[Federal Register Volume 65, Number 214 (Friday, November 3, 2000)]
[Notices]
[Page 66283]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-28295]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration


Advisory Circular 25.905-1, Minimizing the Hazards From Propeller 
Blade and Hub Failures

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of issuance of advisory circular.

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SUMMARY: This notice announces the issuance of Advisory Circular (AC) 
25.905-1, Minimizing the Hazards from Propeller Blade and Hub Failures. 
The AC describes methods acceptable to the Administrator for showing 
compliance with the airworthiness standards for propeller installations 
on transport category airplanes. The guidance provided in the AC 
supplements the engineering and operational judgment that must form the 
basis of any compliance findings on design precautions to minimize the 
hazards to an airplane if a propeller blade fails or is released by a 
hub failure.

DATES: Advisory Circular 25.905-1 was issued on September 27, 2000, by 
the Manager of the Transport Airplane Directorate, Aircraft 
Certification Service, Federal Aviation Administration.

How to Obtain Copies:  You can get a paper copy of AC 25.905-1 by 
writing to U.S. Department of Transportation, Subsequent Distribution 
Center, SVC-121.23, Ardmore East Business Center, 3341 Q 75th Avenue, 
Landover, Maryland 20785. You also can find the AC on the Internet at 
http://www.faa.gov/avr/air/airhome.htm, at the link titled ``Advisory 
Circulars'' under the ``Available Information'' drop-down menu.

FOR FURTHER INFORMATION CONTACT: For technical issues, contact Michael 
Dostert, FAA, Transport Airplane Directorate, Aircraft Certification 
Service, Propulsion/Mechanical Systems Branch, ANM-112, 1601 Lind 
Avenue SW., Renton, Washington 98055-4056; telephone (425) 227-2132; 
fax (425) 227-1320; e-mail [email protected].
    For other information contact: Jill DeMarco, FAA, Transport 
Airplane Directorate, Program Management Branch, ANM-114, 1601 Lind 
Avenue SW., Renton, Washington 98055-4056; telephone (425) 227-1313; 
fax (425) 227-1320.

SUPPLEMENTARY INFORMATION:

Discussion of Comments

    On March 31, 2000, the FAA issued a notice of the availability of 
proposed Advisory Circular (AC) 25.905-X, ``Minimizing the Hazards from 
Propeller Blade and Hub Failures.'' That notice was published in the 
Federal Register on April 11, 2000 (65 FR 19423), and requested public 
comment on the proposed AC document. Only one commenter filed comments 
to the proposed AC.
    The commenter points out that, in the discussion of the ``Purpose'' 
of the AC, the FAA stated that the AC does not address hazards 
associated with unbalance created by blade release or similar failures. 
However, unbalance vibratory forces could be significant and can 
interfere with the required corrective actions. The commenter asks why 
the FAA did not cover this issue in the AC, and if we will address it 
in another AC.
    We agree that imbalance is a critical issue following a propeller 
or hub failure. Structural issues and the flightcrew's ability to cope 
with the failure are of concern. We are considering separate action to 
address these issues. We have asked the Aviation Rulemaking Advisory 
Committee (ARAC) to review these issues and provide recommendations for 
further action.

    Issued in Renton, Washington, on October 27, 2000.
John J. Hickey,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-28295 Filed 11-2-00; 8:45 am]
BILLING CODE 4910-13-U