Fatigue Tolerance Evaluation of Metallic Structures, 11799-11806 [2010-5486]

Agencies

• Federal Aviation Administration
• DEPARTMENT OF TRANSPORTATION

[Federal Register Volume 75, Number 48 (Friday, March 12, 2010)]
[Proposed Rules]
[Pages 11799-11806]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2010-5486]


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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.

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Federal Register / Vol. 75, No. 48 / Friday, March 12, 2010 / 
Proposed Rules

[[Page 11799]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 29

[Docket No. FAA-2009-0413; Notice No. 10-04]
RIN 2120-AJ51


Fatigue Tolerance Evaluation of Metallic Structures

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: This proposed rule would amend the airworthiness standards for 
fatigue tolerance evaluation (FTE) of transport category rotorcraft 
metallic structures. This proposal would revise the FTE safety 
requirements to address advances in structural fatigue substantiation 
technology for metallic structures. This provides an increased level of 
safety by avoiding or reducing catastrophic fatigue failures of 
metallic structures. These increased safety requirements would help 
ensure that should serious accidental damage occur during manufacturing 
or within the operational life of the rotorcraft, the remaining 
structure could withstand, without failure, any fatigue loads that are 
likely to occur, until the damage is detected or the part is replaced. 
Besides improving the safety standards for FTE of all principal 
structural elements (PSEs), the proposed amendment would be harmonized 
with international standards.

DATES: Send your comments on or before June 10, 2010.

ADDRESSES: You may send comments identified by Docket Number FAA-2009-
0413 using any of the following methods:
     Federal eRulemaking Portal: Go to https://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: Bring 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: The FAA will post all comments we receive, without change, 
to https://www.regulations.gov, including any personal information you 
provide. Using the search function of the docket Web site, anyone can 
find and read the electronic form of all comments received into any of 
the 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 https://DocketsInfo.dot.gov.
    Docket: To read documents or comments received, go to https://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, Fort Worth, Texas 76137-0111; telephone number (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-7GI, Federal Aviation Administration, 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, there is a discussion of how you can comment on 
this proposal and how the FAA will handle your comments. Included in 
this discussion is related information about the docket handling. There 
is a discussion on 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 metallic structural 
fatigue substantiation technology. It would also harmonize this 
standard with international standards for evaluating the fatigue 
strength of transport category rotorcraft metallic primary structural 
elements.

Background

    Rotorcraft fatigue strength reduction or failure may occur because 
of aging, temperature, moisture absorption, impact damage, or other 
factors. Since a reduction in strength of any primary structural 
element can lead to a catastrophic failure, it is important to perform 
fatigue tolerance evaluations.
    Fatigue tolerance evaluation provides a strength assessment of 
primary

[[Page 11800]]

structural elements (PSEs). It requires the applicant to evaluate the 
strength of various rotorcraft components including, but not limited 
to, rotors, rotor drive systems between the engines and the main and 
tail rotor hubs, controls, fuselage, fixed and movable control 
surfaces, engine and transmission mountings, landing gear, and their 
related primary attachments. Fatigue tolerance evaluations of PSEs are 
performed to determine appropriate retirement lives and inspections to 
avoid catastrophic failure during the operational life of the 
rotorcraft.
    Advances in structural fatigue substantiation technology for 
metallic structures are not addressed in current regulations. The 
current regulations do not consider the advances in the safe-life 
methodology, and developments in crack growth methodology to address 
rotorcraft unique characteristics. This proposed rule would address 
those advances and amend the airworthiness standards for fatigue 
tolerance evaluation (FTE) of transport category rotorcraft metallic 
structures. This would increase the level of safety by avoiding or 
reducing catastrophic fatigue failures of metallic structures.

Fatigue Evaluation Techniques and Requirements

    In the 1950s, safe-life methodology to establish retirement lives, 
such as that described in AC 27-1B, MG 11, was used to evaluate the 
occurrence of fatigue conditions in rotorcraft dynamic components. 
Historically, application of this methodology has been successful in 
providing satisfactory reliability for transport category rotorcraft. 
In addition, manufacturers would include routine inspections in their 
maintenance programs to detect damage, such as scratches, corrosion, 
wear, or cracks. These inspections were not based on analysis or tests, 
but rather on experience with similar designs, engineering judgment, 
and good design practices. The inspections helped minimize the effect 
of damage when the rotorcraft was being operated.
    In the 1980s, industry recognized that a higher reliability for 
fatigue critical structural components might be achieved by considering 
the strength reducing effects of damage that can occur during 
manufacture or operation. About that same time, rotorcraft 
manufacturers were introducing advanced composite materials for fatigue 
critical components in their rotorcraft.
    The introduction of composites led manufacturers and regulatory 
authorities to develop a more robust safe-life methodology by 
considering the specific static and fatigue-strength reduction effects 
due to aging, temperature, moisture absorption, impact damage, and 
other accepted industry practices. Furthermore, where clearly visible 
damage resulted from impact or other sources, inspection programs were 
developed to maintain safety.
    With these developments, crack growth methodology has been 
successfully used for solving short-term airworthiness issues in 
metallic structures of rotorcraft and as the certification basis for 
civil and military transport aircraft applications. These advances in 
design, analytical methods, and other industry practices have made it 
feasible to address certain types of damage that could result in 
fatigue failure.
    Consistent with these technological advancements, the regulatory 
requirements of Sec.  29.571 were substantially revised by Amendment 
29-28 (54 FR 43930, October 27, 1989).
    While many years have passed since the introduction of these 
regulatory requirements, Amendment 29-28 has rarely been used for 
certification of completely new rotorcraft designs, because there have 
been only a limited number of new rotorcraft designs since 1989, when 
that amendment became effective. Even though there have been a limited 
number of new rotorcraft designs, the rotorcraft community's general 
understanding of rotorcraft fatigue tolerance evaluation has developed 
considerably. Also, there has been much discussion within the technical 
community about the meaning of Amendment 29-28 and the merits of its 
prescribed fatigue tolerance methodologies.
    These methodologies, discussed in Amendment 29-28, have been the 
subject of a series of meetings between the FAA, the rotorcraft 
industry, and the Technical Oversight Group for Aging Aircraft (TOGAA). 
These meetings and industry's position concerning rotorcraft fatigue 
and damage tolerance were documented in a White Paper, ``Rotorcraft 
Fatigue and Damage Tolerance,'' which is located in the docket (FAA-
2009-0413).
    The rotorcraft industry White Paper recommended that safe-life 
methods should be complemented by damage tolerance methods, but also 
recommended retention of the flaw tolerant safe-life method, introduced 
in Amendment 29-28, as an available option. However, in 1999, TOGAA 
recommended that current safe-life methods be complemented by damage 
tolerance assessment methods and that the flaw tolerant safe-life 
method be removed from the regulations. Since both groups recommended 
changes, the FAA decided to consider revision of the regulations.
    The FAA tasked the Aviation Rulemaking Advisory Committee (ARAC) in 
1991 to study the need to revise the regulations on fatigue evaluation 
in light of advancements in technology and operational procedures and 
to develop regulatory recommendations.

History of Aviation Rulemaking Advisory Committee (ARAC)

    The ARAC was established on February 5, 1991 by notice in the 
Federal Register (56 FR 2190, January 22, 1991), to assist the FAA in 
the rulemaking process by providing advice from the private sector on 
major regulatory issues affecting aviation safety. The ARAC includes 
representatives of manufacturers, air carriers, general aviation, 
industry associations, labor groups, universities, and the general 
public. The ARAC's formation has given the FAA added opportunities to 
seek information directly from significantly affected parties who meet 
and exchange ideas about proposed and existing rules that should be 
created, revised, or eliminated.
    Following an announcement in the Federal Register (65 FR 17936, 
April 5, 2000), the FAA chartered an ARAC Working Group to study and 
make appropriate recommendations on whether the FAA should issue new or 
revised airworthiness standards on fatigue evaluation of transport 
category rotorcraft metallic structures.
    The working group, co-chaired by representatives from a U.S. 
manufacturer and a European manufacturer, included technical 
specialists knowledgeable of fatigue evaluation of rotorcraft 
structures. This broad participation is consistent with FAA policy to 
have all known interested parties involved as early as practicable in 
the rulemaking process.
    The working group evaluated the industry White Paper, TOGAA's 
recommendations, and the continuing activities and results of 
rotorcraft damage tolerance research and development. Consequently, the 
working group recommended changes to the fatigue evaluation 
requirements for transport category rotorcraft found in 14 CFR 29.571 
to address advances in technology and damage tolerance assessment 
methodologies. The ARAC accepted those recommendations and presented 
them to the FAA. This proposed rule is consistent with the ARAC's 
recommendations.

[[Page 11801]]

Statement of the Issues

    Before Amendment 29-28, there was no requirement to assess the 
impact of damage on the fatigue performance of any rotorcraft 
structure. The strategy used to manage fatigue was limited to 
retirement of the rotorcraft part or component before the probability 
of crack initiation became significant, and the ``safe-life'' method 
was used to establish retirement times.
    It was generally agreed, based on in-service experience that not 
accounting for damage could be a serious shortcoming. Therefore, 
Amendment 29-28 required consideration of damage when performing 
fatigue evaluations unless it is established that for a particular 
structure damage consideration cannot be achieved within the 
limitations of geometry, inspectability, or good design practice. 
Amendment 29-28 also prescribed two new methods to account for damage 
(``flaw tolerant safe-life'' and ``fail-safe''). These are referred to 
as flaw tolerant methods. Amendment 29-28 also retained the original 
(``safe-life'') method to be used if either of the two new methods 
requiring damage consideration was not achievable within the 
limitations of geometry, inspectability, or good design practice.
    Within the context of current Sec.  29.571, the ``flaw tolerant 
safe-life'' method and the ``fail-safe'' method are considered 
equivalent options. The ``flaw tolerant safe-life'' method is based on 
crack initiation time in purposely ``flawed'' principal structural 
elements (PSEs) and results in a determination of retirement life. The 
flaw tolerant ``fail-safe'' method is based on a crack growth life in a 
purposely ``flawed'' PSE and results in inspection requirements.
    The ``safe-life'' method is based on a crack initiation time in a 
``non-flawed'' PSE and results in a retirement life. Although the 
``safe-life'' method does not explicitly account for any damage, under 
current Sec.  29.571, it is the prescribed default fatigue evaluation 
method if the applicant shows that neither of the flaw tolerant methods 
can be achieved within the limitations of geometry, inspectability, or 
good design practice.
    One of the primary issues addressed by the working group was the 
equivalency of the two flaw tolerant methods. While both can be used to 
address damage, their equivalency, from a technical perspective, is 
difficult to evaluate without specific factual details. To address this 
concern, the working group considered two issues, establishing 
inspection requirements using the flaw tolerant safe-life method, and 
establishing retirement times using the fail-safe method. While both 
are theoretically possible, an evaluation of the effectiveness is not 
possible without considering the details of a specific application. 
Additionally, while using the flaw tolerant safe-life method for 
establishing an inspection interval is clearly not within the intent of 
the Amendment 29-28, the fail-safe method for establishing retirement 
times has been accepted as meeting its intent.

Reference Material

    1. Industry White Paper ``Rotorcraft Fatigue and Damage 
Tolerance,'' prepared for the TOGAA, January 1999.
    2. TOGAA memo to the FAA, dated 15 March 1999.
    These reference materials are located in the regulatory docket.

Related Activity

    The FAA has initiated a separate proposal to address fatigue 
tolerance evaluation of composite structure. With the use of advanced 
composite materials for rotorcraft structural components, we determined 
that a separate requirement specific to composite structures is 
required to address the unique characteristics and structural 
capability of composite structures.

General Discussion of Proposals

    The proposed rule for rotorcraft metallic structure would revise 
and clarify fatigue evaluation requirements to facilitate an improved 
level of safety and reduce the occurrence of catastrophic fatigue 
failures of metallic structures. Some of the more significant proposed 
revisions to the current rule are summarized below.
    We have determined that the current rule is too prescriptive by 
directing the applicant to use specific methodologies to meet the 
safety objective. This approach has had the effect of lessening the 
significance of the basic objective of evaluating fatigue tolerance 
because in practice, the primary focus is on means of compliance. Thus, 
the entire rule has been rewritten to stress the performance objectives 
and deemphasize specific methodologies. We propose to delete all 
references to specific fatigue tolerance evaluation methods (i.e., flaw 
tolerant safe-life, fail-safe, and safe-life). The words ``flaw 
tolerant and fail-safe'' also have different meanings depending on 
usage. Rather, we propose a descriptive phrase that makes general 
reference to the entire fatigue evaluation process (including crack 
initiation, crack growth, and final failure) with or without the 
influence of damage. Consistent with the current rule, the phrase 
``fatigue tolerance'' is proposed for this purpose.
    There are various fatigue tolerance evaluation methods used by 
industry. All of these methods have merit and could potentially be 
effective, depending on the specifics of the damage being addressed. 
The proposed rule requires a specific result, but does not specify the 
method to achieve the result. However, the proposed rule does require 
that all methods be validated by testing, and the Administrator must 
approve the methodology used for compliance.
    We have determined that, in general, standards for the safest 
metallic structures use both retirement times and inspections together 
to mitigate the risk of catastrophic failure due to fatigue. 
Consequently, we propose a requirement in Sec.  29.571(h) to establish 
inspection and retirement times or an approved equivalent means that 
establish an increased level of safety for metallic structures.
    Also, we have determined that a key element that must be included 
in the evaluation is identification of all threats that need to be 
considered so damage to metallic structures can be quantified. 
Accordingly, paragraph (e)(4) of Sec.  29.571 requires a threat 
assessment for all identified PSEs.
    We recognize that an inspection approach may not be possible for 
some kinds of damage. Thus, we include a provision that would not 
require inspections, if they cannot be established within the 
limitations of geometry, inspectability, or good design practice. In 
this instance, other FAA approved procedures must be implemented to 
minimize the probability of the damage occurring or contributing to a 
catastrophic failure.

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, the FAA has submitted the information 
requirements associated with this proposal to the Office of Management 
and Budget for its review.
    Title: Fatigue Tolerance Evaluation (FTE) of Metallic Structures.
    Summary: This proposal would revise the FTE safety requirements to 
address advances in structural fatigue substantiation technology for 
metallic structures. An increased level of safety would be provided by 
avoiding or reducing catastrophic fatigue failures of metallic 
structures. These increased safety requirements would help ensure that 
should accidental damage occur during manufacturing or within the

[[Page 11802]]

operational life of the rotorcraft, the remaining structure could, 
without failure, withstand fatigue loads that are likely to occur until 
the damage is detected and repaired or the part is replaced. In 
addition to improving the safety standards for FTE of all PSE, the 
proposed amendment would lead to a harmonized international standard.
    Use of: To obtain type certification of a rotorcraft, an applicant 
must show that the rotorcraft complies with specific certification 
requirements. To show compliance, the applicant must submit 
substantiating data. FAA engineers or designated engineering 
representatives from industry would review the required data submittals 
to determine if the rotorcraft complies with the applicable minimum 
safety requirements for fatigue critical rotorcraft metallic structures 
and that the rotorcraft has no unsafe features in the metallic 
structures.
    Respondents (including number of): The likely respondents to this 
proposed information requirement are applicants for certification of 
fatigue critical metallic parts for transport category helicopters. A 
conservative estimate of the number of applicants affected by this rule 
would average 2 certification applicants every 10 years.
    Frequency: The frequency of collection of this information is 
established as needed by the respondent to meet their certification 
schedule. The respondent must submit the required information prior to 
type certification, which can span a number of years.
    Annual Burden Estimate: There will be 71.7 annual certification 
reporting and recordkeeping hours. The corresponding annual inspection 
hours are 197.1 (see table 12-1).
    The total annual certification reporting and recordkeeping hours 
are 7,167. The corresponding annual inspection costs are $11,827 (see 
table 13-1).

  Table 12-1--Estimated Hour Burden of Information Collection Reporting
                            and Recordkeeping
------------------------------------------------------------------------
                         Item                           Number of hours
------------------------------------------------------------------------
Certification Reporting and Recordkeeping Hours:       .................
    Reporting and Recordkeeping Hours Per                          322.5
     Certification...................................
    New Certifications...............................                6.0
    Total Certification Reporting and Recordkeeping              1,935.0
     Hours...........................................
Number of Years......................................               27.0
Annual Certification Reporting and Recordkeeping                    71.7
 Hours
Inspection Reporting and Recordkeeping Hours:
    Reporting and Recordkeeping Hours Per Inspection.                1.0
    Total Aircraft Inspections.......................            5,322.0
    Total Inspection Reporting and Recordkeeping                 5,322.0
     Hours...........................................
Number of Years......................................               27.0
Annual Inspection Reporting and Recordkeeping Hours..              197.1
------------------------------------------------------------------------


  Table 13-1--Estimated Hour Burden of Information Collection Reporting
                            and Recordkeeping
------------------------------------------------------------------------
                         Item                           Number of hours
------------------------------------------------------------------------
Certification Reporting and Recordkeeping Hours:
    Reporting and Recordkeeping Hours Per                          322.5
     Certification...................................
    New Certifications...............................                6.0
    Total Certification Reporting and Recordkeeping              1,935.0
     Hours...........................................
Unit Cost (Per Hour).................................               $100
    Total Certification Reporting and Recordkeeping             $193,500
     Costs...........................................
Number of Years......................................               27.0
Annual Certification Reporting and Recordkeeping                    71.7
 Hours...............................................
Annual Certification Reporting and Recordkeeping                  $7,167
 Costs...............................................
Inspection Reporting and Recordkeeping Hours:
    Reporting and Recordkeeping Hours Per Inspection.                1.0
    Total Aircraft Inspections.......................            5,322.0
    Total Inspection Reporting and Recordkeeping                 5,322.0
     Hours...........................................
Unit Cost (Per Inspection)...........................                $60
    Total Inspection Reporting and Recordkeeping                $319,320
     Costs...........................................
Number of Years......................................               27.0
Annual Inspection Reporting and Recordkeeping Hours..              197.1
Annual Inspection Reporting and Recordkeeping Costs..            $11,827
------------------------------------------------------------------------

    The agency is soliciting 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) enhance the quality, utility, and clarity of the information to 
be collected; and
    (4) minimize the burden of the collection of information on those 
who are to respond, including using appropriate automated, electronic, 
mechanical, or other technological collection techniques or other forms 
of information technology.
    Individuals and organizations may send comments on the information 
collection requirement by May 11, 2010, and should direct them to the 
address listed in the ADDRESSES section of this preamble. 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

[[Page 11803]]

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 approves it.

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 fatigue 
tolerance evaluation.

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 (Pub. L. 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, 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, however the Office of 
Management and Budget has determined that this NPRM is a ``significant 
regulatory action'' because it harmonizes U.S. aviation standards with 
those of other civil aviation authorities;
    (3) is ``significant'' as defined in DOT's Regulatory Policies and 
Procedures;
    (4) would have a non-significant economic impact on a substantial 
number of small entities;
    (5) would not have a significant effect on international trade; and
    (6) would not impose an unfunded mandate on State, local, or tribal 
governments, or on the private sector 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 $9.0 
million ($2.9 million in present value at 7% for 27 years). The 
estimated potential benefits of avoiding at least two of the 9 
avoidable historical transport category helicopter accidents are worth 
about $12.9 million ($5.6 million in present value).
Who Is Potentially Affected by This Rulemaking?
     Manufacturers of U.S.-registered part 29 rotorcraft, and
     Operators of 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 six part 29 
rotorcraft and the total new production helicopters are estimated to be 
about 1,300.
     Value of fatality avoided--$5.8 million (Source: U.S. 
Department of Transportation, Treatment of the Value of a Statistical 
Life in Department Analyses, February 5, 2008).

Benefits of This Rule

    The benefits of this proposed rule consist of the value of lives 
and property that would be saved due to avoiding accidents involving 
part 29 rotorcraft. Nine Transport Category rotorcraft accidents 
occurred over the past 27-year historical period. If this rule would 
have been in effect, it is expected that these nine accidents would 
have been averted. In the future, without this rule, it is expected 
that there would be another nine transport category helicopter 
accidents. The benefit of this proposed rule would be to avert some or 
all of these accidents. Even if only two of these accidents were to be 
prevented, the benefit would be approximately $12.9 million ($5.6 
million in present value).

Cost of This Rule

    We estimate the costs of this proposed rule to be about $9.0 
million ($2.9 million in present value) over the 27-year analysis 
period. Manufacturers of 14 CFR part 29 rotorcraft would incur costs of 
$532,000 ($293,000 in present value) and operators of 14 CFR part 29 
helicopters would incur costs of $8.5 million ($2.6 million in present 
value).

Regulatory Flexibility Determination

    The Regulatory Flexibility Act of 1980 (RFA) establishes ``as a 
principle of 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 achieve 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.
    However, 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

[[Page 11804]]

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 29 Helicopter Manufacturers

Size Standards

    Size standards for small entities are published by the Small 
Business Administration (SBA) on their Web site at https://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 NAICS 2007 NAICS codes.
    Helicopter manufacturers are listed in the above 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 the three U.S. part 29 helicopter manufacturers, 
Bell, Erickson Air Crane and Sikorsky. Erickson Air Crane, with 800 
employees, is the only part 29 helicopter manufacturer to qualify as a 
small entity. In addition, Erickson Air Crane currently specializes in 
the production of the S-64 Sky Crane and is not expected to obtain new 
helicopter certifications. Therefore, it is not anticipated that this 
proposed rule would have a significant economic impact on a substantial 
number of part 29 helicopter manufacturers.
[GRAPHIC] [TIFF OMITTED] TP12MR10.000

Part 29 Helicopter Operators

Size Standards

    While there are only three part 29 helicopter manufacturers in the 
United States, there are many operators of part 29 helicopters. Each of 
these operators may provide only one or many services. These services 
range from off-shore transportation, executive transportation, fire-
fighting services, Emergency Medical Services (EMS), and training to 
maintenance, repair, and modification services.
    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 of annual revenue if the passenger or freight 
air transportation is off-shore marine air transportation. Finally, the 
small entity size standard for other--non-scheduled air transportation 
is $7.0 million of annual revenue.
    PHI, Inc. is one of the largest helicopter operators in the world. 
According to PHI's 2007 Annual Report, in 2007 they employed 
approximately 2,254 full time employees and had annual revenues of 
$446.4 million.
    We have been unable to obtain the number of operators and the 
number of employees per operator. Therefore, we take the worst case 
scenario and assume that all operators would meet the SBA definition. 
Thus, this proposed rule would affect a substantial number of transport 
category helicopter operators.
    Based on the information received from industry representatives, 
the cost of this proposed rule to a part 29 helicopter operator would 
be $1,600 for an inspection that must be performed

[[Page 11805]]

every three years on each part 29 helicopter that is certificated under 
this proposed rule. This would be approximately $550 per helicopter per 
year. According to Bell Helicopter Product Specifications for the Bell 
430 (a part 29 helicopter), January 2005, the direct operating cost of 
one flight hour is $671.44. Therefore, the proposed rule would add less 
than one direct hour of operating costs per year to a typical part 29 
helicopter. Although this would be an increase in costs, it is not 
considered that this would be a substantial increase in costs.
    Consequently, the FAA certifies that this proposed rule would not 
have a significant economic impact on a substantial number of 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, the establishment of 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 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 value of $136.1 million in lieu of 
$100 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 have 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 (49 U.S.C. 
40113(f)) requires the Administrator, when modifying regulations in 
Title 14 of the CFR in any manner affecting interstate aviation in 
Alaska, to consider the extent to which Alaska is not served by 
transportation modes other than aviation, and to establish any 
appropriate regulatory distinctions. Because this proposed rule would 
apply to the certification of future designs of transport category 
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, 
Distribution, or Use (May 18, 2001). We have determined that it is not 
a ``significant energy action'' under the executive order because while 
it is a ``significant regulatory action,'' 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.
    The FAA 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 additional expense 
or delay. The FAA may change this proposal in light of the comments we 
receive.

Availability of Rulemaking Documents

    You may obtain an electronic copy of rulemaking documents using the 
Internet by--
    1. Searching the Federal eRulemaking Portal (https://www.regulations.gov);
    2. Visiting the FAA's Regulations and Policies Web page at https://www.faa.gov/regulations_policies/; or
    3. Accessing the Government Printing Office's Web page at https://www.gpoaccess.gov/fr/.
    You may also obtain 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 or notice 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 in 14 CFR Part 29

    Aircraft, Aviation safety.

The Proposed Amendment

    In consideration of the foregoing, the Federal Aviation 
Administration proposes to amend Chapter I of Title 14, Code of Federal 
Regulations, as follows:

[[Page 11806]]

PART 29--AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT

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

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

    2. Revise Sec.  29.571 to read as follows:


Sec.  29.571  Fatigue Tolerance Evaluation of Metallic Structure.

    (a) A fatigue tolerance evaluation of each principal structural 
element (PSE) must be performed, and appropriate inspections and 
retirement time or approved equivalent means must be established to 
avoid catastrophic failure during the operational life of the 
rotorcraft. The fatigue tolerance evaluation must consider the effects 
of both fatigue and the damage determined in paragraph (e)(4) of this 
section. Parts to be evaluated include PSEs of the rotors, rotor drive 
systems between the engines and rotor hubs, controls, fuselage, fixed 
and movable control surfaces, engine and transmission mountings, 
landing gear, and their related primary attachments.
    (b) For the purposes of this section, the term--
    Catastrophic failure means an event that could prevent continued 
safe flight and landing.
    Principal Structural Element (PSE) means a structural element that 
contributes significantly to the carriage of flight or ground loads, 
and the fatigue failure of that structural element could result in 
catastrophic failure of the aircraft.
    (c) The methodology used to establish compliance with this section 
must be submitted and approved by the Administrator.
    (d) Considering all rotorcraft structure, structural elements, and 
assemblies, each PSE must be identified.
    (e) Each fatigue tolerance evaluation required by this section must 
include:
    (1) In-flight measurements to determine the fatigue loads or 
stresses for the PSEs identified in paragraph (d) of this section in 
all critical conditions throughout the range of design limitations 
required in Sec.  29.309 (including altitude effects), except that 
maneuvering load factors need not exceed the maximum values expected in 
operations.
    (2) The loading spectra as severe as those expected in operations 
based on loads or stresses determined under paragraph (e)(1) of this 
section, including external load operations, if applicable, and other 
high frequency power-cycle operations.
    (3) Takeoff, landing, and taxi loads when evaluating the landing 
gear and other affected PSEs.
    (4) For each PSE identified in paragraph (d) of this section, a 
threat assessment which includes a determination of the probable 
locations, types, and sizes of damage, taking into account fatigue, 
environmental effects, intrinsic and discrete flaws, or accidental 
damage that may occur during manufacture or operation.
    (5) A determination of the fatigue tolerance characteristics for 
the PSE with the damage identified in paragraph (e)(4) of this section 
that supports the inspection and retirement times, or other approved 
equivalent means.
    (6) Analyses supported by test evidence and, if available, service 
experience.
    (f) A residual strength determination is required to establish the 
allowable damage size. In determining inspection intervals based on 
damage growth, the residual strength evaluation must show that the 
remaining structure, after damage growth, is able to withstand design 
limit loads without failure within its operational life.
    (g) The effect of damage on stiffness, dynamic behavior, loads, and 
functional performance must be considered.
    (h) Based on the requirements of this section, inspections and 
retirement times or approved equivalent means must be established to 
avoid catastrophic failure. The inspections and retirement times or 
approved equivalent means must be included in the Airworthiness 
Limitations Section of the Instructions for Continued Airworthiness 
required by Section 29.1529 and Section A29.4 of Appendix A of this 
part.
    (i) If inspections for any of the damage types identified in 
paragraph (e)(4) of this section cannot be established within the 
limitations of geometry, inspectability, or good design practice, then 
supplemental procedures, in conjunction with the PSE retirement time, 
must be established to minimize the risk of occurrence of these types 
of damage that could result in a catastrophic failure during the 
operational life of the rotorcraft.

    Issued in Washington, DC, on March 7, 2010.
Kalene C. Yanamura,
Acting Director, Aircraft Certification Service.
[FR Doc. 2010-5486 Filed 3-11-10; 8:45 am]
BILLING CODE 4910-13-P