[Federal Register Volume 63, Number 238 (Friday, December 11, 1998)]
[Notices]
[Pages 68497-68498]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-32967]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration


Proposed Advisory Circular 25-XX, Certification of Transport 
Airplane Mechanical Systems

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of availability of proposed Advisory Circular (AC) 25-XX 
and request for comments.

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SUMMARY: This notice announces the availability of and requests 
comments on a proposed advisory circular (AC) which provides methods 
acceptable to the Administrator for showing compliance with the 
provisions of subparts D and F of 14 CFR part 25 regarding the type 
certification requirements for transport airplane mechanical systems. 
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 April 12, 1999.

ADDRESSES: Send all comments on proposed AC to: Federal Aviation 
Administration, Attention: Mahinder Wahi, Propulsion/Mechanical 
Systems/Crashworthiness/Noise Branch, ANM-112, Transport Airplane 
Directorate, Aircraft Certification Service, 1601 Lind Avenue SW, 
Renton, WA 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:
Toni Jackson, Transport Standards Staff, at the address above, 
telephone (425) 227-2112.


[[Page 68498]]


SUPPLEMENTARY INFORMATION: 

Comments Invited

    A copy of the draft AC may be obtained by contacting the person 
named above under FOR FURTHER INFORMATION CONTACT. Interested persons 
are invited to comment on the proposed AC by submitting such written 
data, views, or arguments as they may desire. Commenters should 
identify AC 25-XX, and submit comments, in duplicate, to the address 
specified above. All communications received on or before the closing 
date for comments will be considered by the Transport Standards Staff 
before issuing the final AC.

Discussion

    This AC contains guidance for the latest amendment of the 
regulations and applies to all transport category airplanes for which a 
new, amended, or supplemental type certificate is required. This 
guidance should be applied to any portion of the airplane mechanical 
systems that has been modified. In the past, advisory and guidance 
information applicable to transport airplane mechanical systems has 
been formally published as AC's. Advisory circulars have not been 
developed for all of the regulatory requirements applicable to 
transport airplane mechanical systems, however. In many instances, 
certification of new technology airplanes resulted in the need to 
interpret the existing regulations and to apply new regulations. Issue 
papers and special conditions were generated to document the compliance 
method agreed upon between the applicant and the FAA. In other 
instances, applicants, FAA Aircraft Certification Office (ACO) 
managers, and foreign regulatory authorities have requested 
interpretation of the intent of specific regulations. This guidance was 
documented in the form of policy memorandums that were distributed to 
all ACOs, letters to applicants and foreign airworthiness authorities, 
and issue papers. In many instances, this information was not organized 
in a manner that allowed easy access, and applicants were not aware of 
revised policy. This AC formalizes existing policy so that the public 
and FAA personnel have access to this information. The methods and 
procedures described in this AC have evolved after many years and 
represents current certification practice.

    Issued in Renton, Washington, on November 30, 1998.
John J. Hickey,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service, ANM-100.
[FR Doc. 98-32967 Filed 12-10-98; 8:45 am]
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