[Federal Register Volume 67, Number 113 (Wednesday, June 12, 2002)]
[Notices]
[Pages 40371-40372]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-14756]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration


Proposed Revision to Advisory Circular (AC) 25.981-1B, Fuel Tank 
Ignition Source Prevention Guidelines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed revision to advisory circular.

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SUMMARY: The Federal Aviation Administration invites public comment on 
a proposed revision to Advisory Circular 25.981-1B, Fuel Tank Ignition 
Source Prevention Guidelines. The revision provides updated guidelines 
for demonstrating compliance with the certification requirements for 
preventing ignition sources within the fuel tanks of transport category 
airplanes.

DATES: Comments must be received on or before September 10, 2002.

ADDRESSES: You should send your comments on the proposed revision to 
the Federal Aviation Administration, Attention: Mike Dostert, 
Propulsion/Mechanical Systems Branch, ANM-112, Transport Directorate, 
Aircraft Certification Service, 1601 Lind Ave SW., Renton, WA 98055-
4056. You may also submit comments electronically to: 
[email protected].

FOR FURTHER INFORMATION CONTACT: Mike Dostert at the above address, 
telephone (425) 227-2132, facsimile (425) 227-1320, or e-mail 
[email protected].

SUPPLEMENTARY INFORMATION:

How Do I Obtain a Copy of the Proposed Advisory Circular Revision?

    You may obtain an electronic copy of the draft advisory circular 
identified in this notice at the following Internet address: http://www.faa.gov/certification/aircraft/air_index.htm.
     Click on ``Advisory Circulars'';
     At the bottom of the next page, click on ``Related 
Links'';
     On the next page, click on ``Draft Advisory circulars''.
     On the next page, click on ``Open for Comment''.
    If you do not have access to the Internet, you may request a copy 
by contacting Mike Dostert at the address or phone number listed 
earlier in this announcement.

How Do I Submit Comments on the Draft Advisory Circular?

    You are invited to comment on the proposed advisory material by 
submitting written comments, data, or views. You must identify the 
title of the AC and submit your comments in duplicate to the address 
specified above. We will consider all comments received on or before 
the closing date for comments before issuing the final advisory 
material.

Discussion

    On May 7, 2002, the Federal Aviation Administration (FAA) published 
Amendment 25-102 to 14 CFR part 25 in the Federal Register (66 FR 
23086). That amendment requires design approval holders of certain 
turbine-powered transport category airplanes to submit substantiation 
to the FAA that the design of the fuel tank system of previously 
certificated airplanes precludes the existence of ignition sources 
within the airplane fuel tanks. The rule also requires the affected 
design approval holders to develop specific fuel tank system 
maintenance

[[Page 40372]]

and inspection instructions for any items in the fuel tank system that 
are determined to require repetitive inspections or maintenance, to 
assure the safety of the fuel tank system. In addition, the rule 
requires certain operators of those airplanes to incorporate FAA-
approved fuel tank system maintenance and inspection instructions into 
their current maintenance or inspection program.
    In addition to the rule changes adopted by amendment 25-102, the 
FAA also developed advisory material to supplement the rule changes. 
That advisory material was issued on April 18, 2001, as Advisory 
Circular (AC) 25.981-1B and AC 25.981-2. The FAA now announces the 
availability of a revised version of AC 25.981-1B for public comment.
    The revised advisory material, AC 25.981-1C, provides guidance on 
how to substantiate that ignition sources will not be present in 
airplane fuel tank systems following failures or malfunctions of 
airplane components or systems. Also included is guidance for 
developing any limitations for the Instructions for Continued 
Airworthiness that may be generated by the fuel tank system safety 
assessment identified in amendment 25-102.
    Since issuance of AC 25.981-1B, the FAA has received a number of 
comments and requests for additional guidance from users of the AC and 
has developed the revised AC to address these issues. Changes to the AC 
include:
     Clarification of the definition of filament heating energy 
levels,
     A new paragraph addressing electrostatics,
     A new paragraph describing considerations for establishing 
minimum wire separation distances,
     Discussion of use of silver inside fuel tanks,
     Additional guidance regarding spaces adjacent to fuel 
tanks
     New guidance on considerations for electrical bond 
redundancy, self bonding couplings, bond integrity checks, bond 
corrosion and integrity, and definition of major components.
    In addition, several portions of the AC have been reorganized to 
present the material in a more useable form. Revised text is 
highlighted in yellow for ease in identifying changes from the previous 
version (AC 25.981-1B). You may also review the previous version at the 
Internet address provided earlier in this document under the heading, 
``How do I obtain a copy of the proposed advisory circular revision?''

    Issued in Renton, Washington, on May 30, 2002.
Vi L. Lipski,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 02-14756 Filed 6-11-02; 8:45 am]
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