[Federal Register Volume 65, Number 136 (Friday, July 14, 2000)]
[Notices]
[Pages 43800-43802]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-17860]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration


Aviation Rulemaking Advisory Committee--New Task

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of a new task assignment for the Aviation Rulemaking 
Advisory Committee (ARAC).

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SUMMARY: Notice is given of a new task assigned to and accepted by the 
Aviation Rulemaking Advisory Committee (ARAC). This notice informs the 
public of the activities of ARAC.

FOR FURTHER INFORMATION CONTACT: Anthony F. Fazio, Director, Office of 
Rulemaking, ARM-1, Federal Aviation Administration, 800 Independence 
Avenue, SW., Washington, DC 20591; telephone (202) 267-9677 or fax 
(202) 267-5075.

SUPPLEMENTARY INFORMATION:  

Background

    The FAA has established an Aviation Rulemaking Advisory Committee 
to provide advice and recommendations to the FAA Administrator, through 
the Associate Administrator for Regulation and Certification, on the 
full range of the FAA's rulemaking activities with respect to aviation-
related issues. This includes obtaining advice and recommendations on 
the FAA's commitment to harmonize its Federal Aviation Regulations and 
practices with Europe and Canada.

The Task

    This notice is to inform the public that the FAA has asked ARAC to 
provide advice and recommendation on the following harmonization task:
    The ARAC Executive Committee will establish a Fuel Tank Inerting 
Harmonization Working Group. The Fuel Tank Inerting Harmonization 
Working Group will prepare a report to the FAA that provides 
recommended regulatory text for new rulemaking and the data needed for 
the FAA to evaluate the options for implementing new regulations that 
would require eliminating or significantly reducing the development of 
flammable vapors in fuel tanks on in-service, new production, and new 
type design transport category airplanes. The level of reduction in 
flammable vapors that would be proposed in this FAA rulemaking would be 
based on achieving the lowest flammability level that could be provided 
by a design that would meet FAA regulatory evaluation requirements. 
This effort is an extension of the previous work performed by the Fuel 
Tank Harmonization Working Group.
    The report should contain a detailed discussion of the technical 
issues associated with the prevention of, or reduction in, the exposure 
of fuel tanks to a flammable environment through the use of the 
following inerting design methods, and any other inerting methods 
determined by the Working Group, or its individual members, to merit 
consideration.
    Ground-Based Inerting: The system shall inert fuel tanks that are 
located near significant heat sources or do not cool at a rate 
equivalent to an unheated wing tank using ground based nitrogen gas 
supply equipment. The affected fuel tanks shall be inerted once the 
airplane reaches the gate and while the airplane is on the ground 
between flights.
    On-Board Ground-Inerting: The system shall inert fuel tanks that 
are located near significant heat sources or are not cooled at a rate 
equivalent to an unheated wing tank using on-board nitrogen gas 
generating equipment. The affected fuel tanks shall be inerted while 
the airplane is on the ground between flights.
    On-Board Inert Gas Generating System (OBIGGS): The system shall 
inert all fuel tanks with an on-board nitrogen gas generating system 
such that the tanks remain inert during normal ground and typical 
flight operations. Non-normal operations are not to be included in the 
OBIGGS mission requirements. For example, the tanks should remain inert 
during normal takeoff, climb, cruise, descent, landing, and ground 
operations (except for ground maintenance operations when the fuel tank 
must be purged for maintenance access); however, the fuel tanks do not 
need to remain inert during non-normal operations such as during an 
emergency descent.

[[Page 43801]]

    For the purposes of this task, an ``unheated wing tank'' is a 
conventional aluminum structure, integral tank of a subsonic transport 
wing, with minimum heat input from aircraft systems or other fuel tanks 
that are heated. This is the same definition provided in draft Advisory 
Circular 25.981-2X that was made available for comment by the notice 
published in the Federal Register on February 2, 2000.
    The report shall provide detailed discussion of technical 
considerations (both pro and con), as well as comparisons between each 
of the above design methods for incorporation into the following 
portion of the large transport airplane fleet: (a) In-service 
airplanes, (b) new production airplanes, and (c) new airplane designs. 
Because the working group may consist of members having differing views 
regarding the technical issues associated with inerting fuel tanks, the 
report should include discussion of such views and any supporting 
information provided by the membership.
    In developing recommendations to the FAA, the report should also 
include consideration of the following:
    1. The threat of fuel tank explosions used in the analysis should 
include explosions due to internal and external tank ignition sources 
for the major fuel system designs making up the transport fleet, as 
defined in the July 1998 ARAC Fuel Tank Harmonization Working Group 
report. The service history in the analysis should be further developed 
to include incidents involving post crash fuel tank fires. The FAA 
awarded a research contract to develop a database that may be useful in 
this endeavor. This data should be evaluated when determining what 
benefits may be derived from implementing ground based or on-board 
inerting systems. The report is titled, A Benefit Analysis for Nitrogen 
Inerting of Aircraft Fuel Tanks Against Ground Fire Explosion, Report 
Number DOT/FAA/AR-99/73, dated December 1999.
    2. The evaluation of ground-based inerting should consider:
    a. The benefits and risks of limiting inerting of fuel tanks to 
only those times when conditions, such as lower fuel quantities or 
higher temperature days, could create flammable vapors in the fuel 
tank. This concept would be analogous to deicing of aircraft when icing 
conditions exist.
    b. Various means of supplying nitrogen (e.g., liquid, gaseous 
separation technology; centralized plant and/or storage with pipeline 
distribution system to each gate, individual trucks to supply each 
airplane after refueling, individual separation systems at each gate, 
etc.), and which means would be most effective at supplying the 
quantity of nitrogen needed at various airports within the United 
States and, separately, other areas of the world.
    c. Methods of introducing the nitrogen gas into the affected fuel 
tanks that should be considered include displacing the oxygen in fuel 
tanks with nitrogen gas, saturating the fuel with nitrogen in ground 
storage facilities (for example, in the trucks or central storage 
tanks), injecting nitrogen directly into the fuel as the fuel is loaded 
onto the airplane, and combinations of methods.
    d. The benefits and risks of limiting inerting of fuel tanks to 
only those fuel tanks located near significant heat sources, such as 
center wing tanks located above air conditioning packs.
    3. The evaluation of on-board ground-inerting should consider the 
benefits and risks of limiting inerting of fuel tanks to only those 
fuel tanks located near significant heat sources, such as center wing 
tanks located above air conditioning packs.
    4. The evaluation of the cost of an OBIGGS for application to new 
type designs should assume that the design can be optimized in the 
initial airplane design phase to minimize the initial and recurring 
costs of a system.
    5. Evaluations of all systems should include consideration of 
methods to minimize the cost of the system. For example, reliable 
designs with little or no redundancy should be considered, together 
with recommendations for dispatch relief authorization using the master 
minimum equipment list (MMEL) in the event of a system failure or 
malfunction that prevents inerting one or more affected fuel tanks.
    6. Information regarding the secondary effects of utilizing these 
systems (e.g., increased extracted engine power, engine bleed air 
supply, maintenance impact, airplane operational performance 
detriments, dispatch reliability, etc.) must be analyzed and provided 
in the report.
    7. In the event that the working group does not recommend 
implementing any of the approaches described in this tasking statement, 
the team must identify all technical limitations for that system and 
provide an estimate of the type of improvement in the concept (i.e., 
manufacturing, installation, operation and maintenance cost reduction, 
etc.; and/or additional safety benefit required) that would be required 
to make it practical in the future.
    8. In addition, guidance is sought that will describe analysis and/
or testing that should be conducted for certification of all systems 
recommended.
    Unless the working group produces data that demonstrates otherwise, 
for the purposes of this study a fuel tank is considered inert when the 
oxygen content of the ullage (vapor space) is less than ten per cent by 
volume.
    The ground-based inerting systems shall provide sufficient nitrogen 
to inert the affected fuel tanks while the airplanes are on the ground 
after landing and before taking off for the following flight. In 
addition to the ground equipment requirements and airframe 
modifications required for the nitrogen distribution system, any 
airframe modifications required to keep the fuel tank inert during 
ground operations, takeoff, climb, and cruise, until the fuel tank 
temperatures fall below the lower flammability range, should be 
defined.
    The on-board ground inerting systems shall be capable of inerting 
the affected fuel tanks while the airplane is on the ground after 
touchdown and before taking off for the following flight. As for the 
ground-based inerting system, in addition to the inert gas supply 
equipment and distribution system, any airframe modifications required 
to keep the fuel tank inert during ground operations, takeoff, climb, 
and cruise, until the time the fuel tank temperatures fall below the 
lower flammability range, should be defined. Consideration should be 
given to operating the on-board inert gas generating system during some 
phases of flight as an option to installing equipment that might 
otherwise be necessary (e.g., vent system valves) to keep the fuel tank 
inert during those phases of flight, and as a cost tradeoff that could 
result in reduced equipment size requirements.
    The data in the report will be used by the FAA in evaluating if a 
practical means of inerting fuel tanks can be found for the in-service 
fleet, new production airplanes, and new airplane designs. The FAA may 
propose regulations to further require reducing the level of 
flammability in fuel tanks if studies, including this ARAC task and 
independent FAA research and development programs, indicate that a 
means to significantly reduce or eliminate the flammable environment in 
fuel tanks, beyond that already proposed in Notice 99-18, is practical. 
Such a proposal would be consistent with the recommendations made by 
the ARAC Fuel Tank Harmonization Working Group in their July 1998 
report.
    The report shall be submitted to the FAA within 12 months after the 
date of this notice.

[[Page 43802]]

ARAC Acceptance of Task

    ARAC has accepted this task and has chosen to assign it to a new 
Fuel Tank Inerting Harmonization Working Group. The new working group 
will serve as staff to the ARAC Executive Committee to assist ARAC in 
the analysis of the assigned task. Working group recommendations must 
be reviewed and approved by ARAC. If ARAC accepts the working group's 
recommendations, it will forward them to the FAA as ARAC 
recommendations.
    The Fuel Tank Inerting Harmonization Working Group should 
coordinate with other harmonization working groups, organizations, and 
specialists as appropriate. The working group will identify to ARAC the 
need for additional new working groups when existing groups do not have 
the appropriate expertise to address certain tasks.

Working Group Activity

    The Fuel Tank Inerting Harmonization Working Group is expected to 
comply with the procedures adopted by ARAC. As part of the procedures, 
the working group is expected to:
    1. Recommend a work plan for completion of the task, including the 
rationale supporting such a plan, for consideration at the ARAC 
Executive Committee meeting held following the establishment and 
selection of the working group.
    2. Give a detailed conceptual presentation of the proposed 
recommendations, prior to proceeding with the work stated in item 3 
below.
    3. Draft a report and/or any other collateral documents the working 
group determines to be appropriate.
    4. Provide a status report at each meeting of the ARAC Executive 
Committee.

Participation in the Working Group

    The Fuel Tank Inerting Harmonization Working Group will be composed 
of experts having an interest in the assigned task. Participants of the 
working group should be prepared to devote a significant portion of 
their time to the ARAC task for a 12-month period. A working group 
member need not be a representative or a member of the committee.
    An individual who has expertise in the subject matter and wishes to 
become a member of the working group should contact: Regina L. Jones, 
ARM-23, Office of Rulemaking, Federal Aviation Administration, 800 
Independence Avenue, SW., Washington, DC 20591; telephone (202) 267-
9822, fax (202) 267-5075, or e-mail [email protected], expressing 
that desire, describing his or her interest in the tasks, and stating 
the expertise he or she would bring to the working group. All requests 
to participate must be received no later than August 11, 2000. The 
requests will be reviewed by the ARAC chair, the executive director, 
and the working group chair, and the individuals will be advised 
whether or not requests can be accommodated.
    The Secretary of Transportation has determined that the formation 
and use of ARAC are necessary and in the public interest in connection 
with the performance of duties imposed on the FAA by law.
    Meetings of the ARAC Executive Committee will be open to the 
public. Meetings of the Fuel Tank Inerting Harmonization Working Group 
will not be open to the public, except to the extent that individuals 
with an interest and expertise are selected to participate. No public 
announcement of working group meetings will be made.

    Issued in Washington, DC, on July 10, 2000.
Anthony F. Fazio,
Executive Director, Aviation Rulemaking Advisory Committee.
[FR Doc. 00-17860 Filed 7-11-00; 2:12 pm]
BILLING CODE 4910-13-M