1999 (https://www.federalregister.gov/documents/1999/06/28/99-16333/airworthiness-directives-short-brothers-model-sd3-sherpa-sd3-60-sherpa-sd3-30-and-sd3-60-series)

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