# Proposed AD 99-NM-29-AD: Short Brothers Model SD3-30, SD3-60, SD3-SHERPA, and SD3-60 SHERPA Series Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 99-21-02
- Action: Notice of proposed rulemaking (NPRM).
- Published: June 28, 1999, 64 FR 34582
- Comments due: July 28, 1999
- Became: [AD 99-21-02](https://openairdocs.org/ad/99-21-02)
- Docket: 99-NM-29-AD
- FR document: 99-16332
- Official PDF: https://openairdocs.org/files/sha256/b5/24/b5249adf4f486de287578e6efa86263a7dec1f0da111d49c1b60e04e850d46fb (from https://www.govinfo.gov/content/pkg/FR-1999-06-28/pdf/99-16332.pdf)
- Federal Register: https://www.federalregister.gov/documents/1999/06/28/99-16332/airworthiness-directives-short-brothers-model-sd3-30-sd3-60-sd3-sherpa-and-sd3-60-sherpa-series
- Page: https://openairdocs.org/proposed/99-NM-29-AD

## Summary

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to all Short Brothers Model SD3-30, SD3-60, SD3-SHERPA, and SD3-60 SHERPA series airplanes. This proposal would require detailed visual and borescopic inspections to detect corrosion of the engine mounting tube assembly, and replacement of corroded parts with new or serviceable parts. 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 failure of the engine mounting tube assembly, which could result in loss of the engine in flight.

## Notices in this docket

- Jun 28, 1999: Notice of proposed rulemaking (NPRM). (first notice), FR document 99-16332, comments due Jul 28, 1999 (https://www.federalregister.gov/documents/1999/06/28/99-16332/airworthiness-directives-short-brothers-model-sd3-30-sd3-60-sd3-sherpa-and-sd3-60-sherpa-series)

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