[Federal Register Volume 71, Number 78 (Monday, April 24, 2006)]
[Notices]
[Page 21090]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 06-3858]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

[Policy Statement No. ANM-05-115-019]


Interim Guidelines for Certification and Continued Airworthiness 
of Unbalanced Control Surfaces With Freeplay and Other Nonlinear 
Features

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed interim guidelines; request for comments.

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SUMMARY: The Federal Aviation Administration (FAA) announces the 
availability of proposed Interim Guidelines for Certification and 
Continued Airworthiness of Unbalanced Control Surfaces with Freeplay 
and Other Nonlinear Features.

DATES: Send your comments on or before May 25, 2006.

ADDRESSES: Address your comments to the individual identified under FOR 
FURTHER INFORMATION CONTACT.

FOR FURTHER INFORMATION CONTACT: Gerald Lakin, Federal Aviation 
Administration, Transport Airplane Directorate, Transport Standards 
Staff, Standardization Branch, ANM-113, 1601 Lind Avenue, SW., Renton, 
WA 98055-4056; telephone (425) 227-1187; fax (425) 227-1320; e-mail: 
[email protected].

SUPPLEMENTARY INFORMATION:

Comments Invited

    The proposed memorandum is available on the Internet at the 
following addresses: http://www.airweb.faa.gov/rgl, and http://www.faa.gov/aircraft/draft_docs. If you do not have access to the 
Internet, you can obtain a copy of the proposed memorandum by 
contacting the person listed under FOR FURTHER INFORMATION CONTACT.
    The FAA invites your comments on this proposed memorandum. We will 
accept your comments, data, views, or arguments by letter, fax, or e-
mail. Send your comments to the person indicated in FOR FURTHER 
INFORMATION CONTACT. Mark your comments, ``Comments to Policy Statement 
No. ANM-05-115-019.''
    Use the following format when preparing your comments:
     Organize your comments issue-by-issue.
     For each issue, state what specific change you are 
requesting to the proposed interim guidelines.
     Include justification, reasons, or data for each change 
you are requesting.
    We also welcome comments in support of the proposed interim 
guidelines.
    We will consider all communications received on or before the 
closing date for comments. We may change the proposed interim 
guidelines because of the comments received.

Background

    This memorandum clarifies FAA guidance on the design, 
certification, and continued airworthiness of control surfaces that 
rely on retention of restraint stiffness for flutter prevention. These 
control surfaces typically do not have added mass balance, but there 
are some that are partially mass balanced for which the guidelines 
would also apply. This memorandum provides acceptable means of 
establishing and certifying freeplay limits and inspection procedures, 
provides guidance for managing freeplay over the airplane service life, 
and provides a means of finding compliance for control system designs 
whose failure can result in a nonlinear aeroelastic configuration and 
limit cycle oscillation (LCO). This memorandum provides interim 
guidelines and standardized methods of compliance that address the 
inadequacies of current guidance, until the FAA revises the applicable 
guidance contained in AC 25.629-1A.

    Issued in Renton, Washington, on April 9, 2006.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 06-3858 Filed 4-21-06; 8:45 am]
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