Fatigue Tolerance Evaluation of Metallic Structures, 75435-75442 [2011-30941]

Agencies

• Federal Aviation Administration
• DEPARTMENT OF TRANSPORTATION

[Federal Register Volume 76, Number 232 (Friday, December 2, 2011)]
[Rules and Regulations]
[Pages 75435-75442]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-30941]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 29

[Docket No. FAA-2009-0413; Amdt. No. 29-55]
RIN 2120-AJ51


Fatigue Tolerance Evaluation of Metallic Structures

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: This rule amends the airworthiness standards for fatigue 
tolerance evaluation (FTE) of transport category rotorcraft metallic 
structures. This revises 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 the likelihood of the catastrophic fatigue failure of a 
metallic structure. These increased safety requirements will 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 amendment is harmonized with 
international standards.

DATES: Effective January 31, 2012.

ADDRESSES: For information on where to obtain copies of rulemaking 
documents and other information related to this final rule, see ``How 
To Obtain Additional Information'' at the end of the SUPPLEMENTARY 
INFORMATION section of this document.

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

SUPPLEMENTARY INFORMATION:

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 will promote the safety of transport 
category rotorcraft metallic structures by updating the existing 
minimum prescribed standards, used during the type certification 
process, to address advances in metallic structural fatigue 
substantiation technology. It will also harmonize this standard with 
international standards for evaluating the fatigue strength of 
transport category rotorcraft metallic primary structural elements.

I. Overview of Final Rule

    This rule for rotorcraft metallic structures revises fatigue 
evaluation requirements to improve safety and reduce the occurrence of 
catastrophic fatigue failures of metallic structures. Some of the more 
significant revisions 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 deleted all references to 
specific FTE methods (that is, flaw tolerant safe-life, fail-safe, and 
safe-life). The words ``flaw tolerant'' and ``fail-safe'' have 
different meanings depending on usage. Instead, we now use ``fatigue 
tolerance'' which encompasses the entire fatigue evaluation process 
(including crack initiation, crack growth, and final failure) with or 
without the influence of damage.
    Industry currently uses a variety of FTE methods; all of these 
methods have merit and could potentially be effective, depending on the 
specifics of the damage being addressed. To reflect this flexibility, 
the amended rule requires a specific result (that is, inspection, 
retirement times, or equivalent means to avoid catastrophic failure), 
but does not specify the method to achieve this result. However, this 
rule does require that all methods be validated by testing, and that 
the Administrator must approve the methodology used for compliance.
    We have determined that, in general, standards for the safest 
metallic structures use both inspections and

[[Page 75436]]

retirement times together to mitigate the risk of catastrophic failure 
due to fatigue. Consequently, Sec.  29.571(h) requires inspections and 
retirement times or approved equivalent means to be established to 
avoid catastrophic failure, resulting in an increased level of safety 
for metallic structures.
    Also, we added a key element to the FTE: the identification of all 
threats that need to be considered to quantify damage to metallic 
structures. 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 effective inspections 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.
    The following table contains an overview of the costs and benefits 
associated with the rule.

                               Table 1--Present Value Benefits and Costs--27 Years
----------------------------------------------------------------------------------------------------------------
          Benefits (27 years) accidents  averted
-----------------------------------------------------------       Costs        Benifits minus     Revised rule
                                               $Value        (millions) (27   costs (27 years)    effectiveness
                 Number                      (millions)          years)                             (percent)
----------------------------------------------------------------------------------------------------------------
2.......................................              $5.6              $2.9              $2.7                22
5.......................................              14.1               2.9              11.2                56
9.......................................              25.4               2.9              22.5               100
----------------------------------------------------------------------------------------------------------------

03/16/2011

II. Background

    Rotorcraft fatigue strength reduction or failure may occur due to 
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 evaluate 
fatigue tolerance.
    A FTE provides a strength assessment of 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. A FTE of PSEs is performed 
to determine the appropriate required inspections and retirement times 
to avoid catastrophic failure during the operational life of the 
rotorcraft.
    The current regulations do not address advances in structural 
fatigue substantiation technology for metallic structures (for example, 
advances in the safe-life methodology, and developments in crack growth 
methodology) required for the unique characteristics of a rotorcraft. 
This rule addresses those advances and amends the airworthiness 
standards for FTE of transport category rotorcraft metallic structures.

Fatigue Evaluation Techniques and Requirements

    In the 1950s, safe-life methodology, such as described in AC 27-1B, 
MG 11, was used to evaluate the occurrence of fatigue conditions in 
rotorcraft dynamic components to establish retirement times. 
Historically, this methodology has provided satisfactory reliability 
for transport category rotorcraft. In addition, manufacturers included 
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 may 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 factors. 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 used 
successfully for solving short-term airworthiness issues in metallic 
structures of rotorcraft and in the certification of civil and military 
transport aircraft. 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). Although Amendment 29-28 became 
effective in 1989, it has rarely been used for certification of 
completely new rotorcraft designs because there have been only a 
limited number of new rotorcraft designs since it was adopted. However, 
despite the limited opportunity for actual application of Amendment 29-
28, the rotorcraft community's general understanding of rotorcraft FTE 
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 the industry's position concerning rotorcraft 
fatigue and damage tolerance were documented in a White Paper, 
``Rotorcraft Fatigue and Damage Tolerance.''
    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

[[Page 75437]]

the flaw tolerant safe-life method be removed from the regulations. 
Because both groups recommended various methods of evaluating fatigue, 
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 advances in technology and operational procedures and to 
develop regulatory recommendations.
    The ARAC working group for this rule 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. ARAC accepted those recommendations and 
presented them to the FAA. This rule is consistent with ARAC's 
recommendations.
    The Industry White Paper ``Rotorcraft Fatigue and Damage 
Tolerance,'' prepared for the TOGAA, January 1999, and the TOGAA memo 
to the FAA, dated 15 March 1999, are located in the docket.

A. Statement of the Problem

    Before current 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 requires the applicant to consider damage when 
performing fatigue evaluations unless it establishes that, for a 
particular structure, damage evaluation cannot be achieved within the 
limitations of geometry, inspectability, or good design practice. 
Amendment 29-28 prescribes two new methods to account for damage 
(``flaw tolerant safe-life'' and ``fail-safe''), referred to as flaw 
tolerant methods. The original (``safe-life'') method contained in 
Amendment 29-28 can be used if either of the two new methods requiring 
damage evaluation is 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'' PSEs to determine 
retirement time. The flaw tolerant ``fail-safe'' method is based on a 
crack growth life in a purposely ``flawed'' PSE to determine inspection 
requirements.
    The ``safe-life'' method is based on a crack initiation time in a 
``non-flawed'' PSE to determine 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 the working group addressed was the 
equivalency of the two flaw tolerant methods. While both can be used to 
assess 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, their effectiveness cannot be evaluated 
without considering the details of a specific application. 
Additionally, while using the flaw tolerant safe-life method for 
establishing an inspection interval is not within the intent of the 
Amendment 29-28, the fail-safe method for establishing retirement times 
has been accepted as meeting its intent.

B. Related Actions

    The FAA has a separate rulemaking activity to address FTE of a 
composite structure. Because rotorcraft manufacturers increased the use 
of advanced composite materials for their 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.

C. Summary of the NPRM

    The FAA published the NPRM for this rule in the Federal Register on 
March 12, 2010 (75 FR 11799). The comment period for the NPRM was 
scheduled to close on June 10, 2010. In response to a European Aviation 
Safety Agency (EASA) request, the FAA extended the comment period 
closing date to July 30, 2010 (published in the Federal Register May 5, 
2010, 75 FR 24501). The FAA received 3 comments from Transport Canada.

D. General Overview of Comments

    Although the 3 comments are discussed more fully in the discussion 
section of this final rule, in summary, they deal with the following 
two subjects:
     Acceptability in rotorcraft of some PSE structures crack 
growth methodology allowed in fixed-wing aircraft; and
     Suggested rewording of paragraph (f) for clarification.

III. Discussion of Public Comments and Final Rule

A. Acceptability in Rotorcraft of Some PSE Structures Crack Growth 
Methodology Allowed in Fixed-Wing Aircraft

    Transport Canada asked if some PSEs on rotorcraft, especially 
airframe structures, may be considered to meet the inspection 
requirement without being subjected to a requirement for retirement 
based solely on the crack growth methodology. The commenter believes 
that the crack growth methodology may be used for fixed-wing aircraft 
to determine inspection intervals (and, in the process, inspection 
techniques) without requiring the retirement of the PSEs.
    Because of the vastly different dynamic characteristics of 
rotorcraft when compared to fixed-wing aircraft, we do not concur with 
the commenter's proposal. The rule requires both appropriate 
inspections and a retirement time. If an inspection cannot be 
established within the limits of geometry, inspectability, or good 
design practice, then the applicant must establish supplemental 
procedures in conjunction with the PSE retirement time. This rule does 
not allow inspections only for PSEs. The rule requires inspections and 
retirement times. If inspections cannot be established within certain 
conditions, then supplemental procedures, in conjunction with the PSE 
retirement time, must be established. Therefore, the FAA is adopting 
the rules as proposed in the NPRM.

B. Rewording of Paragraph (f) for Clarification

    Transport Canada suggested that paragraph (f) needs rewording to 
avoid possible misunderstanding or misinterpretation. It comments that:
     The term ``allowable damage'' has been widely used by some 
aircraft

[[Page 75438]]

manufacturers to set a limit for the damages, below which there is no 
need for repair. The commenter suggested this sentence should be 
reworded to clearly indicate that the residual strength of the 
remaining structures is required to successfully carry limit loads.
     If the second sentence of paragraph (f) is intended to 
require a determination of the critical size of damage in order to 
determine inspection intervals, the phrase ``within its operational 
life'' should be removed. However, if it is intended to require limit 
loads to be applied to ensure that, within an inspection interval, the 
remaining structures would carry successfully the limit loads, the 
phrase ``within its operational life'' should be replaced with ``within 
an inspection interval.''
    As used in the proposal, the FAA intends the ``allowable damage'' 
to be the maximum damage at which the rotorcraft structure is capable 
of carrying the limit load. This ``allowable damage'' would be 
determined during the FTE. Once the rotorcraft is in service, any 
damage detected during an inspection interval must be repaired or the 
part must be replaced before further flight.
    The residual strength is based on the maximum damage determined 
from the threat assessment for which the structure retains its limit 
load capability. During the damage growth, the damage may be undetected 
for some time between inspection intervals. Thus, the applicant must 
show that the structure retains its limit load capability for a 
determined maximum damage when evaluating the residual strength in 
order to avoid a catastrophic failure. To clarify this requirement, we 
have reworded paragraph (f).

IV. Regulatory Notices and Analyses

A. Regulatory Evaluation

    Changes to Federal regulations must undergo several economic 
analyses. First, Executive Order 12866 and Executive Order 13563 
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 final 
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 
final 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) Is ``non-significant'' as defined in DOT's Regulatory Policies 
and Procedures;
    (4) Will have a non-significant economic impact on a substantial 
number of small entities;
    (5) Will not have a significant effect on international trade; and
    (6) Will 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 final 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 final rule consist of the value of lives and 
property saved due to avoiding accidents involving part 29 rotorcraft. 
Nine Transport Category rotorcraft accidents could have been avoided by 
this rule over the past 27-year historical period. The potential 
benefit of this final rule will be to avoid at least two of these 
accidents with a value of approximately $12.9 million ($5.6 million in 
present value).
Cost of This Rule
    We estimate the costs of this final 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 will incur costs of $532,000 
($293,000 in present value) and operators of 14 CFR part 29 helicopters 
will incur costs of $8.5 million ($2.6 million in present value).

B. 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 75439]]

determination, and the reasoning should be clear.
    No comments were received on the Regulatory Flexibility 
Determination in the NPRM.
    This final rule will 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 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 
final rule will have a significant economic impact on a substantial 
number of part 29 helicopter manufacturers.
[GRAPHIC] [TIFF OMITTED] TR02DE11.095

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 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.
    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 will meet the SBA definition of 
a small entity. Thus, this final rule will affect a substantial

[[Page 75440]]

number of transport category helicopter operators.
    Based on the information received from industry representatives, 
the cost of this final rule to a part 29 helicopter operator will be 
$1,600 for an inspection that must be performed every three years on 
each part 29 helicopter that is certificated under this final rule. 
This will 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 final rule will add less than one direct 
hour of operating costs per year to a typical part 29 helicopter. 
Although this will be an increase in costs, this will not be a 
substantial increase in costs.
    Consequently, as the FAA Administrator, I certify that this final 
rule will not have a significant economic impact on a substantial 
number of part 29 rotorcraft manufacturers or operators.

C. 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 final rule and 
incorporates international standards in this regulation and therefore 
is in compliance with the Trade Agreements Act.

D. 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 $143.1 million in lieu of 
$100 million. This final rule does not contain such a mandate.

E. Paperwork Reduction Act

    The Paperwork Reduction Act of 1995 requires that the FAA consider 
the impact of paperwork and other information collection burdens 
imposed on the public. According to the 1995 amendments to the 
Paperwork Reduction Act (5 CFR 1320.8(b)(2)(vi)), an agency may not 
collect or sponsor the collection of information, nor may it impose any 
information collection requirement unless it displays a currently valid 
Office of Management and Budget (OMB) control number.
    This final rule will impose 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 
collection requirements associated with this rule to OMB for its 
review. Notice of OMB approval for this information collection will be 
published in a future Federal Register document.
    Summary: This rule revises the FTE safety requirements to address 
advances in structural fatigue substantiation technology for metallic 
structures. An increased level of safety will be provided by avoiding 
or reducing catastrophic fatigue failures of metallic structures. These 
increased safety requirements will help ensure that should accidental 
damage occur during manufacturing or within the 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 amendment would lead to a harmonized 
international standard.
    Public comments: No public comments were received on the 
information collection requirements discussed in the NPRM.
    Use: 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 will 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 
amendment 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 record keeping hours. The corresponding annual inspection 
hours are 197.1 (see table 12-1). The total annual certification 
reporting and record keeping 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
------------------------------------------------------------------------
                                                             Number of
                          Item                                 hours
------------------------------------------------------------------------
             Certification Reporting and Recordkeeping Hours
------------------------------------------------------------------------
Reporting and Recordkeeping Hours per Certification.....           322.5
New Certifications......................................             6.0
Total Certification Reporting and Recordkeeping Hours...         1,935.0
Number of Years.........................................            27.0
Annual Certification Reporting and Recordkeeping Hours              71.7
------------------------------------------------------------------------

[[Page 75441]]

 
              Inspection Reporting and Recordkeeping Hours
------------------------------------------------------------------------
Reporting and Recordkeeping Hours per Inspection........             1.0
Total Aircraft Inspections..............................         5,322.0
Total Inspection Reporting and Recordkeeping Hours......         5,322.0
Number of Years.........................................            27.0
Annual Inspection Reporting and Recordkeeping Hours                197.1
------------------------------------------------------------------------


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

F. International Compatibility

    In keeping with U.S. obligations under the Convention on 
International Civil Aviation, it is FAA policy to conform to 
International Civil Aviation Organization (ICAO) Standards and 
Recommended Practices to the maximum extent practicable. The FAA has 
reviewed the corresponding ICAO Standards and Recommended Practices and 
has identified no differences with these regulations.

G. 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 rulemaking action qualifies for the categorical 
exclusion identified in paragraph 312F and involves no extraordinary 
circumstances.

H. Regulations Affecting Intrastate Aviation in Alaska

    Section 1205 of the FAA Reauthorization Act of 1996 (110 Stat. 
3213) requires the FAA, when modifying its regulations 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. In the NPRM, the 
FAA requested comments on whether the proposed rule should apply 
differently to intrastate operations in Alaska. The agency did not 
receive any comments, and has determined, based on the administrative 
record of this rulemaking, that there is no need to make any regulatory 
distinctions applicable to intrastate aviation in Alaska.

V. Executive Order Determinations

A. Executive Order 13132, Federalism

    The FAA has analyzed this final rule under the principles and 
criteria of Executive Order 13132, Federalism. The agency determined 
that this action will not have a substantial direct effect on the 
States, or the relationship between the Federal Government and the 
States, or on the distribution of power and responsibilities among the 
various levels of government, and, therefore, does not have Federalism 
implications.

B. Executive Order 13211, Regulations That Significantly Affect Energy 
Supply, Distribution, or Use

    The FAA analyzed this final rule under Executive Order 13211, 
Actions Concerning Regulations that Significantly Affect Energy Supply, 
Distribution, or Use (May 18, 2001). The agency has determined that it 
is not a ``significant energy action'' under the executive order and it 
is not likely to have a significant adverse effect on the supply, 
distribution, or use of energy.

VI. How To Obtain Additional Information

A. Rulemaking Documents

    An electronic copy of this rulemaking document may be obtained by 
using the Internet.
    1. Search the Federal Docket Management System at https://www.regulations.gov;

[[Page 75442]]

    2. Visit the FAA's Regulations and Policies Web page at https://www.faa.gov/regulations_policies/or
    3. Access the Government Printing Office's Web page at https://www.gpoaccess.gov/fr/.
    Copies may also be obtained by sending a request (identified by 
notice, amendment, or docket number of this rulemaking) to the Federal 
Aviation Administration, Office of Rulemaking, ARM-1, 800 Independence 
Avenue SW., Washington, DC 20591, or by calling (202) 267-9680.

B. Comments Submitted to the Docket

    Comments received may be viewed by going to https://www.regulations.gov and following the online instructions to search the 
docket number for this action. Anyone is able to search the electronic 
form of all comments received into any of the FAA's dockets by the name 
of the individual submitting the comment (or signing the comment, if 
submitted on behalf of an association, business, labor union, etc.).

C. Small Business Regulatory Enforcement Fairness Act

    The Small Business Regulatory Enforcement Fairness Act (SBREFA) of 
1996 requires FAA to comply with small entity requests for information 
or advice about compliance with statutes and regulations within its 
jurisdiction. A small entity with questions regarding this document, 
may contact its local FAA official, or the person listed under the FOR 
FURTHER INFORMATION CONTACT heading at the beginning of the preamble. 
To find out more about SBREFA on the Internet, visit https://www.faa.gov/regulations_policies/rulemaking/sbre_act/.

List of Subjects in 14 CFR Part 29

    Aircraft, Aviation safety.

The Amendment

    In consideration of the foregoing, the Federal Aviation 
Administration amends chapter I of Title 14, Code of Federal 
Regulations as follows:

PART 29--AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT

0
1. The authority citation for part 29 continues to read as follows:

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


0
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 under 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--
    (1) Catastrophic failure means an event that could prevent 
continued safe flight and landing.
    (2) 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 to 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 by 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 that 
substantiates the maximum damage size assumed in the fatigue tolerance 
evaluation. 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.
    (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 November 22, 2011.
J. Randolph Babbitt,
Administrator.
[FR Doc. 2011-30941 Filed 12-1-11; 8:45 am]
BILLING CODE 4910-13-P