# Proposed AD FAA-2012-0689: Sikorsky Aircraft-Manufactured Model S- 64F Helicopters

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2012-26-06
- Products: Sikorsky
- Product type: Aircraft
- Action: Notice of proposed rulemaking (NPRM).
- Published: June 29, 2012, 77 FR 38744
- Comments due: August 28, 2012
- Became: [AD 2012-26-06](https://openairdocs.org/ad/2012-26-06)
- Docket: FAA-2012-0689 (https://www.regulations.gov/docket/FAA-2012-0689, where comments are filed)
- Project: 2009-SW-065-AD
- FR document: 2012-15978
- Official PDF: https://openairdocs.org/files/sha256/5d/77/5d778a9c5eb6cc47eed85dc6f11cca425a50227f0432b756e63e77dd882a55ee (from https://www.govinfo.gov/content/pkg/FR-2012-06-29/pdf/2012-15978.pdf)
- Federal Register: https://www.federalregister.gov/documents/2012/06/29/2012-15978/airworthiness-directives-sikorsky-aircraft-manufactured-model-s-64f-helicopters
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/C8920FE9392439F086257A2C004CC990.0001
- Page: https://openairdocs.org/proposed/FAA-2012-0689

## Summary

We propose to supersede an existing airworthiness directive (AD) for the Sikorsky Aircraft Corporation-manufactured Model S-64F helicopters, now under the Erickson Air-Crane Incorporated (Erickson) Model S-64F type certificate. That AD currently requires inspections, rework, and replacement, if necessary, of the main gearbox (MGB) second stage lower planetary plate (plate). Since we issued that AD, the manufacturer has conducted a configuration review and analysis, and a review of the service history of certain components. The proposed actions are intended to establish life limits for certain components, remove various parts from service, and require consistency in the part numbers of certain four bladed tail rotor (T/R) assemblies to prevent fatigue cracking, failure from static overload, and subsequent loss of control of the helicopter.

## Notices in this docket

- Jun 29, 2012: Notice of proposed rulemaking (NPRM). (first notice), FR document 2012-15978, comments due Aug 28, 2012 (https://www.federalregister.gov/documents/2012/06/29/2012-15978/airworthiness-directives-sikorsky-aircraft-manufactured-model-s-64f-helicopters)

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