Document ID: FAA-2009-0660-0001
Agency: faa
Document Type: Rule
Title: Damage Tolerance and Fatigue Evaluation of Composite Rotorcraft Structures
Posted Date: 2010-01-06T05:00Z

[Federal Register: January 6, 2010 (Volume 75, Number 3)]
[Proposed Rules]               
[Page 793-801]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr06ja10-16]                         

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Proposed Rules
                                                Federal Register
________________________________________________________________________

This section of the FEDERAL REGISTER contains notices to the public of 
the proposed issuance of rules and regulations. The purpose of these 
notices is to give interested persons an opportunity to participate in 
the rule making prior to the adoption of the final rules.

========================================================================

[[Page 793]]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Parts 27 and 29

[Docket No. FAA-2009-0660; Notice No. 09-12]
RIN 2120-AJ52

 
Damage Tolerance and Fatigue Evaluation of Composite Rotorcraft 
Structures

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This proposal would revise airworthiness standards for type 
certification requirements of normal and transport category rotorcraft. 
The amendment would require evaluation of fatigue and residual static 
strength of composite rotorcraft structures using a damage tolerance 
evaluation, or a fatigue evaluation, if the applicant establishes that 
a damage tolerance evaluation is impractical. The amendment would 
address advances in composite structures technology and provide 
internationally harmonized standards.

DATES: Send your comments on or before April 6, 2010

ADDRESSES: You may send comments identified by Docket Number FAA-2009-
0660 using any of the following methods:
     Federal eRulemaking Portal: Go to http://
www.regulations.gov and follow the online instructions for sending your 
comments electronically.
     Mail: Send comments to Docket Operations, M-30; U.S. 
Department of Transportation, 1200 New Jersey Avenue, SE., Room W12-
140, West Building Ground Floor, Washington, DC 20590-0001.
     Hand Delivery or Courier: Take comments to Docket 
Operations in Room W12-140 of the West Building Ground Floor at 1200 
New Jersey Avenue, SE., Washington, DC, between 9 a.m. and 5 p.m., 
Monday through Friday, except Federal holidays.
     Fax: Fax comments to Docket Operations at 202-493-2251.
    Privacy: We will post all comments we receive, without change, to 
http://www.regulations.gov, including any personal information you 
provide. Using the search function of our docket website, anyone can 
find and read the electronic form of all comments received into any of 
our dockets, including the name of the individual sending the comment 
(or signing the comment for an association, business, labor union, 
etc.). You may review DOT's complete Privacy Act Statement in the 
Federal Register published on April 11, 2000 (65 FR 19477-78) or you 
may visit http://DocketsInfo.dot.gov.
    Docket: To read documents or comments received, go to http://
www.regulations.gov and follow the online instructions for accessing 
the docket. Or, go to Docket Operations in Room W12-140 of the West 
Building Ground Floor at 1200 New Jersey Avenue, SE., Washington, DC, 
between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays.

FOR FURTHER INFORMATION CONTACT: For technical questions concerning 
this proposed rule contact Sharon Y. Miles, Regulations and Policy 
Group, Rotorcraft Directorate, ASW-111, Federal Aviation 
Administration, 2601 Meacham Boulevard, Fort Worth, Texas 76137-0111; 
telephone (817) 222-5122; facsimile (817) 222-5961; e-mail 
sharon.y.miles@faa.gov. For legal questions concerning this proposed 
rule contact Steve C. Harold, Directorate Counsel, ASW-7G1, Federal 
Aviation Administration, 2601 Meacham Boulevard, Fort Worth, Texas 
76137-0007, telephone (817) 222-5099; facsimile (817) 222-5945, e-mail 
steve.c.harold@faa.gov.

SUPPLEMENTARY INFORMATION: Later in this preamble under the Additional 
Information section, we discuss how you can comment on this proposal 
and how we will handle your comments. Included in this discussion is 
related information about the docket handling. We also discuss how you 
can get a copy of related rulemaking documents.

Authority for This Rulemaking

    The FAA's authority to issue rules on aviation safety is found in 
Title 49 of the United States Code. Subtitle I, Section 106 describes 
the authority of the FAA Administrator. Subtitle VII, Aviation 
Programs, describes in more detail the scope of the agency's authority.
    This rulemaking is issued under the authority described in Subtitle 
VII, Part A, Subpart III, Section 44701, ``General Requirements,'' 
Section 44702, ``Issuance of Certificates,'' and Section 44704, ``Type 
Certificates, Production Certificates, and Airworthiness 
Certificates.'' Under Section 44701, the FAA is charged with 
prescribing regulations and minimum standards for practices, methods, 
and procedures the Administrator finds necessary for safety in air 
commerce. Under Section 44702, the Administrator may issue various 
certificates including type certificates, production certificates, air 
agency certificates, and airworthiness certificates. Under Section 
44704, the Administrator must issue type certificates for aircraft, 
aircraft engines, propellers, and specified appliances when the 
Administrator finds the product is properly designed and manufactured, 
performs properly, and meets the regulations and minimum standards 
prescribed under section 44701(a). This regulation is within the scope 
of these authorities because it would promote safety by updating the 
existing minimum prescribed standards, used during the type 
certification process, to address advances in composite structural 
fatigue substantiation technology. It would also harmonize this 
standard with international standards for evaluating the fatigue 
strength of normal and transport category rotorcraft composite primary 
structural elements.

Background and Statement of the Issues

    The evolution of composite technology used in rotorcraft structures 
is advancing rapidly. These rapid changes with the increased use of 
composites in rotorcraft structures, issues discovered during 
certification of composite structures, and service experiences of 
composite rotorcraft structures over the last 25 years have caused us 
to reconsider the current regulations and guidance materials for damage 
tolerance and fatigue evaluation and to address the state of technology 
in composite structures. The current certification process is based on 
a broad interpretation of metallic fatigue

[[Page 794]]

substantiation and the design and construction airworthiness standards. 
However, composite and metal structures are different. Composites are 
complex materials that have unique advantages in fatigue strength, 
weight, and tolerance to damage. The methodologies for evaluating 
metallic structures are not necessarily suitable for composite 
structures. Since composite structures differ from metallic structures, 
the current regulations, Sec. Sec.  27.571 and 29.571, do not 
adequately provide the fatigue certification requirements for composite 
rotorcraft structures.
    This may lead to inconsistent interpretations from one rotorcraft 
certification project to another, resulting in different burdens on 
industry to substantiate their composite rotorcraft structures. It has 
also caused confusion for some certification applicants. These 
applicants state there is no clear, complete guidance for certification 
of composite rotorcraft structures.
    To address these concerns, the FAA tasked the Aviation Rulemaking 
Advisory Committee (ARAC) \1\ through its Composite Rotorcraft 
Structure working group to provide advice and recommendations as 
follows:
---------------------------------------------------------------------------

    \1\ Published in the Federal Register, April 5, 2000 (65 FR 
17936).
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     Recommend revisions to FAR/JAR 27 and 29 for composite 
structures that are harmonized.
     Evaluate and recommend, as appropriate, regulations, 
advisory material, and related guidance to achieve the goal of improved 
tolerance to flaws and defects in composite structure with methodology 
and procedures that are practical and appropriate to rotorcraft.
    This proposed rule is based on the ARAC's recommendations to the 
FAA. The recommendations have been placed in the docket for this 
rulemaking.

Related Activity

    At the same time the ARAC was tasked with providing advice and 
recommendations for composite rotorcraft structures, it was also tasked 
with providing advice and recommendations for metallic rotorcraft 
structures. Because of the unique characteristics and structural 
capabilities of composite structures, we believe a separate rule is 
needed for the damage tolerance and fatigue evaluations of rotorcraft 
composite structures. In response to the ARAC recommendations for 
improved standards for metallic structures, the FAA is developing an 
NPRM entitled Fatigue Tolerance Evaluation of Metallic Structures.

General Discussion of Proposals

    Composite structures present unique material behaviors and react 
differently than metallic to damage and loading conditions. This 
separate rulemaking action for the damage tolerance and fatigue 
evaluation of composite structures is proposed to address the type 
certification requirements for substantiating and certifying composite 
rotorcraft structures including different aspects of the evaluation for 
the most critical issues for each class of materials. These proposals 
address the unique characteristics of composite materials and would 
enable applicants to evaluate these types of materials in a different 
manner from those of the traditional metallic materials.
    The proposed changes would clarify the certification standards in 
areas of frequent non-standardization and misinterpretation. These 
proposals are intended to address fatigue damage tolerance conditions 
that can reduce structural strength. In composites, low cycle fatigue 
often yields minimal damage growth, whereas accidental damage from 
impact can immediately reduce residual structural strength. Conversely, 
in metals, any critical damage to the structure would be sensitive to 
cyclic fatigue loads.
    These proposals also address material and process variability and 
environmental effects. The FAA proposes a strength requirement for 
ultimate loads that would be applied when maximum acceptable 
manufacturing defects and service damage are present. These proposals 
would provide an exception to a damage tolerance evaluation if the 
applicant establishes impracticability and, in that instance, would 
allow a fatigue evaluation for some rotorcraft structures and damage 
scenarios based on retirement times instead of inspection intervals 
more commonly associated with damage tolerance standards. Under this 
proposal, an applicant could demonstrate that certain damage would not 
grow or does not grow beyond a certain threshold or size, and that the 
damaged structure could still carry ultimate loads. In this instance, 
an inspection may not be necessary and the structure could be assigned 
a retirement life instead of a required inspection program. Further, 
this proposal would require an applicant to conduct a threat 
assessment, which is associated with the service history of composite 
structures.
    The proposals consider varying types of damage, loading conditions, 
threat assessments, manufacturing defects, and residual strength 
associated with composite structures. In developing these proposals, we 
have recognized that it may be impractical within the limits of 
geometry, inspectability, or good design practice to evaluate all the 
composite structures of a rotorcraft using a damage tolerance 
evaluation. Therefore, this proposal allows for a fatigue evaluation of 
particular rotorcraft composite structures under Sec. Sec.  27.573(e) 
and 29.573(e) where appropriate, instead of requiring a damage 
tolerance evaluation for particular structures if the applicant can 
establish that an impracticability exists. As part of the approval 
process for fatigue evaluation of a particular rotorcraft composite 
structure, the applicant would be required to identify the Principal 
Structural Elements (PSEs) and the types of damage considered, 
establish supplemental procedures to minimize the risk of catastrophic 
failure associated with those types of damage, and include procedures 
in the Airworthiness Limitation section of the Instructions for 
Continued Airworthiness. The proposed requirements would minimize the 
risk of catastrophic failure of composite structures used on rotorcraft 
certificated in accordance with part 27 and part 29 standards.

Key Provisions in the New Rule

    Some of the proposed requirements for evaluating composite 
structures came from the current Sec.  29.571 standards. These 
requirements in the evaluation process include certain steps, such as 
identification of the PSEs, the in-flight measurements of loads, and 
the use of loading spectra as severe as those expected in-service. This 
proposal adds more detailed steps and does not refer to the current 
flaw tolerant safe-life and fail-safe evaluations because there are 
more suitable ways of describing each approach under damage tolerance. 
Further, these proposals do not refer to the traditional safe-life 
method because composites have sensitivities to defects and damage that 
must be considered in design and certification testing that make the 
traditional safe-life method inappropriate.
    These proposals would revise the standards for determining 
inspection intervals and retirement times based on results of damage 
tolerance and fatigue evaluation. Currently, the minimum residual 
structural strength requirement for any damage or defect that can be 
found by inspection is tied to limit loads (maximum loads to be 
expected in service). This proposal would link the required residual 
structural strength to

[[Page 795]]

the probability of a given damage type, inspection interval, and damage 
detectability. This link is necessary for at least two reasons. First, 
one of the more critical threats--impact damage--could immediately 
lower residual structural strength well below ultimate loads (limit 
loads multiplied by prescribed factors of safety) if it occurs. The 
proposal would ensure, as the residual structural strength is lowered, 
the earlier damage would be detected and repaired. Inspections would be 
required that would be frequent and comprehensive enough to reveal any 
damage or defect growth to minimize the time that the rotorcraft might 
be operated at less than an ultimate load capability. Second, this 
proposal would address rare damage (such as a high-energy, blunt 
impact) that is not detectable with the currently prescribed inspection 
schemes issued for aircraft in operational service. Although such 
damage may have a low probability of occurring, this proposal would 
require that sufficient residual structural strength exists to 
compensate for such damage.
    These proposals would require that all PSEs, the failure of which 
could result in catastrophic failure of the rotorcraft, meet ultimate 
load residual structural strength requirements or require that a 
retirement time be established if there could be any damage that may 
not be found by a maintenance inspection. Under this proposal, an 
applicant would establish a retirement time to assess the damage that 
may not be found by inspection or to eliminate the burden of the 
repeated inspections by the rotorcraft owners. For damage detectable by 
inspection, the proposal would establish a limit load requirement to 
repair and restore the structure to its ultimate strength capability.
    The FAA proposes to include all PSE assessments for damage threats, 
residual strength and fatigue characteristics to the list of 
requirements for inspection intervals or replacement times as stated in 
proposed Sec. Sec.  27.573(d)(1) and 29.573(d)(1). As a minimum, the 
fatigue evaluation would include the PSEs of the:

--Airframe,
--Main and tail rotor drive systems,
--Main and tail rotor blades and hubs,
--Rotor controls,
--Fixed and movable control surfaces,
--Engine and transmission mountings (provided by the airframe 
manufacturer), and
--Landing gear and other parts; as well as performing damage tolerance 
evaluations of the strength of composite:
--Detail design points and
--Fabrication techniques considered critical by the FAA to avoid 
catastrophic failure due to static or fatigue loads.

The proposal would require consideration of the effects of fatigue 
damage on stiffness, dynamic behavior, loads, and functional 
performance of composite structures. In the existing rule, such 
requirements are limited to fail-safe evaluations. These 
characteristics are not considered to be a serious threat to residual 
structural strength.
    The FAA recognizes there may be limited cases in which a damage 
tolerance evaluation may be impractical. In these rare cases, the 
applicant would be required to identify the nature of the evaluation 
and provide a justification to the FAA for the determination of its 
impracticality. The justification would support the specific types of 
damage to the PSE that would qualify for a fatigue evaluation. Finally, 
the proposal would require the applicant to establish replacement 
times, structural inspection intervals, and related structural 
inspection procedures to minimize the risk of catastrophic failure 
because of such damage. The required replacement times, inspection 
intervals, and structural inspections would be included in the 
Instructions for Continued Airworthiness as required by Sec. Sec.  
27.1529 and 29.1529.
    Additionally, the FAA recognizes that rare types of damage, such as 
high-energy, blunt impacts may not be uncovered as part of a base field 
inspection during scheduled maintenance inspection intervals. This 
proposal would require that the applicant substantiate sufficient 
residual structural strength to maintain an adequate level of safety in 
the event of an occurrence of rare damage. Supplemental procedures may 
be required to adequately address rare impact damage.

Airworthiness Limitations Section (Appendix A to Parts 27 and 29)

    This proposal would require the mandatory replacement times, 
structural inspection intervals, and related structural inspection 
procedures produced under the requirements of Sec. Sec.  27.571 and 
29.571, the new Sec. Sec.  27.573 and 29.573, and any other similar 
requirement for type certification be included in the Airworthiness 
Limitations Section of the Instructions for Continued Airworthiness.

Paperwork Reduction Act

    This proposal contains the following new information collection 
requirements. As required by 44 U.S.C. 3507(d) of the Paperwork 
Reduction Act of 1995, as implemented by 5 CFR part 1320, the FAA has 
submitted the information requirements associated with this proposal to 
the Office of Management and Budget (OMB) for review.
    Title: Damage Tolerance and Fatigue Evaluation of Composite 
Rotorcraft Structures.
    Summary: This proposal would add new certification standards for 
normal and transport category rotorcraft to address advances in 
structural damage tolerance and fatigue substantiation technology for 
composite rotorcraft structures. These proposals would increase the 
current minimum safety standards to require compliance with certain 
current industry practices and FAA policies that would result in higher 
safety standards, and would result in harmonized international 
standards. These proposals would help ensure that if damage occurs to 
composite structures during manufacturing or within the operational 
life of the rotorcraft, the remaining structure could withstand fatigue 
loads that are likely to occur, without failure, until the damage is 
detected. The damaged structure must then be repaired to restore 
ultimate load capability, or the part must be replaced. Proposed 
Sec. Sec.  27.573 and 29.573 would require that applicants get FAA 
approval of their proposed methods for complying with the certification 
requirements for damage tolerance and fatigue evaluation of composite 
structures.
    Use of information: The required damage tolerance and fatigue 
evaluation information would be determined for principal composite 
structural elements or components, detail design points, and 
fabrication techniques and would be collected from rotorcraft 
certification applicants. The FAA would use the approval process for 
the Applicant's submitted compliance methodology to determine whether 
the proposed methods were sufficient to comply with the certification 
requirements for damage tolerance and fatigue evaluation of composite 
structures. The FAA also would use the approval process for the 
Applicant's submitted compliance methodology to determine if the 
rotorcraft has any unsafe features in the composite structures.
    Respondents: The likely respondents to this proposed damage 
tolerance and fatigue evaluation information are applicants requesting 
type certification of composite structures. We anticipate about 10 
normal and transport category rotorcraft certification applicants 
(including supplemental type certificate

[[Page 796]]

applicants) over the 27-year analysis period or about 0.4 per year.
    Frequency: The frequency of determining the damage tolerance and 
fatigue evaluation methodologies would depend on how often an applicant 
seeks certification of a composite structure. This compliance 
methodology would be provided during each certification. We anticipate 
16.5 certifications over the 27 year analysis period or about 0.6 per 
year.
    Annual Burden Estimate: The compliance methodology would be 
required to be submitted and approved during each certification of a 
composite rotorcraft structure. We anticipate there would be 0.6 
certifications each year and it would take 182 hours to submit and 
approve the compliance methodology for each certification, for a total 
annual time burden of 109 hours. We anticipate that submitting and 
approving the compliance methodology for each certification would cost 
$100.00 per hour. Therefore, the estimated total annual cost burden 
would be $10,900.00.
    The agency is asking for comments to--
    (1) evaluate whether the proposed information requirement is 
necessary for the proper performance of the functions of the agency, 
including whether the information will have practical utility;
    (2) evaluate the accuracy of the agency's estimate of the burden;
    (3) improve the quality, utility, and clarity of the information to 
be collected; and
    (4) minimize the burden of collecting information on those who are 
to respond, by using appropriate automated, electronic, mechanical, or 
other technological collection techniques or other forms of information 
technology.
    Individuals and organizations may submit comments on the 
information collection requirement by March 8, 2010, and should direct 
them to the address listed in the ADDRESSES section. Comments also 
should be submitted to the Office of Management and Budget, Office of 
Information and Regulatory Affairs, Attention: Desk Officer for FAA, 
New Executive Building, Room 10202, 725 17th Street, NW., Washington, 
DC 20053.
    According to the 1995 amendments to the Paperwork Reduction Act and 
5 CFR 1320.8(b)(3)(vi), an agency may not collect or sponsor the 
collection of information, nor may it impose an information collection 
requirement unless it displays a currently valid OMB control number. 
The OMB control number for this information collection will be 
published in the Federal Register, after the Office of Management and 
Budget approval.

International Compatibility

    In keeping with U.S. obligations under the Convention on 
International Civil Aviation, it is FAA's policy to comply with 
International Civil Aviation Organization (ICAO) Standards to the 
maximum extent practicable. The FAA has determined that the proposed 
rule is consistent with the ICAO standard in ICAO Annex 8, Part IV.

European Aviation Safety Agency

    The European Aviation Safety Agency (EASA) was established by the 
European Community to develop standards to ensure safety and 
environmental protection, oversee uniform application of those 
standards, and promote them internationally. EASA formally became 
responsible for certification of aircraft, engines, parts, and 
appliances on September 28, 2003. The FAA and EASA are coordinating 
their rulemaking efforts to facilitate harmonized standards for 
evaluating the fatigue strength of composite rotorcraft structures.

Regulatory Evaluation, Regulatory Flexibility Determination, 
International Trade Impact Assessment, and Unfunded Mandates Assessment

    Changes to Federal regulations must undergo several economic 
analyses. First, Executive Order 12866 directs that each Federal agency 
shall propose or adopt a regulation only upon a reasoned determination 
that the benefits of the intended regulation justify its costs. Second, 
the Regulatory Flexibility Act of 1980 (Public Law 96-354) requires 
agencies to analyze the economic impact of regulatory changes on small 
entities. Third, the Trade Agreements Act (Pub. L. 96-39) prohibits 
agencies from setting standards that create unnecessary obstacles to 
the foreign commerce of the United States. In developing U.S. 
standards, this Trade Act requires agencies to consider international 
standards and, where appropriate, that they be the basis of U.S. 
standards. Fourth, the Unfunded Mandates Reform Act of 1995 (Pub. L. 
104-4) requires agencies to prepare a written assessment of the costs, 
benefits, and other effects of proposed or final rules that include a 
Federal mandate likely to result in the expenditure by State, local, or 
tribal governments, in the aggregate, or by the private sector, of $100 
million or more annually (adjusted for inflation with base year of 
1995). This portion of the preamble summarizes the FAA's analysis of 
the economic impacts of this proposed rule. We suggest readers seeking 
greater detail read the full regulatory evaluation, a copy of which we 
have placed in the docket for this rulemaking.
    In conducting these analyses, the FAA has determined that this 
proposed rule:
    (1) Has benefits that justify its costs;
    (2) Is not an economically ``significant regulatory action'' as 
defined in section 3(f) of Executive Order 12866;
    (3) Has been determined by the Office of Management and Budget to 
be a ``non-significant regulatory action;''
    (4) Is not ``significant'' as defined in DOT's Regulatory Policies 
and Procedures;
    (5) Would not have a significant economic impact on a substantial 
number of small entities;
    (6) Would not have a significant effect on international trade; and
    (7) Would not impose an unfunded mandate on State, local, or tribal 
governments by exceeding the monetary threshold identified.
    These analyses are summarized below.

Total Benefits and Costs of This Rulemaking

    The estimated total cost of this proposed rule is about $713,000 
($392,000 in present value, discounted at 7% for 27 years).
    Who is Potentially Affected by this Rulemaking?
     Manufacturers of U.S.-registered part 27 and part 29 
rotorcraft, and
     Operators of part 27 and part 29 rotorcraft.
    Our Cost Assumptions and Sources of Information.
     Discount rate--7%
     Period of analysis of 27 years equals the 27 years of 
National Transportation Safety Board accident history. During this 
period, manufacturers will seek new certifications for 10.5 part 27 
rotorcraft and six part 29 rotorcraft.
    This proposed rule consolidates FAA and industry past activities 
including special conditions, advisory circulars, and industry practice 
regarding the use of composites on rotorcraft. The benefits of this 
action exceed the small costs of this proposed rule.
    We estimate the costs of this proposed rule to be about $713,000 
($392,000 in present value) over the 27-year analysis period. 
Manufacturers of 14 CFR part 27 rotorcraft would incur costs of 
$101,000 ($55,000 in present value) and manufacturers of 14 CFR part 29 
helicopters would incur costs of $612,000 ($337,000 in present value).

Regulatory Flexibility Determination

    The Regulatory Flexibility Act of 1980 (RFA) establishes ``as a 
principle of

[[Page 797]]

regulatory issuance that agencies shall endeavor, consistent with the 
objective of the rule and of applicable statutes, to fit regulatory and 
informational requirements to the scale of the business, organizations, 
and governmental jurisdictions subject to regulation.'' To observe that 
principle, the RFA requires agencies to solicit and consider flexible 
regulatory proposals and to explain the rationale for their actions. 
The RFA covers a wide-range of small entities, including small 
businesses, not-for-profit organizations and small governmental 
jurisdictions.
    Agencies must perform a review to determine whether a proposed or 
final rule will have a significant economic impact on a substantial 
number of small entities. If the agency determines that it will, the 
agency must prepare a regulatory flexibility analysis as described in 
the Act.
    If an agency determines that a proposed or final rule is not 
expected to have a significant economic impact on a substantial number 
of small entities, section 605(b) of the 1980 RFA provides that the 
head of the agency may so certify, and a regulatory flexibility 
analysis is not required. The certification must include a statement 
providing the factual basis for this determination, and the reasoning 
should be clear.
    This proposed rule would affect rotorcraft manufacturers and 
rotorcraft operators. Therefore, the effect on potential small entities 
is analyzed separately for helicopter manufacturers and operators.

Part 27 Helicopter Manufacturers

Size Standards

    Size standards for small entities are published by the Small 
Business Administration (SBA) on their Web site at http://www.sba.gov/
size. The size standards used herein are from ``SBA U.S. Small Business 
Administration, Table of Small Business Size Standards, Matched to 
North American Industry Classification System Codes.'' The table is 
effective August 22, 2008 and uses the 2007 NAICS codes.
    Helicopter manufacturers are listed in the above-referenced table 
under Sector 31-33--Manufacturing; Subsector 336--Transportation 
Equipment Manufacturing; NAICS Code 336411--Aircraft Manufacturing. The 
small entity size standard is 1,500 employees.
    Table R1 shows there are six U.S. part 27 helicopter manufacturers 
that produce composite helicopters. MD Helicopters, with 400 employees, 
is the only part 27 helicopter manufacturer to qualify as a small 
entity. It is estimated that MD Helicopters has annual revenues of 
$175,000,000. The cost of this rule for one part 27 helicopter 
certification for a part 27 manufacturer is estimated to be $9,600 over 
27 years, and the total number of such certifications is estimated at 
10.5, if only one of these were performed by MD Helicopters, the cost 
would be equivalent to 0.005 percent of their total revenue, which 
would not represent a significant cost. Therefore, it is not 
anticipated that this proposed rule would have a significant economic 
impact on a substantial number of part 27 helicopter manufacturers.

                                                     Table R1--U.S. Part 27 Helicopter Manufacturers
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                                               Manufacturer                                                                    Annual
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                  Proposal
             Number                       Name           Ultimate owner     Employees      Small entity        Revenues (AR)     costs (PC)   % PC of AR
--------------------------------------------------------------------------------------------------------------------------------------------------------
1...............................  Agusta (A).........  Finmeccanica......       73,000  No................    [euro]15,037,000         N.A.         N.A.
2...............................  Bell Helicopter (B)  Textron...........       42,000  No................     $14,200,000,000         N.A.         N.A.
3...............................  Eurocopter (C).....  EADS..............      118,000  No................  [euro]43,3000,000,         N.A.         N.A.
                                                                                                                           000
4...............................  Kaman Aerospace (D)  Kaman Corp........        4,000  No................      $1,200,000,000         N.A.         N.A.
5...............................  MD Helicopters       None..............          400  Yes...............        $175,000,000       $9,600        0.01%
                                   (E)(F).
6...............................  Sikorsky (G).......  UTC...............      223,100  No................     $58,700,000,000         N.A.         N.A.
7...............................  Robinson             ..................  ...........  ..................  ..................  ...........  ...........
                                   Helicopters (H).
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Notes:
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(A) http://www.finmeccanica.com
(B) http://www.Textron.com/about/company
(C) http://www.eads.com
(D) http://www.kaman.com
(E) http://www.linkdin.com
(F) http://www.jigsaw.com/id55718/md_helicopters_company.xhtml (Average of range of $100-$250 million) Cost is based on one helicopter certifcation
 during the analysis period.
(G) http://www.utc.com/about_utc/fast_facts.Ihtml
(H) Robinson Helicopters is not included because it produces only metallic helicopters and is not expected to produce composite heliopters in the
 future..
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                                                                                                                                               8/10/2009
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Part 29 Helicopter Manufacturers

Size Standards

    Size standards for part 29 manufacturers are the same as the size 
standards for part 27 manufacturers.
    Table R2 shows there are four U.S. part 29 helicopter manufacturers 
currently producing helicopters. None of these manufacturers qualifies 
as a small entity. Therefore, it is not anticipated that this proposed 
rule would have a significant economic impact on a substantial number 
of part 29 helicopter manufacturers.

[[Page 798]]

                                                     Table R1--U.S. Part 29 Helicopter Manufacturers
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                                               Manufacturer                                                                    Annual
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                                                                                                                                  Proposal
             Number                       Name           Ultimate owner     Employees      Small entity        Revenues (AR)     costs (PC)   % PC of AR
--------------------------------------------------------------------------------------------------------------------------------------------------------
1...............................  Agusta (A).........  Finmeccanica......       73,000  No................    [euro]15,037,000         N.A.         N.A.
2...............................  Bell Helicopter (B)  Textron...........       42,000  No................     $14,200,000,000         N.A.         N.A.
3...............................  Eurocopter (C).....  EADS..............      118,000  No................  [euro]43,3000,000,         N.A.         N.A.
                                                                                                                           000
4...............................  Sikorsky (F).......  UTC...............      223,100  No................     $58,700,000,000         N.A.         N.A.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
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(A) http://www.finmeccanica.com
(B) http://www.Textron.com/about/company
(C) http://www.eads.com
(F) http://www.utc.com/about_utc/fast_facts.lhtml
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                                                                                                                                               8/10/2009
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Part 27 and Part 29 Helicopter Operators

Size Standards

    While there are only seven part 27 and four part 29 helicopter 
manufacturers in the United States, there are many small entities that 
are operators of part 27 and part 29 helicopters. Each of these 
operators may provide many services or only one. Such services include 
offshore transportation, executive transportation, fire-fighting, 
Emergency Medical Services (EMS), and training in maintenance, repair, 
and modification.
    The SBA lists small entity size standards for air transportation 
under Sector 44-45, Retail Trade, Subsector 481, Air Transportation. 
The small entity size standards are 1,500 employees for scheduled and 
nonscheduled charter passenger and freight transportation. This 
standard is $28.0 million annually if the passenger or freight air 
transportation is offshore marine air transportation. Finally, the 
small entity size standard for other--non-scheduled air transportation 
is $7.0 million annually.
    This proposed rule is not expected to increase the costs of part 27 
or part 29 helicopter operators, because we believe the helicopter 
inspection time for a composite part will be the same as or less than 
for a metallic part inspection. We request comments regarding this 
assumption.
    Consequently, the FAA certifies that this proposed rule would not 
have a significant economic impact on a substantial number of part 27 
or part 29 rotorcraft manufacturers or operators.

International Trade Impact Assessment

    The Trade Agreements Act of 1979 (Pub. L. 96-39), as amended by the 
Uruguay Round Agreements Act (Pub. L. 103-465), prohibits Federal 
agencies from establishing standards or engaging in related activities 
that create unnecessary obstacles to the foreign commerce of the United 
States. Pursuant to these Acts, establishing standards is not 
considered an unnecessary obstacle to the foreign commerce of the 
United States, so long as the standard has a legitimate domestic 
objective, such as the protection of safety, and does not operate in a 
manner that excludes imports that meet this objective. The statute also 
requires consideration of international standards and, where 
appropriate, that they be the basis for U.S. standards. The FAA has 
assessed the potential effect of this proposed rule and determined that 
it would impose the same costs on domestic and international entities 
and thus has a neutral trade impact.

Unfunded Mandates Assessment

    Title II of the Unfunded Mandates Reform Act of 1995 (Pub. L. 104-
4) requires each Federal agency to prepare a written statement 
assessing the effects of any Federal mandate in a proposed or final 
agency rule that may result in an expenditure of $100 million or more 
(adjusted annually for inflation) in any 1 year by state, local, and 
tribal governments, in the aggregate, or by the private sector; such a 
mandate is deemed to be a ``significant regulatory action.'' The FAA 
currently uses an inflation-adjusted threshold value of $141.3 million. 
This proposed rule does not contain such a mandate.

Executive Order 13132, Federalism

    The FAA has analyzed this proposed rule under the principles and 
criteria of Executive Order 13132, Federalism. We determined that this 
action would not have a substantial direct effect on the states, on the 
relationship between the national government and the states, or on the 
distribution of power and responsibilities among the various levels of 
government, and therefore, would not have federalism implications.

Regulations Affecting Intrastate Aviation in Alaska

    Section 1205 of the FAA Reauthorization Act of 1996 (110 Stat. 
3213) requires the Administrator, when modifying regulations in Title 
14 of the CFR in a manner affecting intrastate aviation in Alaska, to 
consider the extent to which Alaska is not served by transportation 
modes other than aviation, and to establish appropriate regulatory 
distinctions. Because this proposed rule would apply to the 
certification of future designs of rotorcraft and their subsequent 
operation, it could, if adopted, affect intrastate aviation in Alaska. 
The FAA, therefore, specifically requests comments on whether there is 
justification for applying the proposed rule differently in intrastate 
operations in Alaska.

Environmental Analysis

    FAA Order 1050.1E identifies FAA actions that are categorically 
excluded from preparation of an environmental assessment or 
environmental impact statement under the National Environmental Policy 
Act in the absence of extraordinary circumstances. The FAA has 
determined this proposed rulemaking action qualifies for the 
categorical exclusion identified in paragraph 312f and involves no 
extraordinary circumstances.

Regulations That Significantly Affect Energy Supply, Distribution, or 
Use

    The FAA has analyzed this NPRM under Executive Order 13211, Actions 
Concerning Regulations that Significantly Affect Energy Supply,

[[Page 799]]

Distribution, or Use (May 18, 2001). We have determined that it is not 
a ``significant regulatory action'' under the executive order because 
it is not likely to have a significant adverse effect on the supply, 
distribution, or use of energy.

Additional Information

    Comments Invited:
    The FAA invites interested persons to participate in this 
rulemaking by submitting written comments, data, or views. We also 
invite comments relating to the economic, environmental, energy, or 
federalism impacts that might result from adopting the proposals in 
this document. The most helpful comments reference a specific portion 
of the proposal, explain the reason for any recommended change, and 
include supporting data. To ensure the docket does not contain 
duplicate comments, please send only one copy of written comments, or 
if you are filing comments electronically, please submit your comments 
only one time.
    We will file in the docket all comments we receive, as well as a 
report summarizing each substantive public contact with FAA personnel 
concerning this proposed rulemaking. Before acting on this proposal, we 
will consider all comments we receive on or before the closing date for 
comments. We will consider comments filed after the comment period has 
closed if it is possible to do so without incurring expense or delay. 
We may change this proposal in light of the comments we receive.

Availability of Rulemaking Documents

    You can get an electronic copy of rulemaking documents using the 
Internet by--
    1. Searching the Federal eRulemaking Portal (http://
www.regulations.gov);
    2. Visiting the FAA's Regulations and Policies Web page at http://
www.faa.gov/regulations_policies/; or
    3. Accessing the Government Printing Office's Web page at http://
www.gpoaccess.gov/fr/index.html.
    You can also get a copy by sending a request to the Federal 
Aviation Administration, Office of Rulemaking, ARM-1, 800 Independence 
Avenue, SW., Washington, DC 20591, or by calling (202) 267-9680. Make 
sure to identify the docket number, notice number, or amendment number 
of this rulemaking.
    You may access all documents the FAA considered in developing this 
proposed rule, including economic analyses and technical reports, from 
the internet through the Federal eRulemaking Portal referenced in 
paragraph 1.

List of Subjects

14 CFR Part 27

    Aircraft, Aviation safety.

14 CFR Part 29

    Aircraft, Aviation safety.

The Proposed Amendment

    In consideration of the foregoing, the Federal Aviation 
Administration proposes to amend parts 27 and 29 of Title 14, Code of 
Federal Regulations, as follows:

PART 27--AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT

    1. The authority citation for part 27 continues to read as follows:

    Authority:  49 U.S.C. 106(g), 40113, 44701-44702, 44704.

    2. Add a new Sec.  27.573 to read as follows:

Sec.  27.573  Damage Tolerance and Fatigue Evaluation of Composite 
Rotorcraft Structures.

    (a) Each applicant must evaluate the composite rotorcraft structure 
under the damage tolerance standards of paragraph (d) of this section 
unless the applicant establishes that a damage tolerance evaluation is 
impractical within the limits of geometry, inspectability, and good 
design practice. If an applicant establishes that it is impractical 
within the limits of geometry, inspectability, and good design 
practice, the applicant must do a fatigue evaluation in accordance with 
paragraph (e) of this section.
    (b) The compliance methodology of each applicant, and the results 
of that methodology, requires FAA approval.
    (c) Definitions:
    (1) Catastrophic failure is an event that could prevent continued 
safe flight and landing.
    (2) Principal Structural Elements (PSEs) are structural elements 
that contribute significantly to the carrying of flight or ground 
loads, the failure of which could result in catastrophic failure of the 
rotorcraft.
    (3) Threat Assessment is an assessment that specifies the 
locations, types, and sizes of damage, considering fatigue, 
environmental effects, intrinsic and discrete flaws, and impact or 
other accidental damage (including the discrete source of the 
accidental damage) that may occur during manufacture or operation.
    (d) Damage Tolerance Evaluation:
    (1) Each applicant must show that catastrophic failure due to 
static and fatigue loads, considering the intrinsic or discrete 
manufacturing defects or accidental damage, is avoided throughout the 
operational life or prescribed inspection intervals of the rotorcraft 
by performing damage tolerance evaluations of the strength of composite 
PSEs and other parts, detail design points, and fabrication techniques. 
Each applicant must account for the effects of material and process 
variability along with environmental conditions in the strength and 
fatigue evaluations. Each applicant must evaluate parts that include 
PSEs of the airframe, main and tail rotor drive systems, main and tail 
rotor blades and hubs, rotor controls, fixed and movable control 
surfaces, engine and transmission mountings, landing gear and other 
parts, detail design points, and fabrication techniques deemed critical 
by the FAA. Each damage tolerance evaluation must include:
    (i) The identification of all PSEs;
    (ii) In-flight and ground measurements for determining the loads or 
stresses for all PSEs for all critical conditions throughout the range 
of limits in Sec.  27.309 (including altitude effects), except that 
maneuvering load factors need not exceed the maximum values expected in 
service;
    (iii) The loading spectra as severe as those expected in service 
based on loads or stresses determined under paragraph (d)(1)(ii) of 
this section, including external load operations, if applicable, and 
other operations including high-torque events;
    (iv) A threat assessment for all PSEs that specifies the locations, 
types, and sizes of damage, considering fatigue, environmental effects, 
intrinsic and discrete flaws, and impact or other accidental damage 
(including the discrete source of the accidental damage) that may occur 
during manufacture or operation; and
    (v) An assessment of the residual strength and fatigue 
characteristics of all PSEs that supports the replacement times and 
inspection intervals established under paragraph (d)(2) of this 
section.
    (2) Each applicant must establish replacement times, inspections, 
or other procedures for all PSEs to require the repair or replacement 
of damaged parts before a catastrophic failure. These replacement 
times, inspections, or other procedures must be included in the 
Airworthiness Limitations Section of the Instructions for Continued 
Airworthiness required by Sec.  27.1529.
    (i) Replacement times for PSEs must be determined by tests, or by 
analysis supported by tests, and must show that

[[Page 800]]

the structure is able to withstand the repeated loads of variable 
magnitude expected in-service. In establishing these replacement times, 
the following items must be considered:
    (A) Damage identified in the threat assessment required by 
paragraph (d)(1)(iv) of this section;
    (B) Maximum acceptable manufacturing defects and in-service damage 
(i.e., those that do not lower the residual strength below ultimate 
design loads and those that can be repaired to restore ultimate 
strength); and
    (C) Ultimate load strength capability after applying repeated 
loads.
    (ii) Inspection intervals for PSEs must be established to reveal 
any damage identified in the threat assessment required by paragraph 
(d)(1)(iv) of this section that may occur from fatigue or other in-
service causes before such damage has grown to the extent that the 
component cannot sustain the required residual strength capability. In 
establishing these inspection intervals, the following items must be 
considered:
    (A) The growth rate, including no-growth, of the damage under the 
repeated loads expected in-service determined by tests or analysis 
supported by tests;
    (B) The required residual strength for the assumed damage 
established after considering the damage type, inspection interval, 
detectability of damage, and the techniques adopted for damage 
detection. The minimum required residual strength is limit load; and
    (C) Whether the inspection will detect the damage growth before the 
minimum residual strength is reached and restored to ultimate load 
capability, or whether the component will require replacement.
    (3) Each applicant must consider the effects of damage on 
stiffness, dynamic behavior, loads, and functional performance on all 
PSEs in establishing the allowable damage size and inspection interval.
    (e) Fatigue Evaluation: If an applicant establishes that the damage 
tolerance evaluation described in paragraph (d) of this section is 
impractical within the limits of geometry, inspectability, or good 
design practice, the applicant must do a fatigue evaluation of the 
particular composite rotorcraft structure and:
    (1) Identify all PSEs considered in the fatigue evaluation;
    (2) Identify the types of damage for all PSEs considered in the 
fatigue evaluation;
    (3) Establish supplemental procedures to minimize the risk of 
catastrophic failure associated with the damages identified in 
paragraph (e) of this section; and
    (4) Include these supplemental procedures in the Airworthiness 
Limitations section of the Instructions for Continued Airworthiness 
required by Sec.  27.1529.

Appendix A to Part 27 [Amended]

    3. Amend the second sentence of section A.27.4 of Appendix A to 
Part 27 by removing the phrase ``approved under Sec.  27.571'' and 
adding the phrase ``required for type certification'' in its place.

PART 29--AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT

    4. The authority citation for part 29 continues to read as follows:

    Authority:  49 U.S.C. 106(g), 40113, 44701-44702, 44704.

    5. Add a new Sec.  29.573 to read as follows:

Sec.  29.573  Damage Tolerance and Fatigue Evaluation of Composite 
Rotorcraft Structures.

    (a) Each applicant must evaluate the composite rotorcraft structure 
under the damage tolerance standards of paragraphs (d) of this section 
unless the applicant establishes that a damage tolerance evaluation is 
impractical within the limits of geometry, inspectability, and good 
design practice. If an applicant establishes that it is impractical 
within the limits of geometry, inspectability, and good design 
practice, the applicant must do a fatigue evaluation in accordance with 
paragraph (e) of this section.
    (b) The compliance methodology of each applicant, and the results 
of that methodology, requires approval by the FAA.
    (c) Definitions:
    (1) Catastrophic failure is an event that could prevent continued 
safe flight and landing.
    (2) Principal Structural Elements (PSEs) are structural elements 
that contribute significantly to the carrying of flight or ground 
loads, the failure of which could result in catastrophic failure of the 
rotorcraft.
    (3) Threat Assessment is an assessment that specifies the 
locations, types, and sizes of damage, considering fatigue, 
environmental effects, intrinsic and discrete flaws, and impact or 
other accidental damage (including the discrete source of the 
accidental damage) that may occur during manufacture or operation.
    (d) Damage Tolerance Evaluation:
    (1) Each applicant must show that catastrophic failure due to 
static and fatigue loads, considering the intrinsic or discrete 
manufacturing defects or accidental damage, is avoided throughout the 
operational life or prescribed inspection intervals of the rotorcraft 
by performing damage tolerance evaluations of the strength of composite 
PSEs and other parts, detail design points, and fabrication techniques. 
Each applicant must account for the effects of material and process 
variability along with environmental conditions in the strength and 
fatigue evaluations. Each applicant must evaluate parts that include 
PSEs of the airframe, main and tail rotor drive systems, main and tail 
rotor blades and hubs, rotor controls, fixed and movable control 
surfaces, engine and transmission mountings, landing gear and other 
parts, detail design points, and fabrication techniques deemed critical 
by the FAA. Each damage tolerance evaluation must include:
    (i) The identification of all PSEs;
    (ii) In-flight and ground measurements for determining the loads or 
stresses for all PSEs for all critical conditions throughout the range 
of limits in Sec.  29.309 (including altitude effects), except that 
maneuvering load factors need not exceed the maximum values expected in 
service;
    (iii) The loading spectra as severe as those expected in service 
based on loads or stresses determined under paragraph (d)(1)(ii) of 
this section, including external load operations, if applicable, and 
other operations including high-torque events;
    (iv) A threat assessment for all PSEs that specifies the locations, 
types, and sizes of damage, considering fatigue, environmental effects, 
intrinsic and discrete flaws, and impact or other accidental damage 
(including the discrete source of the accidental damage) that may occur 
during manufacture or operation; and
    (v) An assessment of the residual strength and fatigue 
characteristics of all PSEs that supports the replacement times and 
inspection intervals established under paragraph (d)(2) of this 
section.
    (2) Each applicant must establish replacement times, inspections, 
or other procedures for all PSEs to require the repair or replacement 
of damaged parts before a catastrophic failure. These replacement 
times, inspections, or other procedures must be included in the 
Airworthiness Limitations Section of the Instructions for Continued 
Airworthiness required by Sec.  29.1529.
    (i) Replacement times for PSEs must be determined by tests, or by 
analysis supported by tests, and must show that the structure is able 
to withstand the repeated loads of variable magnitude expected in-
service. In establishing

[[Page 801]]

these replacement times, the following items must be considered:
    (A) Damage identified in the threat assessment required by 
paragraph (d)(1)(iv) of this section;
    (B) Maximum acceptable manufacturing defects and in-service damage 
(i.e., those that do not lower the residual strength below ultimate 
design loads and those that can be repaired to restore ultimate 
strength); and
    (C) Ultimate load strength capability after applying repeated 
loads.
    (ii) Inspection intervals for PSEs must be established to reveal 
any damage identified in the threat assessment required by paragraph 
(d)(1)(iv) of this section that may occur from fatigue or other in-
service causes before such damage has grown to the extent that the 
component cannot sustain the required residual strength capability. In 
establishing these inspection intervals, the following items must be 
considered:
    (A) The growth rate, including no-growth, of the damage under the 
repeated loads expected in-service determined by tests or analysis 
supported by tests;
    (B) The required residual strength for the assumed damage 
established after considering the damage type, inspection interval, 
detectability of damage, and the techniques adopted for damage 
detection. The minimum required residual strength is limit load; and
    (C) Whether the inspection will detect the damage growth before the 
minimum residual strength is reached and restored to ultimate load 
capability, or whether the component will require replacement.
    (3) Each applicant must consider the effects of damage on 
stiffness, dynamic behavior, loads, and functional performance on all 
PSEs in establishing the allowable damage size and inspection interval.
    (e) Fatigue Evaluation: If an applicant establishes that the damage 
tolerance evaluation described in paragraph (d) of this section is 
impractical within the limits of geometry, inspectability, or good 
design practice, the applicant must do a fatigue evaluation of the 
particular composite rotorcraft structure and:
    (1) Identify all PSEs considered in the fatigue evaluation;
    (2) Identify the types of damage for all PSEs considered in the 
fatigue evaluation;
    (3) Establish supplemental procedures to minimize the risk of 
catastrophic failure associated with the damages identified in 
paragraph (e) of this section; and
    (4) Include these supplemental procedures in the Airworthiness 
Limitations section of the Instructions for Continued Airworthiness 
required by Sec.  29.1529.

Appendix A to Part 29 [Amended]

    6. Amend the second sentence of section A.29.4 of Appendix A to 
Part 29 by removing the phrase ``approved under Sec.  29.571'' and 
adding the phrase ``required for type certification'' in its place.

    Issued in Washington, DC, on December 18, 2009.
K.C. Yanamura,
Acting Director, Aircraft Certification Service.

[FR Doc. E9-31381 Filed 1-5-10; 8:45 am]

BILLING CODE 4910-13-P