[Federal Register Volume 70, Number 193 (Thursday, October 6, 2005)]
[Notices]
[Pages 58562-58563]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-19409]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration


Proposed Advisory Circular 25-YY, ``Development of Standard 
Wiring Practices Documentation''

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of availability and request for comments.

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SUMMARY: This notice announces the availability of and requests 
comments on a proposed advisory circular (AC) that sets forth 
acceptable methods of compliance with section H25.5(a)(2) of Appendix H 
to 14 CFR part 25 concerning development of an electrical system 
standard wiring practices document. This proposed AC complements 
revisions to the airworthiness standards that are being proposed by a 
separate notice. 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 December 5, 2005.

ADDRESSES: Send all comments on the proposed AC to: Federal Aviation 
Administration, Attention: Stephen Slotte, ANM-111, Airplane & Flight 
Crew Interface, Federal Aviation Administration, 1601 Lind Avenue SW., 
Renton, WA 98055-4056; telephone (425) 227-2315; facsimile (425) 227-
1320, e-mail <a href="/cdn-cgi/l/email-protection#aedddacbd8cb80ddc2c1dadacbeec8cfcf80c9c1d8"><span class="__cf_email__" data-cfemail="0477706172612a77686b707061446265652a636b72">[email protected]</span></a>. Comments may be inspected at the 
above address between 7:30 a.m. and 4 p.m. weekdays, except Federal 
holidays.

FOR FURTHER INFORMATION CONTACT: Annette Kovite, Transport Standards 
Staff, at the address above, telephone (425) 227-1262.

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 should identify AC 25-YY 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 FAA 
before issuing the final AC. The proposed AC can be found and 
downloaded from the Internet at http://www.airweb.faa.gov/rgl under 
``Draft Advisory Circulars.'' A paper copy of the proposed AC may be 
obtained by contacting the person named above under the caption FOR 
FURTHER INFORMATION CONTACT.

Discussion

    This proposed AC provides guidance for demonstrating compliance 
with the transport category airplane certification requirements of 
H25.5 Electrical Wiring Interconnection System (EWIS) Instructions for 
Continued Airworthiness. The guidance provided in this proposed AC is 
applicable to all air carriers, air operators, holders of type 
certificates, holders of STCs, maintenance providers, and repair 
stations operating under 14 CFR parts 21, 25, 43, 91, 121, 125, 135, 
and 145.
    This guidance is a product of the Aging Non-Structural Systems 
Plan. The FAA developed the Aging Non-Structural Systems Plan to 
address recommendations of the White House Commission on Aviation 
Safety and Security (WHCSS). That commission recommended that, in 
cooperation with airlines and manufacturers, the FAA's Aging Aircraft 
Program should be expanded to cover nonstructural systems.
    The commission was concerned that existing directives, procedures, 
quality assurance, and inspections may not be sufficient to prevent 
safety-related problems caused by corrosion and other deteriorating 
effects on nonstructural components of commercial aircraft as they age. 
To fully address the WHCSS recommendations on aging systems, we

[[Page 58563]]

formed an Aging Nonstructural Systems study team. This team, led by the 
Transport Airplane Directorate (TAD), conducted an inspection of 
systems in several aging airplanes. It then met with FAA principal 
maintenance inspectors (PMI) tasked with oversight of major air 
carriers to evaluate the need for additional work in addressing the 
commission's concerns. The team concluded that additional work was 
warranted and that industry involvement in this work was essential.
    The elements of the Aging Nonstructural Systems Plan were grouped 
into five major tasks. One task was to define standards for a 
simplified chapter 20, commonly referred to as the standard wiring 
practices manual (SWPM), of manufacturers' airplane maintenance 
manuals, and to define a process for training development based on the 
airline's customized chapter 20. This task was assigned to industry-
represented Task 4 Working Group.
    The tasking statement assigned to the Task 4 Working Group also 
required the group to consider ``simplification'' of chapter 20 of 
wiring diagram manuals (WDM). The working group concluded that 
simplification of the chapter 20 SWPM by end users was not appropriate 
for several reasons:
    1. It would not be practical, because end-users do not have access 
to the source data.
    2. It would result in different standards from one end-user to 
another.
    3. End-users would need the details for inspection, maintenance, 
and repair that are currently in the manufacturer's SWPM.
    At the conclusion of Aging Transport Non-Structural Systems Plan 
Phase I, the Task 4 Working Group stated that the current presentation 
and arrangement of standard wiring practices make it difficult for an 
aircraft maintenance technician to locate and extract pertinent and 
applicable data necessary to effect satisfactory electrical repairs.
    Subsequent tasks assigned to the Standard Wire Practice Manual 
Harmonization Working Group required the development of a standardized 
SWPM format and a definition of the minimum content to be included in 
an SWPM.
    This guidance presents one means, but not the only means, of 
complying with the part 25 revisions proposed in Notice No. 05-08, 
entitled ``Enhanced Airworthiness Program for Airplane Systems/Fuel 
Tank Safety (EAPAS/FTS),'' published in this same edition of the 
Federal Register. Issuance of AC 25-YY is contingent on final adoption 
of the proposed revisions to part 25.

    Issued in Washington, DC, on September 22, 2005.
John J. Hickey,
Director, Aircraft Certification Service.
[FR Doc. 05-19409 Filed 10-5-05; 8:45 am]
BILLING CODE 4910-13-P


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