# Proposed AD 96-SW-29-AD: Sikorsky Aircraft Corporation Model S- 61A, D, E, L, N, NM, R, and V Helicopters

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 98-26-02
- Action: Notice of proposed rulemaking (NPRM).
- Published: September 18, 1997, 62 FR 48961
- Comments due: November 17, 1997
- Became: [AD 98-26-02](https://openairdocs.org/ad/98-26-02)
- Docket: 96-SW-29-AD
- FR document: 97-24795
- Official PDF: https://openairdocs.org/files/sha256/04/9c/049cce1e8c5e1164ee0a1b8a2a8c8a8a414f6cb5d4f9230c7ccf53d150c6827f (from https://www.govinfo.gov/content/pkg/FR-1997-09-18/pdf/97-24795.pdf)
- Federal Register: https://www.federalregister.gov/documents/1997/09/18/97-24795/airworthiness-directives-sikorsky-aircraft-corporation-model-s--61a-d-e-l-n-nm-r-and-v-helicopters
- Page: https://openairdocs.org/proposed/96-SW-29-AD

## Summary

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to Sikorsky Aircraft Corporation (Sikorsky) Model S-61 A, D, E, L, N, NM, R, and V helicopters. This proposal would require a nondestructive inspection (NDI) for cracks in the main rotor shaft (shaft), and require removal of any shaft with a crack and replacement with an airworthy shaft. This proposal would also require appropriate marking of shafts and log book entries by the operator to determine the shaft retirement life, and would establish a new retirement life for the shaft. This proposal is prompted by four reports of cracks occurring in helicopters that were utilized in repetitive external lift (REL) operations. The actions specified by the proposed AD are intended to detect a fatigue crack in the shaft, that could result in shaft structural failure, loss of power to the main rotor, and subsequent loss of control of the helicopter.

## Notices in this docket

- Sep 18, 1997: Notice of proposed rulemaking (NPRM). (first notice), FR document 97-24795, comments due Nov 17, 1997 (https://www.federalregister.gov/documents/1997/09/18/97-24795/airworthiness-directives-sikorsky-aircraft-corporation-model-s--61a-d-e-l-n-nm-r-and-v-helicopters)

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