[Federal Register: April 11, 2000 (Volume 65, Number 70)]
[Notices]
[Page 19423-19424]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr11ap00-125]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
Proposed Advisory Circular 25.905-X, Minimizing the Hazards From
Propeller Blade and Hub Failures
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of availability of proposed Advisory Circular (AC)
25.905-X and request for comments.
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[[Page 19424]]
SUMMARY: This notice announces the availability of and requests comment
on a proposed advisory circular (AC) that provides 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 relative to design precautions that should be taken to
minimize the hazards to an airplane in the event that a propeller blade
fails or is released by a hub failure. This notice is necessary to give
all interested persons an opportunity to present their views on the
proposed AC.
DATES: Comments must be received on or before June 12, 2000.
ADDRESSES: Send all comments on the proposed AC to: Federal Aviation
Administration, Attn: Michael Dostert, FAA, Transport Airplane
Directorate, Aircraft Certification Service, Propulsion/Mechanical
Systems Branch, ANM-112, 1601 Lind Avenue SW., Renton, Washington
98055-4056. Comments may be inspected at the above address between 7:30
a.m. and 4:00 p.m. weekdays, except Federal holidays.
FOR FURTHER INFORMATION CONTACT: Jill DeMarco, Program Management
Branch, ANM-114, Transport Airplane Directorate, FAA, 1601 Lind Avenue
SW., Renton, Washington 98055-4056; telephone (425) 227-1313.
SUPPLEMENTARY INFORMATION:
Comments Invited
Interested persons are invited to comment on the proposed AC by
submitting such written data, views, or arguments as they may desire.
Commenters must identify the AC by title and submit comments in
duplicate to the address specified above. The Transport Airplane
Directorate will consider all communications received on or before the
closing date for comments before issuing the final AC.
Availability of Proposed AC
The proposed AC can be found and downloaded from the Internet at
http://www.faa.gov/avr/air/airhome.htm, at the link titled ``Draft
AC's'' under the ``Available Information'' drop-down menu. A paper copy
of the proposed AC may be obtained by contacting the person named above
under the caption ``FOR FURTHER INFORMATION CONTACT.''
Discussion
Proposed AC 25.905-X, ``Minimizing the Hazards from Propeller Blade
and Hub Failures,'' has been prepared to provide guidance on one means
of demonstrating compliance with the requirements of Sec. 25.905,
``Propellers,'' of Title 14, Code of Federal Regulations (CFR) part 25,
commonly referred to as part 25 of the Federal Aviation Regulations
(FAR). Part 25 contains the airworthiness standards applicable to
transport category airplanes.
The means of compliance described in proposed AC 25.905-X is
intended to provide guidance to supplement the engineering and
operational judgment that must form the basis of any compliance
findings relative to paragraph Sec. 25.905(d). That paragraph addresses
design precautions that should be taken to minimize the hazards to an
airplane in the event that a propeller blade fails or is released by a
hub failure.
In accordance with Sec. 25.905(d), the hazards that must be
considered include:
1. Damage to structure and vital systems due to the impact of a
failed or released blade, and
2. The consequent unbalance created by such failure or release.
The proposed AC addresses the hazards associated with damage
created by the impact of failed or released propeller blades, and
provides a discussion of design practices to minimize such hazards.
However, it does not address the hazard associated with unbalance
created by such failure or release.
Harmonization of Standards and Guidance
The proposed AC is based on recommendations submitted to the FAA by
the Aviation Rulemaking Advisory Committee (ARAC). The FAA tasked ARAC
(63 FR 50954, September 23, 1998) to provide advice and recommendations
on ``harmonizing'' certain sections of part 25 (including Sec. 25.1183)
with the counterpart standards contained in Joint Aviation Requirements
(JAR) 25. The goal of ``harmonization tasks,'' such as this, is to
ensure that:
Where possible, standards and guidance do not require
domestic and foreign parties to manufacture or operate to different
standards for each country involved; and
The standards and guidance adopted are mutually acceptable
to the FAA and the foreign aviation authorities.
The guidance contained in the proposed AC has been harmonized with
that of the JAA, and provides a method of compliance that has been
found acceptable to both the FAA and JAA.
Issued in Renton, Washington, on March 31, 2000.
Vi L. Lipski,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 00-8848 Filed 4-10-00; 8:45 am]
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