Document ID: FAA-2007-28502-0008
Agency: faa
Document Type: Rule
Title: Airworthiness Standards; Aircraft Engine Standards Overtorque Limits
Posted Date: 2009-09-02T04:00Z

[Federal Register: September 2, 2009 (Volume 74, Number 169)]
[Rules and Regulations]               
[Page 45307-45311]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr02se09-2]                         

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Parts 1 and 33

[Docket No. 2007-28502; Amendment No. 1-65, 33-30]
RIN 2120-AJ06

 
Airworthiness Standards; Aircraft Engine Standards Overtorque 
Limits

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: This rule will amend the certification standards for aircraft 
engines to establish requirements for approval of maximum engine 
overtorque. Specifically, this action will add a new engine overtorque 
test, amend engine ratings and operating limits, and define maximum 
engine overtorque for certain turbopropeller and turboshaft engines. 
The rule will

[[Page 45308]]

harmonize applicable United States (U.S.) and European standards and 
simplify airworthiness approvals for import and export of aircraft 
engines.

DATES: This amendment becomes effective November 2, 2009.

FOR FURTHER INFORMATION CONTACT: For technical questions concerning 
this final rule contact Tim Mouzakis, Engine and Propeller Directorate, 
Standards Staff, ANE-110, Federal Aviation Administration (FAA), New 
England Region, 12 New England Executive Park, Burlington, 
Massachusetts 01803; telephone (781) 238-7114; facsimile (781) 238-
7199; electronic mail ``Timoleon.Mouzakis@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 promulgated under the authority described in 
subtitle VII, part A, subpart III, section 44701, ``General 
requirements.'' Under that section, the FAA is charged with promoting 
safe flight of civil aircraft in air commerce by prescribing 
regulations for practices, methods, and procedures the Administrator 
finds necessary for safety in air commerce, including minimum safety 
standards for aircraft engines. This regulation is within the scope of 
that authority because it updates the existing regulations for aircraft 
engine standards overtorque limits.

Background

    Part 33 of Title 14, Code of Federal Regulations (14 CFR part 33) 
prescribes airworthiness standards for original and amended type 
certificates for aircraft engines. The European Aviation Safety Agency 
(EASA) Certification Specification--Engines (CS-E) prescribes 
corresponding airworthiness standards to certify aircraft engines in 
Europe. While part 33 and the CS-E are similar, they differ in several 
respects. These differences result in added costs, delays, and time 
required for certification. In addition, U.S. aircraft engine 
manufacturers face additional costs when seeking certification of their 
engine designs by the EASA for export. CS-E contains specific standards 
for approval of maximum overtorque limits.
    Currently, part 33 does not contain explicit standards for a 
maximum engine overtorque limit. Engine manufacturers apply for and 
obtain FAA approvals of maximum overtorque limits based on the results 
of certification engine tests and analysis that do not directly address 
considerations for maximum overtorque limits.
    The FAA tasked the Aviation Rulemaking Advisory Committee (ARAC), 
through its Engine Harmonization Working Group (EHWG), to provide 
advice and recommendations on proposed standards for engine overtorque. 
We published that tasking in the Federal Register on October 20, 1998 
(63 FR 56059). This final rule is based on ARAC's recommendations.

Summary of the NPRM

    The FAA published a notice of proposed rulemaking (NPRM) on March 
26, 2008 (73 FR 15955). The proposal adds a new definition to Sec.  
1.1, changes to Sec.  33.7, and introduces Sec.  33.84. These proposed 
changes would add a new engine overtorque test, amend engine ratings 
and operating limitations, and define maximum engine overtorque for 
certain turbopropeller and turboshaft engines. The proposal would 
harmonize U.S. and European standards for approving engine overtorque 
transients for turbopropeller and turboshaft engines with free power 
turbines. The comment period closed June 24, 2008.

Summary of Comments

    The FAA received four comment letters, one from a British engine 
manufacturer (Rolls-Royce Corporation), one from a foreign regulatory 
authority (Transport Canada), and two from law students at the 
University of Central Missouri. All four comment letters support the 
general intent of the proposed rule. However, Transport Canada raised 
specific concerns that were addressed by clarifying revisions to 
proposed Sec. Sec.  33.7 and 33.84. A detailed discussion of changes to 
the final rule is presented below.

Discussion of the Final Rule

    The final rule establishes a standard for applicants to use when 
applying for and obtaining approval of a maximum engine overtorque 
limit. This rule harmonizes FAA and EASA standards and simplifies 
airworthiness approvals for the import and export of turbopropeller and 
turboshaft engines with free power turbines. The rule also improves 
safety by stating clear requirements for maximum engine overtorque 
limits.
    Below are specific comments from Transport Canada and our responses 
to them.
    1. The approach proposed, to seek an ``approval'' for overtorque, 
is inconsistent with the approach used for ``overspeed'' and 
``overtemperature''. Transport Canada suggested the approach for 
``overtorque'' be similar to ``overspeed'' and ``overtemperature''.
    We do not agree. Overspeed and overtemperature are transients which 
are approved when they occur during normal engine operation, e.g., a 
short duration transient exceedance of a rating (speed, temperature, or 
torque) as the engine stabilizes at a new operating condition following 
an acceleration. As proposed in the NPRM, the ``maximum engine 
overtorque'' is optional to the applicant. This optional operating 
condition is not an approved transient, but an ``over limit'' condition 
which may occur due to a failure. The applicant can choose whether to 
declare any maximum engine overtorque. However, to ensure the 
regulation is clear, we have revised proposed Sec.  33.7 to clarify 
that engine ratings and operating limitations include both the existing 
transient engine overtorque and the new maximum engine overtorque 
``over limit''. We also revised Sec.  33.87(a)(8) to clarify the 
requirement applies to all transient functions, including engine 
overtorque. This makes clear that transient engine overtorque is 
addressed in Sec.  33.87(a)(8) and maximum engine overtorque in Sec.  
33.84.
    2. The definition of ``Maximum engine overtorque'' in Sec.  1.1 is 
not necessary since part 33 does not have similar definitions for 
``overspeed'' or ``overtemperature''.
    The FAA does not agree. Overspeed and overtemperature in part 33 
are transient events and part of the normal operation of the engine as 
defined in the type design. Maximum engine overtorque is an ``over 
limit'' condition that could last up to 20 seconds and is a result of 
some failure. A definition in Sec.  1.1 is necessary as maximum engine 
overtorque is unique in its application to turbopropeller and 
turboshaft engines. Explanation is required to define the context in 
which this condition would apply and specific exclusions related to it. 
Transient overspeed and overtemperature are general and well understood 
terms used widely throughout part 33. No maintenance action is 
necessary by the aircraft operator provided the cause of the failure is 
corrected, and the engine meets the new maximum engine overtorque limit 
requirement.
    3. The proposed Sec.  33.84 overtorque test requirement should be 
independent from the Sec.  33.87 endurance test requirement. Transport 
Canada also proposed the overtorque test requirement be at least 10% 
torque over

[[Page 45309]]

the highest torque limit for any rating longer than 2 minutes.
    We agree, in part, that the overtorque and endurance tests may be 
performed separately. However, we did not set an overtorque limit 
because it is the applicant's responsibility to decide the maximum 
engine overtorque for the engine.
    Lastly, we made a clarifying change to wording in the first 
sentence of Sec.  33.84(b)(4). This change did not alter our intent or 
the meaning of the proposed regulation.

Paperwork Reduction Act

    The Paperwork Reduction Act of 1995 (44 U.S.C. 3507(d)) requires 
the FAA to consider the impact of paperwork and other information 
collection burdens imposed on the public. We have determined that there 
are no new information collection requirements associated with this 
amendment.

International Compatibility

    In keeping with U.S. obligations under the Convention on 
International Civil Aviation, it is FAA policy to comply with 
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 
determined there are no differences with these regulations.

Regulatory Evaluation Summary

Regulatory Evaluation, Regulatory Flexibility Determination, 
International Trade 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 final rule.
    Department of Transportation Order DOT 2100.5 prescribes policies 
and procedures for simplification, analysis, and review of regulations. 
If the expected cost impact is so minimal that a proposed or final rule 
does not warrant a full evaluation, this order permits that a statement 
to that effect and the basis for it be included in the preamble if a 
full regulatory evaluation of the cost and benefits is not prepared. 
Such a determination has been made for this final rule. The reasoning 
for this determination follows:
    This final rule coordinates FAA engine requirements with existing 
EASA engine requirements that manufacturers must currently meet in 
order for their engines to be used in European operations. 
Consequently, this rule will allow engine manufacturers to meet one 
requirement rather than separate requirements for FAA/EASA 
certification. There were no public comments on the economic impact of 
the NPRM. As a result, the expected outcome will be a minimal impact 
with positive net benefits.
    A regulatory evaluation was not prepared. This final rule 
incorporates existing certification practices, while maintaining the 
existing level of safety. The benefits of this rule justify the costs 
and the existing level of safety will be preserved. The Office of 
Management and Budget has determined that this final rule is a 
``significant regulatory action'' because it harmonizes U.S. aviation 
standards with those of other civil aviation authorities.

Regulatory Flexibility Determination

    The Regulatory Flexibility Act of 1980 (Pub. L. 96-354) (RFA) 
establishes ``as a principle of regulatory issuance that agencies shall 
endeavor, consistent with the objectives of the rule and of applicable 
statutes, to fit regulatory and informational requirements to the scale 
of the businesses, organizations, and governmental jurisdictions 
subject to regulation. To achieve this principle, agencies are required 
to solicit and consider flexible regulatory proposals and to explain 
the rationale for their actions to assure that such proposals are given 
serious consideration.'' 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 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 RFA. 
However, if an agency determines that a rule is not expected to have a 
significant economic impact on a substantial number of small entities, 
section 605(b) of the RFA provides that the head of the agency may so 
certify and a regulatory flexibility analysis is not required. The 
certification must include a statement providing the factual basis for 
this determination, and the reasoning should be clear.
    We stated in the initial Regulatory Flexibility Analysis that we 
believed the rule would be a cost-relieving rule as it harmonizes with 
the EASA aviation regulations. We received no comments to the contrary.
    Therefore, as the FAA Administrator, I certify that this rule will 
not have a significant economic impact on a substantial number of small 
entities.

International Trade Analysis

    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 any 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 standards have a 
legitimate domestic objective, such as the protection of safety, and do 
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. This rule 
uses international standards as the basis for regulation and thus is 
consistent with the Trade Agreements Act.

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 
(in 1995 dollars) in any one year by State, local, and tribal 
governments, in the aggregate, or by the private sector; such a mandate 
is deemed to be a ``significant

[[Page 45310]]

regulatory action.'' The FAA currently uses an inflation-adjusted value 
of $136.1 million in lieu of $100 million. This final rule does not 
contain such a mandate, therefore, the requirements of Title II of the 
Act do not apply.

Executive Order 13132, Federalism

    The FAA has analyzed this proposed rule under the principles and 
criteria of Executive Order 13132, Federalism. We determined that this 
action will not have a substantial direct effect on the States, on 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.

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 Chapter 3, paragraph 312d, and involves no 
extraordinary circumstances.

Regulations That Significantly Affect Energy Supply, Distribution, or 
Use

    The FAA has analyzed this final rule 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, and is not 
likely to have a significant adverse effect on the supply, 
distribution, or use of energy.

Availability of Rulemaking Documents

    You can get an electronic copy of rulemaking documents using the 
Internet by--
    1. Searching the Federal eRulemaking Portal (http://
www.regulations.gov);
    2. Visiting the FAA's Regulations and Policies Web page at http://
www.faa.gov/regulations_policies/; or
    3. Accessing the Government Printing Office's Web page at http://
www.gpoaccess.gov/fr/index.html.
    You can also get a copy by sending a request to the Federal 
Aviation Administration, Office of Rulemaking, ARM-1, 800 Independence 
Avenue, SW., Washington, DC 20591, or by calling (202) 267-9680. Make 
sure to identify the amendment number or docket number of this 
rulemaking.
    Anyone is able to search the electronic form of all comments 
received into any of our 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.). You may review DOT's 
complete Privacy Act statement in the Federal Register published on 
April 11, 2000 (Volume 65, Number 70; Pages 19477-78) or you may visit 
http://DocketsInfo.dot.gov.

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. If you are a small entity and you have a question 
regarding this document, you may contact your local FAA official, or 
the person listed under the FOR FURTHER INFORMATION CONTACT heading at 
the beginning of the preamble. You can find out more about SBREFA on 
the Internet at http://www.faa.gov/regulationspolicies/rulemaking/
sbre_act/.

List of Subjects

14 CFR Part 1

    Air transportation, Aircraft, Aviation safety, Safety.

14 CFR Part 33

    Air transportation, Aircraft, Aviation safety, Safety.

The Amendment

0
In consideration of the foregoing, the Federal Aviation Administration 
amends parts 1 and 33 of Title 14, Code of Federal Regulations (14 CFR 
parts 1 and 33) as follows:

PART 1--DEFINITIONS AND ABBREVIATIONS

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

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

0
2. Amend Sec.  1.1 by adding the definition of ``Maximum engine 
overtorque'' in alphabetical order, to read as follows:

Sec.  1.1  General definitions.

* * * * *
    Maximum engine overtorque, as it applies to turbopropeller and 
turboshaft engines incorporating free power turbines for all ratings 
except one engine inoperative (OEI) ratings of two minutes or less, 
means the maximum torque of the free power turbine rotor assembly, the 
inadvertent occurrence of which, for periods of up to 20 seconds, will 
not require rejection of the engine from service, or any maintenance 
action other than to correct the cause.
* * * * *

PART 33--AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES

0
3. The authority citation for part 33 continues to read as follows:

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

0
4. Amend Sec.  33.7 by redesignating paragraph (c)(16) as (c)(18) and 
adding new paragraphs (c)(16) and (c)(17) to read as follows:

Sec.  33.7  Engine ratings and operating limitations.

* * * * *
    (c) * * *
    (16) Transient engine overtorque, and number of overtorque 
occurrences.
    (17) Maximum engine overtorque for turbopropeller and turboshaft 
engines incorporating free power turbines.
* * * * *

0
5. Section 33.84 is added to read as follows:

Sec.  33.84.  Engine overtorque test.

    (a) If approval of a maximum engine overtorque is sought for an 
engine incorporating a free power turbine, compliance with this section 
must be demonstrated by testing.
    (1) The test may be run as part of the endurance test requirement 
of Sec.  33.87. Alternatively, tests may be performed on a complete 
engine or equivalent testing on individual groups of components.
    (2) Upon conclusion of tests conducted to show compliance with this 
section, each engine part or individual groups of components must meet 
the requirements of Sec.  33.93(a)(1) and (a)(2).
    (b) The test conditions must be as follows:
    (1) A total of 15 minutes run at the maximum engine overtorque to 
be approved. This may be done in separate runs, each being of at least 
2\1/2\ minutes duration.
    (2) A power turbine rotational speed equal to the highest speed at 
which the maximum overtorque can occur in service. The test speed may 
not be more than the limit speed of take-off or OEI ratings longer than 
2 minutes.
    (3) For engines incorporating a reduction gearbox, a gearbox oil 
temperature equal to the maximum temperature when the maximum engine 
overtorque could occur in service; and for all other engines, an oil 
temperature within the normal operating range.

[[Page 45311]]

    (4) A turbine entry gas temperature equal to the maximum steady 
state temperature approved for use during periods longer than 20 
seconds when operating at conditions not associated with 30-second or 2 
minutes OEI ratings. The requirement to run the test at the maximum 
approved steady state temperature may be waived by the FAA if the 
applicant can demonstrate that other testing provides substantiation of 
the temperature effects when considered in combination with the other 
parameters identified in paragraphs (b)(1), (b)(2) and (b)(3) of this 
section.

0
6. Amend Sec.  33.87 by revising paragraph (a)(8) to read as follows:

Sec.  33.87  Endurance test.

    (a) * * *
    (8) If the number of occurrences of either transient rotor shaft 
overspeed, transient gas overtemperature or transient engine overtorque 
is limited, that number of the accelerations required by paragraphs (b) 
through (g) of this section must be made at the limiting overspeed, 
overtemperature or overtorque. If the number of occurrences is not 
limited, half the required accelerations must be made at the limiting 
overspeed, overtemperature or overtorque.
* * * * *

    Issued in Washington, DC, on August 21, 2009.
J. Randolph Babbitt,
Administrator.
[FR Doc. E9-20960 Filed 9-1-09; 8:45 am]

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