# Proposed AD FAA-2010-1301: MD Helicopters, Inc. (MDHI) Model MD900 Helicopters

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2011-22-08
- Products: MD Helicopter
- Product type: Aircraft
- Action: Notice of proposed rulemaking (NPRM).
- Published: January 14, 2011, 76 FR 2607
- Comments due: March 15, 2011
- Became: [AD 2011-22-08](https://openairdocs.org/ad/2011-22-08)
- Docket: FAA-2010-1301 (https://www.regulations.gov/docket/FAA-2010-1301, where comments are filed)
- Project: 2010-SW-008-AD
- FR document: 2011-726
- Official PDF: https://openairdocs.org/files/sha256/da/66/da667fcfb30faeb434cbbe72c82484c30b65ae080926f33afe2f01c43a19155c (from https://www.govinfo.gov/content/pkg/FR-2011-01-14/pdf/2011-726.pdf)
- Federal Register: https://www.federalregister.gov/documents/2011/01/14/2011-726/airworthiness-directives-md-helicopters-inc-mdhi-model-md900-helicopters
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/DF0613353D908C0C86257818004D5015.0001
- Page: https://openairdocs.org/proposed/FAA-2010-1301

## Summary

This document proposes superseding an existing airworthiness directive (AD) for MDHI Model MD900 helicopters. That AD currently requires turning on both Vertical Stabilizer Control System (VSCS) switches and turning off the autopilot (AP/SAS) switch; pulling certain AP/SAS circuit breakers; installing a placard near the AP/SAS master switch; installing an airspeed limitation placard on the instrument panel; and making changes to the Rotorcraft Flight Manual (RFM). This action would retain those requirements and would provide an option of replacing each affected tube adapter with a newly-designed tube adapter, which would provide terminating action for the unsafe condition. This proposal is prompted by the manufacturer introducing an improved, newly-designed tube adapter. The actions specified by this AD are intended to prevent loss of yaw control and subsequent loss of control of the helicopter.

## Notices in this docket

- Jan 14, 2011: Notice of proposed rulemaking (NPRM). (first notice), FR document 2011-726, comments due Mar 15, 2011 (https://www.federalregister.gov/documents/2011/01/14/2011-726/airworthiness-directives-md-helicopters-inc-mdhi-model-md900-helicopters)

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