[Federal Register Volume 80, Number 16 (Monday, January 26, 2015)]
[Notices]
[Pages 4029-4032]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2015-01044]


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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 new task assignment for the Aviation Rulemaking 
Advisory Committee (ARAC).

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SUMMARY: The FAA assigned the Aviation Rulemaking Advisory Committee 
(ARAC) a new task to provide recommendations regarding revision of the 
damage-tolerance and fatigue requirements of Title 14, Code of Federal 
Regulations (14 CFR), part 25, including subparts C and E of 14 CFR 
part 26, and development of associated advisory material for metallic, 
composite, and hybrid structures. Past changes to the damage-tolerance 
and fatigue airworthiness standards and advisory material have been 
more specific to transport airplanes constructed predominantly of 
metal, using skin-stringer-frame architecture. Today, the trend in 
industry is to use more composite and hybrid structures (i.e., 
structure that includes a combination of composite and metallic parts 
and assemblies) to improve the performance of transport airplanes. As a 
result, the damage-tolerance and fatigue airworthiness standards and 
advisory

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material may not be adequate to address this trend. This notice informs 
the public of the new ARAC activity and solicits membership for the new 
Transport Airplane Metallic and Composite Structures Working Group.

FOR FURTHER INFORMATION CONTACT: Walt Sippel, Federal Aviation 
Administration, 1601 Lind Avenue SW., Renton, WA 98057-3356, 
[email protected], phone number 425-227-2774, facsimile number 425-
227-1232.

SUPPLEMENTARY INFORMATION: 

ARAC Acceptance of Task

    As a result of the December 18, 2014, ARAC meeting, the FAA has 
assigned and ARAC has accepted this task establishing the Transport 
Airplane Metallic and Composite Structures Working Group, under the 
Transport Airplane and Engine (TAE) Subcommittee. The working group 
will serve as staff to the ARAC and provide advice and recommendations 
on the assigned task. The ARAC will review and approve the 
recommendation report and will submit it to the FAA.

Background

    The FAA established the ARAC to provide information, advice, and 
recommendations on aviation related issues that could result in 
rulemaking to the FAA Administrator, through the Associate 
Administrator of Aviation Safety.
    The Transport Airplane Metallic and Composite Structures Working 
Group will provide advice and recommendations to the ARAC on the 
damage-tolerance and fatigue requirements of part 25 and any associated 
advisory material for metallic, composite, and hybrid structures. This 
includes the requirements of and regulatory guidance material for 
subparts C and E of part 26 and any associated advisory material.
    The requirements of Sec.  25.571 apply equally to structure 
constructed from either metallic or nonmetallic materials. Guidance 
material is contained in the Federal Aviation Administration (FAA) 
Advisory Circulars (AC) 25.571-1D and 20-107B for metallic and 
composite structures, respectively. The changes to Sec.  25.571 that 
the FAA has adopted over the years have been more specific to the 
technical issues primarily associated with metallic structure. In 
Amendment 25-132 to Sec.  25.571, the FAA added requirements for 
applicants to establish a limit of validity of the engineering data 
that supports the structural maintenance program (hereafter referred to 
as LOV) and to demonstrate that widespread fatigue damage (WFD) will 
not occur in the airplane prior to reaching the LOV. The objective of 
this change, along with the development of the related guidance 
material, was focused on addressing the normal fatigue wear-out of 
metallic structure. Among other things, Sec.  25.571 requires 
applicants to establish an LOV based on WFD considerations, and 
identify in the structural-maintenance program all maintenance actions 
required to address fatigue, environmental damage, and accidental 
damage throughout the operational life of the airplane. In a similar 
way, subpart C requires certain actions to prevent catastrophic failure 
due to WFD throughout the operational life of certain existing 
transport category airplanes. The FAA also adopted subpart E of part 26 
to require holders of design approvals to make available to operators 
damage tolerance data for repairs and alterations to fatigue critical 
airplane structure. In addition to AC 25.571-1D, guidance material for 
subparts C and E of part 26 are contained in ACs 120-104 and 120-93, 
respectively. Because the adoption of those requirements and Sec.  
25.571 were primarily focused on metallic structure, the FAA needs to 
evaluate those rules and advisory material to determine whether further 
changes are required to address composite structures.

Remaining Rulemaking Recommendations

    In 1995, the FAA tasked the ARAC to recommend appropriate revisions 
for harmonization of Sec.  25.571, supporting policy and guidance 
material, and corresponding paragraph 25.571 of the Joint Aviation 
Requirements (JAR), which is now Certification Specification (CS) 
25.571 under the European Aviation Safety Agency (EASA). The ARAC 
formed the General Structures Harmonization Working Group (GSHWG) to 
carry out that task. In 2003, the GSHWG submitted the Working Group 
Report on Sec.  25.571 and JAR 25.571 [CS 25.571] to ARAC. That report 
described proposed changes to harmonize the rules and related guidance 
material. The GSHWG recommended revising or adding requirements for 
inspection thresholds, LOV, and structural damage capability.
    Subpart C of part 26 and Sec.  25.571, Amendment 25-132, 
incorporated the recommendation to add requirements for establishing an 
LOV. The FAA has not yet addressed the GSHWG recommendations related to 
inspection thresholds and structural damage capability, and would 
request these be considered in the context of this rulemaking, which 
include:
     Replacing the prescriptive requirement of Sec.  
25.571(a)(3) for setting damage-tolerance inspection thresholds with a 
performance-based requirement.
     Adding a requirement for showing structural capability in 
the presence of damage, so that even if the structure fails partially, 
there will still be enough structure remaining to be safe.

Increased Use of Composites

    Today, the trend in industry is to use more composite structures 
than in the past. The Small Airplane and Rotorcraft Directorates 
addressed this trend by creating separate rules for parts 23, 27 and 29 
for composite structures (Sec.  2X.573). This tasking will consider the 
changes to those rules as part of the evaluation of the damage-
tolerance and fatigue airworthiness standards and associated advisory 
material.
    In June of 2009, the FAA Transport Airplane Directorate sought 
comments through the Federal Register (74 FR 26919) on a need for 
future rulemaking to address extensive use of composite materials in 
transport category airplane construction. Several candidate technical 
areas were noted in the request, including fire safety, 
crashworthiness, lightning protection, fuel tank safety and damage-
tolerance. The response by industry indicated that each area needs 
improved guidance and possible rulemaking. We believe the damage-
tolerance requirements would require relatively small changes versus 
some of the updates desired in other areas.
    Composite considerations the working group will need to address 
include:
     Composite analyses and test protocols as related to 
evolving industry practices and the development of regulatory 
standards.
     Composite damage threats (e.g., environmental and 
accidental damage) and associated maintenance practices.
     Large-scale test demonstration of repeated-load 
reliability and a need to use load enhancement factors for composite 
structure.
     Thermal stresses generated between metal-composite 
interfaces, which are difficult to replicate in structural repeated-
load testing but are required by Sec.  25.571 to be considered.

Future Applicability

    Any future change to Sec.  25.571 should be performance-based to 
the extent possible, allowing application to not only current aerospace 
materials and material systems, but those yet to be developed (i.e., 
emerging technology). Guidance material, including changes to AC 
25.571-1D, or AC 20-107B, should provide complete guidance for

[[Page 4031]]

traditional metal structure, composite structure, and hybrid structure 
(i.e., structures that include a combination of composite and metallic 
parts and assemblies).
    There are other FAA initiatives in the area of transport 
crashworthiness, fuel tank lightning protection, and composite 
flammability testing, which will lead to further standardization of 
requirements related to composite airframes. These initiatives would 
not affect Sec.  25.571.

The Task

    The Transport Airplane Metallic and Composite Structures Working 
Group is tasked to:
    1. Evaluate Sec.  25.571, subparts C and E of part 26, and 
associated regulatory guidance material (e.g., advisory circulars and 
policy statements) to determine whether any changes to the 
airworthiness standards and/or guidance material are required to 
address transport airplanes being constructed of metallic, composite, 
and hybrid structures. The working group is also tasked to evaluate 
whether any changes to part 25 and the associated regulatory guidance 
material are required to provide consistency with the damage-tolerance 
and fatigue airworthiness standards and associated guidance material 
for parts 23, 27, and 29. The working group is requested to include in 
its evaluation a review of the following advisory circulars (AC) and 
policy statements (PS):
    a. Advisory Circulars: AC 25.571-1, Damage Tolerance and Fatigue 
Evaluation of Structure; AC 20-107, Composite Airframe Structure; AC 
120-93, Damage Tolerance Inspections for Repairs and Alterations; AC 
120-104, Establishing and Implementing Limit of Validity to Prevent 
Widespread Fatigue Damage; AC 27-1, Certification of Normal Category 
Rotorcraft (specifically, Subpart C--Strength Requirements); and AC 29-
2, Certification of Transport Category Rotorcraft (specifically, 
Subpart C--Strength Requirements).
    b. Policy Statements: PS-ANM100-1989-00048, Policy Regarding Impact 
of Modifications and Repairs on the Damage Tolerance Characteristics of 
Transport Category Airplanes; PS-ACE100-2001-006, Static Strength 
Substantiation of Composite Airplane Structure; PS-AIR-100-120-07, 
Guidance for Component Contractor Generated Composite Design Values for 
Composite Structure; PS-ACE100-2002-006, Material Qualification and 
Equivalency for Polymer Matrix Composite Material Systems; PS-ANM-100-
1991-00049, Policy Regarding Material Strength Properties and Design 
Values, Sec.  25.613; PS-ANM100-1993, Compliance with Sec.  25.571(e) 
Discrete Source Damage (Uncontained Engine Failure).
    2. Advise and make written recommendations on whether to change 14 
CFR part 25, subparts C and E of 14 CFR part 26, and related regulatory 
guidance material, such as ACs 25.571-1, 20-107, 120-93, and 120-104, 
to address the use of metallic, composite, and hybrid structures in 
transport airplanes. In developing the recommendations, the working 
group is requested to consider:
    a. The threats associated with fatigue, environmental exposure, and 
accidental damage that must be addressed per Sec.  25.571.
    b. Applicability to emerging technology materials.
    c. The recommendations contained in the 2003 General Structures 
Harmonization Working Group (GSHWG) report entitled, ``Damage Tolerance 
and Fatigue Evaluation of Structures, FAR/JAR Sec.  25.571.'' You can 
find the GSHWG report at http://www.faa.gov/regulations_policies/rulemaking/committees/documents/index.cfm/document/information/documentID/384. The working group recommendations should include 
whether it is appropriate to:
    i. Require applicants to assume the structure contains an initial 
flaw of the maximum probable size that could exist as a result of 
manufacturing or service-induced damage.
    ii. Add a requirement for showing structural capability in the 
presence of damage, so that even if the structure fails partially, 
there will still be enough structure remaining to be safe.
    d. The continued operational safety of composite and hybrid 
structures as they age, including any airworthiness limitations in the 
structural maintenance program.
    e. The testing of hybrid structure, including, but not limited to, 
addressing thermal effects, test duration, load enhancement factors, 
and crack-growth retardation.
    f. The bonding or bolting of repairs to metallic, composite, and 
hybrid structures.
    g. The certification of large structural modifications on transport 
airplanes constructed of composite or hybrid structures.
    h. The EASA rulemaking activity on aging aircraft for harmonization 
purposes.
    3. Provide recommendations on appropriate performance-based 
requirements to address the results of the evaluations above, with 
consideration of applicability not only to metals and known composites, 
but also other emerging technology materials.
    4. Provide recommendations on any new guidance or changes to 
existing guidance, including AC 25.571-1D, and AC 20-107B to address 
the results of the evaluations above.
    5. Provide initial qualitative and quantitative costs and benefits. 
Based on the recommendations, perform the following:
    a. Estimate the costs to implement the recommendations;
    b. Estimate the benefits of the recommendations in terms of 
potential fatalities averted;
    c. Estimate any other benefits (e.g., reduced administrative 
burden) that would result from implementation of the recommendations.
    6. Develop a report containing recommendations on the findings and 
results of the tasks explained above.
    a. The recommendation report should document both majority and 
dissenting positions on the findings and the rationale for each 
position.
    b. Any disagreements should be documented, including the rationale 
for each position and the reasons for the disagreement.
    7. The working group may be reinstated to assist the ARAC by 
responding to the FAA's questions or concerns after the recommendation 
report has been submitted.

Schedule

    The recommendation report must be submitted to the FAA for review 
and acceptance no later than 24 months after publication of this 
notice.

Working Group Activity

    The Transport Airplane Metallic and Composite Structures Working 
Group must comply with the procedures adopted by the ARAC. As part of 
the procedures, the working group must:
    1. Conduct a review and analysis of the assigned tasks and any 
other related materials or documents.
    2. Draft and submit a work plan for completion of the task, 
including the rationale supporting such a plan, for consideration by 
the Transport Airplane and Engine Subcommittee.
    3. Provide a status report at each Transport Airplane and Engine 
Subcommittee meeting.
    4. Draft and submit the recommendation report based on the review 
and analysis of the assigned tasks.
    5. Present the recommendation report at the Transport Airplane and 
Engine Subcommittee meeting.

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    6. Present the findings from the additional tasks at the Transport 
Airplane and Engine Subcommittee meeting.
    7. Present the findings in response to the FAA's questions or 
concerns about the recommendation report at the Transport Airplane and 
Engine Subcommittee meeting.

Participation in the Working Group

    The Transport Airplane Metallic and Composite Structures Working 
Group will be comprised of technical experts having an interest in the 
assigned task. A working group member need not be a member 
representative of the ARAC. The FAA would like a wide range of members 
to ensure all aspects of the tasks are considered in development of the 
recommendations. The provisions of the August 13, 2014, Office of 
Management and Budget guidance, ``Revised Guidance on Appointment of 
Lobbyists to Federal Advisory Committees, Boards, and Commissions'' (79 
FR 47482), continues the ban on registered lobbyists participating on 
Agency Boards and Commissions if participating in their ``individual 
capacity.'' The revised guidance now allows registered lobbyists to 
participate on Agency Boards and Commissions in a ``representative 
capacity'' for the ``express purpose of providing a committee with the 
views of a nongovernmental entity, a recognizable group of persons or 
nongovernmental entities (an industry, sector, labor unions, or 
environmental groups, etc.) or state or local government.'' (For 
further information see Lobbying Disclosure Act of 1995 (LDA) as 
amended, 2 U.S.C 1603, 1604, and 1605.)
    If you wish to become a member of the Transport Airplane Metallic 
and Composite Structures Working Group, write the person listed under 
the caption FOR FURTHER INFORMATION CONTACT expressing that desire. 
Describe your interest in the task and state the expertise you would 
bring to the working group. The FAA must receive all requests by 
February 25, 2015. The ARAC and the FAA will review the requests and 
advise you whether or not your request is approved.
    If you are chosen for membership on the working group, you must 
actively participate in the working group by attending all meetings, 
and providing written comments when requested to do so. You must devote 
the resources necessary to support the working group in meeting any 
assigned deadlines. You must keep your management chain and those you 
may represent advised of working group activities and decisions to 
ensure the proposed technical solutions do not conflict with the 
position of those you represent. Once the working group has begun 
deliberations, members will not be added or substituted without the 
approval of the Transport Airplane and Engine Subcommittee Chair, the 
FAA, including the Designated Federal Officer, and the Working Group 
Chair.
    The Secretary of Transportation determined the formation and use of 
the ARAC is necessary and in the public interest in connection with the 
performance of duties imposed on the FAA by law.
    ARAC meetings are open to the public. However, meetings of the 
Transport Airplane Metallic and Composite Structures Working Group are 
not open to the public, except to the extent individuals with an 
interest and expertise are selected to participate. The FAA will make 
no public announcement of working group meetings.

    Issued in Washington, DC, on January 16, 2015.
Lirio Liu,
Designated Federal Officer, Aviation Rulemaking Advisory Committee.
[FR Doc. 2015-01044 Filed 1-23-15; 8:45 am]
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