Airworthiness Standards: Rotorcraft Turbine Engines One-Engine-Inoperative (OEI) Ratings, Type Certification Standards, 25207-25214 [E7-7943]

Agencies

• Federal Aviation Administration
• DEPARTMENT OF TRANSPORTATION

[Federal Register Volume 72, Number 86 (Friday, May 4, 2007)]
[Proposed Rules]
[Pages 25207-25214]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E7-7943]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Parts 1 and 33

[Docket No. FAA-2007-27899; Notice No. 07-05]
RIN 2120-AI96


Airworthiness Standards: Rotorcraft Turbine Engines One-Engine-
Inoperative (OEI) Ratings, Type Certification Standards

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The Federal Aviation Administration (FAA) is proposing to 
amend OEI rating definitions and type certification standards for 30-
second OEI, 2-minute OEI, and 30-minute OEI ratings for rotorcraft 
turbine engines. This proposed rule, if adopted, would revise the 
ratings' standards to reflect recent analyses of the ratings' usage and 
lessons learned from completed engine

[[Page 25208]]

certifications and service experience. This proposal harmonizes FAA 
type certification standards for these ratings with the requirements of 
the European Aviation Safety Agency in the Certification Specifications 
for Engines (CS-E) and with proposed requirements for Transport Canada 
Civil Aviation. If adopted, the proposed changes would establish nearly 
uniform certification standards for ratings for rotorcraft turbine 
engines certificated in the United States under part 33 and in European 
countries under CS-E, thus simplifying airworthiness approvals for 
import and export.

DATES: Send your comments on or before August 2, 2007.

ADDRESSES: You may send comments, identified by Docket No. FAA-2007-
27899, using any of the following methods:
     DOT Docket Web site: Go to https://dms.dot.gov and follow 
the instructions for sending your comments electronically.
     Government-wide rulemaking Web site: Go to https://www.regulations.gov and follow the instructions for sending your 
comments electronically.
     Mail: Docket Management Facility; U.S. Department of 
Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, 
Washington, DC 20590-0001.
     Fax: 1-202-493-2251.
     Hand Delivery: Room PL-401 on the plaza level of the 
Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    For more information on the rulemaking process, see the 
SUPPLEMENTARY INFORMATION section of this document.
    Privacy: We will post all comments we receive, without change, to 
https://dms.dot.gov, including any personal information that you 
provide. For more information, see the Privacy Act discussion in the 
SUPPLEMENTARY INFORMATION section of this document.
    Docket: To read background documents or comments received, go to 
https://dms.dot.gov at any time or to Room PL-401 on the plaza level of 
the Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.

FOR FURTHER INFORMATION CONTACT: Dorina Mihail, Engine and Propeller 
Standards Staff, ANE-110, Engine and Propeller Directorate, Aircraft 
Certification Service, FAA, New England Region, 12 New England 
Executive Park, Burlington, Massachusetts 01803-5229; (781) 238-7153; 
facsimile: (781) 238-7199; e-mail: dorina.mihail@faa.gov.

SUPPLEMENTARY 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. We ask that you send us two copies of written 
comments.
    We will file in the docket all comments we receive, as well as a 
report summarizing each substantive public contact with FAA personnel 
concerning this proposed rulemaking. The docket is available for public 
inspection before and after the comment closing date. If you wish to 
review the docket in person, go to the address in the ADDRESSES section 
of this preamble between 9 a.m. and 5 p.m., Monday through Friday, 
except Federal holidays. You may also review the docket using the 
Internet at the Web address in the ADDRESSES section.
    Privacy Act: Using the search function of our docket Web site, 
anyone can find and read the comments received into any of our dockets, 
including the name of the individual sending the comment (or signing 
the comment 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 (65 FR 19477-78) or you may visit 
https://dms.dot.gov.
    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 late if it is possible to do so without incurring 
expense or delay. We may change this proposal in light of the comments 
we receive.
    If you want the FAA to acknowledge receipt of your comments on this 
proposal, include with your comments a pre-addressed, stamped postcard 
on which the docket number appears. We will stamp the date on the 
postcard and mail it to you.

Availability of Rulemaking Documents

    You can get an electronic copy using the Internet by:
    1. Searching the Department of Transportation's electronic Docket 
Management System (DMS) Web page (https://dms.dot.gov/search):
    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.access.gpo.gov/su_docs/aces/aces140.html.
    You can also get a copy by sending a request to the Federal 
Aviation Administration, Office of Rulemaking, ARM-1, 800 Independence 
Avenue, SW., Washington, DC 20591, or by calling (202) 267-9680. Make 
sure to identify the docket number, notice number, or amendment number 
of this rulemaking.

Background

    The One-Engine-Inoperative (OEI) rating powers provide rotorcraft 
with higher than takeoff and maximum continuous rating powers during 
takeoff, cruise, and landing when one or more engines of a multi-engine 
rotorcraft fails or is shutdown. These OEI rating powers enable the 
rotorcraft to continue safe flight until it reaches a suitable landing 
site. Part 33 prescribes airworthiness standards for 30-second OEI, 2-
minute OEI, 2\1/2\-minute OEI, 30-minute OEI, and other OEI ratings for 
the issuance of type certificates for rotorcraft turbine engines. All 
OEI ratings are optional ratings that engine manufacturers may select 
from those specified in Sec.  33.7.
    The Certifications Specifications--Engines prescribe corresponding 
airworthiness standards of the European Aviation Safety Agency for 
these ratings. While these standards are similar, they differ in 
certain regulations. Non-uniform standards impose a regulatory hardship 
on applicants seeking certification under both sets of standards in the 
form of additional costs and delays in the time required for 
certification.
    The FAA is committed to promoting harmonization. As part of this 
commitment, the FAA, with the European Joint Aviation Authorities (JAA) 
and Transport Canada Civil Aviation, developed a harmonized Terms of 
Reference for ``2-Minute and 30-Second One-Engine-Out Ratings'' in 
April 1992. The Terms of Reference established a joint effort to review 
and harmonize the requirements and interpretations for OEI ratings 
under part 33 and the corresponding Joint Aviation Requirements--
Engines (JAR-E). The Aviation Rulemaking Advisory Committee (ARAC) 
assigned the task of harmonizing the differing OEI ratings to its 
Engine Harmonization Working Group, which consisted of representatives 
from the FAA, JAA, TC,

[[Page 25209]]

as well as from U.S., Canadian, and European industries.
    On February 29, 2000, the Engine Harmonization Working Group 
reported its recommendations to the ARAC, which recommended that the 
FAA proceed with rulemaking. This NPRM reflects the ARAC 
recommendations.

Section-by-Section Discussion of the Proposals

    The working group developed and agreed to the following proposals. 
The proposed changes to parts 1 and 33 contain language similar to that 
proposed for JAR-E, and subsequently adopted in the CS-E, thereby 
establishing equivalency and creating consistency between the 
regulations.

Section 1.1 Definitions

    The current definitions of rated OEI powers refer to engine failure 
but not to engine shutdown. We are proposing, therefore, to revise the 
definition of rated 30-second OEI, rated 2-minute OEI, rated 2\1/2\-
minute OEI, rated 30-minute OEI, and rated continuous OEI powers to 
include engine shutdown. In addition, to be consistent with the usage 
definitions of 30-second OEI and 2-minute OEI ratings, we are proposing 
to revise the ``period of use'' for the 2\1/2\-minute OEI rating from 
``a period of use'' to ``periods of use.''

Section 33.5 Instruction Manual for Installing and Operating the Engine

    We are proposing to add a new Sec.  33.5(b)(4), applicable to 
rotorcraft engines having one or more OEI ratings, which would require 
applicants to provide engine data to aircraft manufacturers in support 
of aircraft power availability requirements, such as those specified in 
Sec. Sec.  27.45(f) and 29.45(f). Since the power assurance data will 
not include a check of the highest OEI rating power level due to 
potential rapid engine hardware deterioration, the applicant must 
provide the necessary engine performance characteristics and 
variability to the engine installer. This data will enable the 
installer to establish power assurance procedures that enable the 
extrapolation of data to the highest OEI rating power. The engine 
database should include: a thermodynamic model; data gained from 
experience during development and certification testing; and data 
derived from service experience from engines of similar design, 
whenever applicable.

Section 33.29 Instrument Connection

    We are proposing to revise Sec.  33.29(c) to specify that the 
applicant must provide a means or a provision for a means to record the 
entry into the defined 30-second OEI and 2-minute OEI rating power 
bands. The applicant, for example, an engine manufacturer, may satisfy 
``a means'' by providing a recorder to record entry into the OEI power 
bands. Alternatively, the applicant may fulfill ``a provision for a 
means'' by specifying that the installer provide a recorder to record 
entry into the OEI power bands.
    The revised proposal would also require a means to indicate to the 
pilot the entry into the power bands, the corresponding impending time 
expiration, and the time expiration point. The automatic recording 
system must record the number of usages of 30-second OEI and/or 2-
minute OEI rating powers and the time of each usage, or accumulated 
time, including any exceedance of 30-second OEI and 2-minute OEI 
operating limitations or relevant time limitations.
    The automatic recording system should also provide a means to alert 
the maintenance personnel that the usage and/or exceedance of the 30-
second and 2-minute OEI ratings has taken place. The required means for 
alerting the pilot, maintenance personnel, and the automatic recording 
system must not be capable of being reset in flight and must only be 
reset by maintenance personnel after retrieval of recorded data.
    The proposal would delete the redundant design requirements of 
Sec.  33.29(c)(2). The automatic data recording requirements of the 
existing Sec.  33.29(c)(3), with a minor wording change for 
clarification, will become the new Sec.  33.29(c)(2).
    This proposal would add a new requirement designated as new Sec.  
33.29(c)(3) to alert maintenance personnel when the engines have been 
operated at the rating powers and of the need to retrieve the recorded 
engine data. A new Sec.  33.29(c)(4) would specify the requirements for 
verification of the proper operation of indicating, recording, and 
retrieval systems. In addition, a new Sec.  33.29(d) would specify 
resetting the recording on the ground only.

Section 33.67 Fuel System

    The operating conditions requiring the use of 30-second OEI ratings 
may require the pilot to perform simultaneous actions to maintain safe 
flight. Therefore, an automatic means that does not require pilot input 
or control, other than a termination command, must apply and control 
the rating power. This automatic control requirement is intended to 
avoid the need for the pilot to monitor engine parameters, such as 
output shaft torque or power, output shaft speed, gas producer speed, 
and gas path temperature, during the OEI operation. Once the system is 
activated, it automatically controls the 30-second OEI power and 
prevents the engine from exceeding its specified operating limits.
    We are proposing to revise Sec.  33.67(d) to clarify that the 
intent of the proposed ``automatic control'' is to control the engine 
operating conditions, which should not exceed the engine's operating 
limits. The applicant's design, however, should not limit the time at 
which OEI power is used. This will enable the pilot to exceed OEI time 
limitations to safely land the rotorcraft in an in-flight emergency as 
permitted by Sec.  91.3(b).

Section 33.87 Endurance Test

    For rotorcraft engines having 30-second and 2-minute OEI ratings, 
the applicant must consider all applicable paragraphs of Sec.  33.87(a) 
in running the tests under Sec.  33.87(f). However, to reduce test 
complexity, and to improve the flexibility needed to attain the key 
parameters (speed, temperature and torque) during the tests, we are 
proposing to allow that the maximum air bleed for engine and aircraft 
services under Sec.  33.87(a)(5) need not be used for the tests under 
Sec.  33.87(f)(1) through (f)(8) if the applicant can show by testing, 
or analysis based on testing, that the validity of the endurance test 
is preserved. The analysis should include, but is not limited to (1) 
The effect of the bleed air extraction on the engine secondary air 
system that provides cooling air to various engine components, and (2) 
the thermodynamic cycle effects of bleed (e.g., core speed to output 
shaft speed changes) which may enhance the engine's ability to meet the 
teardown inspection requirements of Sec.  33.93(b)(2).
    This proposal would allow the applicant to run the tests under 
Sec. Sec.  33.87(f)(1) through (f)(8) without loading the accessory 
drives and mounting attachments if the applicant can substantiate that 
the durability of any accessory drive or engine component is not 
significantly affected. However, to meet the requirements of Sec.  
33.87(a)(6) without the power turbine accessory drives loaded during 
the test, the applicant must add equivalent power required for loading 
these accessory drives. This power must be added to the output drive 
shaft so that the power turbine rotor assembly is operated at or above 
the levels as when the power turbine accessory drives are loaded.
    This proposal would clarify the intent of the test schedule for the 
first test sequence of the existing Sec.  33.87(f)(4) test

[[Page 25210]]

by adding a new sentence, ``However, where the greatest is the 30-
minute OEI power, that sixty-five minute period shall consist of 30 
minutes at 30-minute OEI power followed by 35 minutes at whichever is 
the greater of continuous OEI power or maximum continuous power.'' The 
proposal would also clarify the idle condition of Sec.  33.87(f)(8) as 
flight idle.
    This proposal would specify that the four test sequences of the 2-
hour test under Sec.  33.87(f) are to be run continuously without 
stoppage. If a stop occurs, the applicant typically would need to 
repeat the interrupted sequence in full. However, the sequence may be 
re-started from the interrupt point if there are technical 
justifications acceptable to the FAA. If the FAA determines that the 
sequence need not be repeated in its entirety, then the test should be 
re-started from a point where the engine thermal condition would be the 
same as at the time of interruption. If an excessive number of 
interruptions occur, the applicant would be required to repeat the 
entire Sec.  33.87(f) test.
    Additionally, we are proposing to revise the test schedule under 
Sec.  33.87(c) for the 30-minute OEI rating to agree with the schedule 
in CS-E. The result would be the harmonization of the endurance test 
schedule for engines having a 30-minute OEI rating. The proposal would 
replace the existing Sec.  33.87(c)(2) with a thirty-minute test at (a) 
Rated maximum continuous power during fifteen of the twenty-five 6-hour 
endurance test cycles; and (b) rated takeoff power during ten of the 
twenty-five 6-hour endurance test cycles. The existing Sec.  
33.87(c)(2) would be redesignated Sec.  33.87(c)(4). The duration of 
the test in the existing Sec.  33.87(c)(3) would be reduced from 2 
hours to 1 hour. The existing Sec.  33.87(c)(4) would be redesignated 
as Sec.  33.87(c)(5) with the number of time and speed increments 
increased from 12 to 15, and with total running time increased from 2 
hours to 2 hours and 30 minutes. The existing Sec.  33.87(c)(5) and 
(c)(6) would be redesignated as Sec.  33.87(c)(6) and (c)(7), 
respectively.

Section 33.88 Engine Overtemperature Test

    We are proposing to delete the existing Sec.  33.88(b), which 
refers to obtaining OEI ratings when the engine does not incorporate a 
means to limit gas temperature. This paragraph is not needed because 
the new Sec.  33.67(d) requires automatic control of the 30-second OEI 
power within its gas temperature limit. The proposal would incorporate 
the existing test requirements in Sec.  33.88(c) into the new Sec.  
33.88(b), which applies only to engines having the combined 30-second 
OEI and 2-minute OEI ratings. We are proposing to revise Sec.  33.88(a) 
to apply to all other ratings, including all OEI ratings other than the 
combination specified above, regardless of whether the engine is 
equipped with an automatic temperature control.

Section 33.93 Teardown Inspection

    In meeting the teardown inspection requirements after the 2-hour 
endurance tests of Sec.  33.87(f), the applicant would be required to 
show that no failure of any significant engine component becomes 
evident during the test, shutdown, or the subsequent teardown 
inspection. For components that are distressed beyond serviceable 
limits by this test, the applicant must show that the inspections and 
mandatory maintenance actions for these components, specified in the 
Instructions for Continued Airworthiness (ICA), are adequate for 
maintaining their continued airworthiness.
    Additionally, the applicant would need to evaluate component 
condition against a minimum hardware condition that can be expected for 
in-service engines. For the purpose of Sec.  33.93(b)(2), engine parts 
that can affect structural integrity include, but are not limited to, 
mounts, cases, bearing supports, shafts, and rotors. We are proposing 
to remove the reference in Sec.  33.93(b)(2) to the above mentioned 
components to emphasize that after the test the applicant needs to 
consider deterioration of any engine component that could affect the 
structural integrity of the engine, not just those listed above.

Appendix A33.4 Airworthiness Limitation Section

    We are proposing to revise A33.4, Airworthiness Limitations Section 
(ALS), by adding a new paragraph for rotorcraft engines having 30-
second OEI and 2-minute OEI ratings. For these engines, we will require 
the applicant to prescribe mandatory post-flight inspection and 
maintenance actions in the ALS of the ICA following the use of these 
ratings. We will also require the applicant to create a mandatory in-
service engine evaluation program to ensure the continued adequacy of 
the airworthiness instructions for the engines.
    The concept of the 30-second OEI and 2-minute OEI ratings is that 
of limited use in service followed by mandatory inspection and 
maintenance. This concept assumes that some engine parts or components 
may not be suitable for further use and will need to be replaced after 
the application of these ratings. The mandatory inspections and 
maintenance actions following the use of 30-second OEI, or 2-minute OEI 
ratings, must be capable of (1) Identifying and correcting any 
component distress that could significantly reduce subsequent engine 
reliability or prevent the engine from achieving 30-second OEI and 2-
minute OEI rating powers; and (2) maintaining the engine in condition 
for safe OEI flight. This proposal requires the applicant to prescribe 
the mandatory post-flight inspection and maintenance actions in the ALS 
of the ICA following the use of either of these two ratings, prior to 
next flight, regardless of the frequency of usage and the condition of 
the engine. The applicant must validate the adequacy of the required 
inspections and maintenance actions.
    The required inspections and maintenance actions are normally 
determined through certification testing supplemented by development 
testing and service experience of engines of the same type with similar 
design at the time of certification. Differences, however, may exist in 
hardware conditions and power availability characteristics between in-
service engines and the conditions and characteristics of the engine 
prior to the Sec.  33.87(f) tests. Similarly, differences may exist in 
power assurance characteristics for in-service engines after usage of 
30-second or 2-minute OEI ratings and the characteristics observed 
following the Sec.  33.87(f) tests.
    Therefore, we are proposing an in-service evaluation program in the 
ALS to obtain relevant data concerning the condition of hardware and 
power availability at various stages in the life of the engine. The 
data should be compared with corresponding data observed during 
certification that defined the post-flight inspection and maintenance 
actions. If the data obtained from the in-service program indicates 
that the in-service differences are not properly accounted for, then 
this data should be used to modify the instructions as appropriate. To 
achieve the objectives of the program, the engine manufacturer must 
ensure that operators understand and are aware of the need for the 
procedures to properly collect and return information needed by the 
manufacturer.

Rulemaking Analyses and Notices

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

[[Page 25211]]

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 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 
rotorcraft engine OEI ratings.

Paperwork Reduction Act

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

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 
determined there are no ICAO Standards and Recommended Practices that 
correspond to these proposed regulations.

Executive Order 12866 and DOT Regulatory Policies and Procedures

    Executive Order 12866, ``Regulatory Planning and Review,'' dated 
September 30, 1993 (58 FR 51736) directs the FAA to assess both the 
costs and the benefits of a regulatory change. We are not allowed to 
propose or adopt a regulation unless we make a reasoned determination 
that the benefits of the intended regulation justify the costs. Our 
assessment of this rulemaking indicates that its economic impact is 
minimal because U.S. turbine rotorcraft manufacturers are already 
manufacturing rotorcraft turbine engines according to European 
requirements that are equivalent to these proposed requirements. 
Because the costs and benefits of this action do not make it a 
``significant regulatory action'' as defined in the Order, we have not 
prepared a ``regulatory evaluation,'' which is the written cost/benefit 
analysis ordinarily required for all rulemaking under the DOT 
Regulatory Policies and Procedures. We do not need to do a full 
evaluation where the economic impact of a rule is minimal.

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

    Proposed changes to Federal regulations must undergo several 
economic analyses. First, Executive Order 12866 directs that each 
Federal agency propose or adopt a regulation only upon a 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 also requires agencies to consider 
international standards and, where appropriate, use them as 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 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.
    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 proposed rule. The 
reasoning for this determination follows.
    This proposed rule harmonizes FAA airworthiness standards for the 
30-second and 2-minute OEI ratings with similar requirements already 
adopted by EASA and being processed by Transport Canada. Because the 
OEI ratings are optional, manufacturers will provide this capability 
only if they expect to recover any additional costs in the marketplace. 
The FAA estimates that this rule would affect 8 engine models, 
approximately 100 helicopters, and that there would be approximately 3 
OEI events per year. The total estimated cost of the proposed rule over 
20 years is approximately $619,000 in present value cost (in 2005 
dollars). These optional costs would only be incurred if the 
manufacturer believes the enhanced capability benefits exceed the 
costs. The FAA has not attempted to quantify the cost savings that may 
accrue due to harmonization of this rule, beyond noting that they 
contribute to a large potential harmonization savings. Safety after an 
engine failure or shutdown under this rule would be at least equivalent 
to operational safety under the previous regulations.
    The FAA finds that the expected outcome of the proposed rule would 
have a minimal impact with positive net benefits, and, therefore, we 
did not prepare a full regulatory evaluation. The FAA requests comments 
with supporting justification about our determination of minimal 
impact. The FAA has, therefore, determined that this proposed rule is 
not a ``significant regulatory action'' as defined in section 3(f) of 
Executive Order 12866, and is not ``significant'' as defined in DOT's 
Regulatory Policies and Procedures.

Regulatory Flexibility Act

    The Regulatory Flexibility Act (RFA) of 1980 (Pub. L. 96-354) 
directs the FAA to fit regulatory requirements to the scale of the 
businesses, organizations, and governmental jurisdictions subject to 
the regulation. We are required to determine whether a proposed or 
final action will have a ``significant economic impact on a substantial 
number of small entities'' as they are defined in the Act. If we find 
the action will have a significant impact, we must do a ``regulatory 
flexibility analysis.''
    However, if an agency determines that a proposed 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.
    All U.S. multi-turbine engine rotorcraft manufacturers exceed the 
Small Business Administration small-entity criteria of 1,500 employees 
for aircraft manufacturers. Currently manufactured U.S. twin-turbine 
engine rotorcraft type certificate holders include: Bell Helicopter 
Textron, Sikorsky Aircraft Corporation, and MD Helicopters, Inc. In 
addition, all of the U.S. rotorcraft engine manufacturers exceed the 
Small Business

[[Page 25212]]

Administration small-entity criteria of 1,000 employees for aircraft 
engine manufacturers. There are four U.S. engine manufacturers that 
produce turbine engines for rotorcraft: (1) General Electric, GE 
Transportation, (2) Rolls-Royce Allison, Allison Engines, Inc., (3) 
Light Helicopter Turbine Engine Company (a partnership of Rolls-Royce 
and Honeywell), and (4) Honeywell International, Inc. Given that there 
are no small-entity manufacturers of twin-engine rotorcraft or of 
rotorcraft engines and the rule would impose only minimal costs, the 
FAA certifies that this proposed rule would not have a significant 
economic impact on a substantial number of small entities. The FAA 
invites comments regarding this determination.

International Trade Impact Assessment

    The Trade Agreements Act of 1979 (Pub. L. 96-39) prohibits Federal 
agencies from establishing any standards or engaging in related 
activities that create unnecessary obstacles to the foreign commerce of 
the United States. Legitimate domestic objectives, such as safety, are 
not considered unnecessary obstacles. 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 rulemaking and has determined that it uses the 
European international standards as the regulation basis and is in 
accord 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 a $100 million or more expenditure 
(adjusted annually for inflation with the base year 1995) 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 
regulatory action.'' The FAA currently uses an inflation-adjusted value 
of $128.1 million in lieu of $100 million.
    This proposed rule does not contain such a mandate. The 
requirements of Title II of the Act, therefore, do not apply.

Executive Order 13132, Federalism

    The FAA 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.

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

Regulations That Significantly Affect Energy Supply, Distribution, or 
Use

    The FAA analyzed this NPRM under Executive Order 13211, Actions 
Concerning Regulations that Significantly Affect Energy Supply, 
Distribution, or Use (May 18, 2001). We determined that it is not a 
``significant energy action'' under the executive order because it is 
not a ``significant regulatory action'' under Executive Order 12866, 
and it is not likely to have a significant adverse effect on the 
supply, distribution, or use of energy.

List of Subjects

14 CFR Part 1

    Air transportation, Aircraft, Aviation safety, Engines, 
Helicopters, Ratings, Rotorcraft, Safety.

14 CFR Part 33

    Air transportation, Aircraft, Aviation safety, Engines, Ratings, 
Rotorcraft, Safety.

The Proposed Amendment

    In consideration of the foregoing, the Federal Aviation 
Administration proposes to amend parts 1 and 33 of Title 14, Code of 
Federal Regulations as follows:

PART 1--DEFINITIONS AND ABBREVIATIONS

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

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

    2. Amend Sec.  1.1 by revising the definitions for ``Rated 30-
second OEI power,'' ``Rated 2-minute OEI power,'' ``Rated continuous 
OEI power,'' ``Rated 30-minute OEI power,'' and ``Rated 2\1/2\-minute 
OEI power,'' to read as follows:


Sec.  1.1  General definitions.

* * * * *
    Rated 30-second OEI Power, with respect to rotorcraft turbine 
engines, means the approved brake horsepower developed under static 
conditions at specified altitudes and temperatures within the operating 
limitations established for the engine under Part 33 of this chapter, 
for continuation of one flight operation after the failure or shutdown 
of one engine in multiengine rotorcraft, for up to three periods of use 
no longer than 30 seconds each in any one flight, and followed by 
mandatory inspection and prescribed maintenance action.
    Rated 2-minute OEI Power, with respect to rotorcraft turbine 
engines, means the approved brake horsepower developed under static 
conditions at specified altitudes and temperatures within the operating 
limitations established for the engine under Part 33 of this chapter, 
for continuation of one flight operation after the failure or shutdown 
of one engine in multiengine rotorcraft, for up to three periods of use 
no longer than 2 minutes each in any one flight, and followed by 
mandatory inspection and prescribed maintenance action.
    Rated continuous OEI power, with respect to rotorcraft turbine 
engines, means the approved brake horsepower developed under static 
conditions at specified altitudes and temperatures within the operating 
limitations established for the engine under Part 33 of this chapter, 
and limited in use to the time required to complete the flight after 
the failure or shutdown of one engine of a multiengine rotorcraft.
* * * * *
    Rated 30-minute OEI power, with respect to rotorcraft turbine 
engines, means the approved brake horsepower developed under static 
conditions at specified altitudes and temperatures within the operating 
limitations established for the engine under Part 33 of this chapter, 
and limited in use to one period of use no longer than 30 minutes after 
the failure or shutdown of one engine of a multiengine rotorcraft.
    Rated 2\1/2\-minute OEI power, with respect to rotorcraft turbine 
engines, means the approved brake horsepower developed under static 
conditions at specified altitudes and temperatures within the operating 
limitations established for the engine under Part 33 of this chapter 
for periods of use no longer than 2\1/2\ minutes each after the failure 
or shutdown of one engine of a multiengine rotorcraft.
* * * * *

[[Page 25213]]

PART 33--AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES

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

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

    4. Amend Sec.  33.5 to add a new paragraph (b)(4) to read as 
follows:


Sec.  33.5  Instruction manual for installing and operating the engine.

* * * * *
    (b) * * *
    (4) For rotorcraft engines having one or more OEI ratings, 
applicants must provide data on engine performance characteristics and 
variability to enable the aircraft manufacturer to establish aircraft 
power assurance procedures.

    5. Amend Sec.  33.29 by revising paragraph (c) and adding paragraph 
(d) to read as follows:


Sec.  33.29  Instrument connection.

* * * * *
    (c) Each rotorcraft turbine engine having a 30-second OEI rating 
and a 2-minute OEI rating must have a means or a provision for a means 
to:
    (1) Alert the pilot when the engine is at the 30-second OEI and the 
2-minute OEI power levels, when the event begins, and when the time 
interval expires;
    (2) Automatically record each usage and duration of power at the 
30-second OEI and 2-minute OEI levels;
    (3) Alert maintenance personnel in a positive manner that the 
engine has been operated at either or both of the 30-second and 2-
minute OEI power levels, and permit retrieval of the recorded data; and
    (4) Enable routine verification of the proper operation of the 
above means.
    (d) The means, or the provision for a means, of paragraph (c) of 
this section must not be capable of being reset in flight.

    6. Revise Sec.  33.67(d) to read as follows:


Sec.  33.67  Fuel system.

* * * * *
    (d) Rotorcraft engines having a 30-second OEI rating must 
incorporate a means, or a provision for a means, for automatic 
availability and automatic control of the 30-second OEI power within 
its operating limitations.
    7. Amend Sec.  33.87 by redesignating paragraphs (c)(2), (c)(4), 
(c)(5), and (c)(6) as paragraphs (c)(4), (c)(5), (c)(6), and (c)(7) 
respectively, by adding new paragraph (c)(2), and by revising 
paragraphs (a)(5), (a)(6), (c)(3), newly redesignated paragraphs (c)(4) 
through (c)(7), (f) introductory text, (f)(4) and (f)(8) to read as 
follows:


Sec.  33.87  Endurance test.

    (a) * * *
    (5) Maximum air bleed for engine and aircraft services must be used 
during at least one-fifth of the runs, except for the final 120-minute 
test required under paragraph (f) of this section, provided the 
validity of the test is not compromised. However, for these runs, the 
power or thrust or the rotor shaft rotational speed may be less than 
100 percent of the value associated with the particular operation being 
tested if the FAA finds that the validity of the endurance test is not 
compromised.
    (6) Each accessory drive and mounting attachment must be loaded in 
accordance with paragraphs (a)(6)(i) and (ii) of this section, except 
as permitted by paragraph (a)(6)(iii) of this section for the final 
120-minute test required under paragraph (f) of this section.
    (i) The load imposed by each accessory used only for aircraft 
service must be the limit load specified by the applicant for the 
engine drive and attachment point during rated maximum continuous power 
or thrust and higher output.
    (ii) The endurance test of any accessory drive and mounting 
attachment under load may be accomplished on a separate rig if the 
validity of the test is confirmed by an approved analysis.
    (iii) The applicant is not required to load the accessory drives 
and mounting attachments when running the tests under paragraphs (f)(1) 
through (f)(8) of this section if the applicant can substantiate that 
there is no significant effect on the durability of any accessory drive 
or engine component. However, the applicant must add the equivalent 
engine output power extraction from the power turbine rotor assembly to 
the engine shaft output.
* * * * *
    (c) * * *
    (2) Rated maximum continuous and takeoff power. Thirty minutes at--
    (i) Rated maximum continuous power during fifteen of the twenty-
five 6-hour endurance test cycles; and
    (ii) Rated takeoff power during ten of the twenty-five 6-hour 
endurance test cycles.
    (3) Rated maximum continuous power. One hour at rated maximum 
continuous power.
    (4) Rated 30-minute OEI power. Thirty minutes at rated 30-minute 
OEI power.
    (5) Incremental cruise power. Two hours and 30 minutes at the 
successive power lever positions corresponding with not less than 15 
approximately equal speed and time increments between maximum 
continuous engine rotational speed and ground or minimum idle 
rotational speed. For engines operating at constant speed, power may be 
varied in place of speed. If there are significant peak vibrations 
anywhere between ground idle and maximum continuous conditions, the 
number of increments chosen must be changed to increase the amount of 
running conducted while subject to peak vibrations up to not more than 
50 percent of the total time spent in incremental running.
    (6) Acceleration and deceleration runs. Thirty minutes of 
accelerations and decelerations, consisting of six cycles from idling 
power to rated takeoff power and maintained at the takeoff power lever 
position for 30 seconds and at the idling power lever position for 
approximately 4\1/2\ minutes. In complying with this paragraph, the 
power control lever must be moved from one extreme position to the 
other in not more than one second. If, however, different regimes of 
control operations are incorporated that necessitate scheduling of the 
power control lever motion from one extreme position to the other, then 
a longer period of time is acceptable, but not more than 2 seconds.
    (7) Starts. One hundred starts, of which 25 starts must be preceded 
by at least a two-hour engine shutdown. There must be at least 10 false 
engine starts, pausing for the applicant's specified minimum fuel 
drainage time, before attempting a normal start. There must be at least 
10 normal restarts not more than 15 minutes after engine shutdown. The 
remaining starts may be made after completing the 150 hours of 
endurance testing.
* * * * *
    (f) Rotorcraft Engines for which 30-second OEI and 2-minute OEI 
ratings are desired. For each rotorcraft engine for which 30-second OEI 
and 2-minute OEI power ratings are desired, and following completion of 
the tests under paragraphs (b), (c), (d), or (e) of this section, the 
applicant may disassemble the tested engine to the extent necessary to 
show compliance with the requirements of Sec.  33.93(a). The tested 
engine must then be reassembled using the same parts used during the 
test runs of paragraphs (b), (c), (d), or (e) of this section, except 
those parts described as consumables in the Instructions for Continued 
Airworthiness. Additionally, the tests required in paragraphs (f)(1) 
through (f)(7) of this section must be run continuously. If a stop 
occurs during these tests, the interrupted sequence must be repeated 
unless the applicant shows that the severity of the test would

[[Page 25214]]

not be reduced if it were continued. The applicant must conduct the 
following test sequence four times, for a total time of not less than 
120 minutes:
* * * * *
    (4) 30-minute OEI power, continuous OEI power, or maximum 
continuous power. Five minutes at whichever is the greatest of rated 
30-minute OEI power, rated continuous OEI power, or rated maximum 
continuous power, except that, during the first test sequence, this 
period shall be 65 minutes. However, where the greatest rating power is 
30-minute OEI power, that sixty-five minute period shall consist of 30 
minutes at 30-minute OEI power followed by 35 minutes at whichever is 
the greater of continuous OEI power or maximum continuous power.
* * * * *
    (8) Idle. One minute at flight idle.
* * * * *
    8. Amend Sec.  33.88 by removing paragraph (b), redesignating (c) 
and (d) as paragraphs (b) and (c), respectively; and revising the text 
of the paragraph (a) and the new paragraph (b) to read as follows:


Sec.  33.88  Engine overtemperature test.

    (a) In addition to the test requirements for the ratings as 
provided in paragraph (b) of this section, each engine must run for 5 
minutes at maximum permissible rpm with the gas temperature at least 75 
[deg]F (42 [deg]C) higher than the maximum rating's steady-state 
operating limit. Following this run, the turbine assembly must be 
within serviceable limits.
    (b) Each engine for which 30-second OEI and 2-minute OEI ratings 
are desired, that incorporates a means for automatic temperature 
control within its operating limitations in accordance with Sec.  
33.67(d), must run for a period of 4 minutes at the maximum power-on 
rpm with the gas temperature at least 35 [deg]F (19 [deg]C) higher than 
the maximum operating limit at 30-second OEI rating. Following this 
run, the turbine assembly may exhibit distress beyond the limits for an 
overtemperature condition provided the engine is shown by analysis or 
test, as found necessary by the FAA, to maintain the integrity of the 
turbine assembly.
* * * * *
    9. Revise Sec.  33.93(b)(2) to read as follows:


Sec.  33.93  Teardown inspection.

* * * * *
    (b) * * *
    (2) Each engine may exhibit deterioration in excess of that 
permitted in paragraph (a)(2) of this section, including some engine 
parts or components that may be unsuitable for further use. The 
applicant must show by inspection, analysis, test, or by any 
combination thereof as found necessary by the FAA, that structural 
integrity of the engine is maintained; or
* * * * *
    10. Amend Appendix A to part 33 by revising A33.4 to read as 
follows:

Appendix A to Part 33--Instructions for Continued Airworthiness

* * * * *

A33.4 AIRWORTHINESS LIMITATIONS SECTION

    The Instructions for Continued Airworthiness must contain a 
section titled Airworthiness Limitations that is segregated and 
clearly distinguishable from the rest of the manual.
    (a) For all engines:
    (1) The Airworthiness Limitations section must set forth each 
mandatory replacement time, inspection interval, and related 
procedure required for type certification. If the Instructions for 
Continued Airworthiness consist of multiple documents, the section 
required under this paragraph must be included in the principal 
manual.
    (2) This section must contain a legible statement in a prominent 
location that reads: ``The Airworthiness Limitations section is FAA 
approved and specifies maintenance required under Sec. Sec.  43.16 
and 91.403 of Title 14 of the Code of Federal Regulations unless an 
alternative program has been FAA approved.''
    (b) For rotorcraft engines having 30-second OEI and 2-minute OEI 
ratings:
    (1) The Airworthiness Limitations section must also prescribe 
the mandatory post-flight inspections and maintenance actions 
associated with any use of either 30-second OEI or 2-minute OEI 
ratings. The applicant must validate the adequacy of these 
inspections and maintenance actions; and
    (2) The applicant must establish an in-service engine evaluation 
program to ensure the continued adequacy of the data for Sec.  
33.5(b)(4) pertaining to power availability and the adequacy of the 
instructions for mandatory post flight inspection and maintenance 
actions. The program must include service engine tests or equivalent 
service engine test experience on engines of similar design and 
evaluations of service usage of the 30-second OEI or 2-minute OEI 
ratings.

    Issued in Washington, DC, on April 13, 2007.
John J. Hickey,
Director, Aircraft Certification Service.

 [FR Doc. E7-7943 Filed 5-3-07; 8:45 am]
BILLING CODE 4910-13-P