[Federal Register Volume 70, Number 221 (Thursday, November 17, 2005)]
[Rules and Regulations]
[Pages 69664-69687]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-22704]


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

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 87

[OAR-2002-0030; FRL-7997-3]
RIN 2060-AK01


Control of Air Pollution From Aircraft and Aircraft Engines; 
Emission Standards and Test Procedures

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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

SUMMARY: In this action, we are amending the existing United States 
regulations governing the exhaust emissions from new commercial 
aircraft gas turbine engines. Under the authority of section 231 of the 
Clean Air Act (CAA), 42 U.S.C. 7571, the Environmental Protection 
Agency (EPA) is establishing new emission standards for oxides of 
nitrogen (NO<INF>X</INF>) for newly certified commercial aircraft gas 
turbine engines with rated thrust greater than 26.7 kilonewtons (kN). 
This action adopts standards equivalent to the NO<INF>X</INF> standards 
of the United Nations International Civil Aviation Organization (ICAO), 
and thereby brings the United States emission standards into alignment 
with the internationally adopted standards (ICAO standards for newly 
certified engines were effective beginning in 2004). In addition, 
today's action amends the test procedures for gaseous exhaust emissions 
to correspond to recent amendments to the ICAO test procedures for 
these emissions.
    On December 19, 2005, the new NO<INF>X</INF> standards will apply 
to newly certified gas turbine engines--those engines designed and 
certified after the effective date of the regulations (for purposes of 
this action, the date of manufacture of the first individual production 
model means the date of type certification). Newly manufactured engines 
of already certified models (i.e., those individual engines that are 
part of an already certified engine model, but are built after the 
effective date of the regulations for such engines and have never been 
in service) will not have to meet these standards.
    Today's amendments to the emission test procedures are those 
recommended by ICAO and are widely used by the aircraft engine 
industry. Thus, today's action will help establish consistency between 
U.S. and international standards, requirements, and test procedures. 
Since aircraft and aircraft engines are international commodities, 
there is commercial benefit to consistency between U.S. and 
international emission standards and control program requirements. In 
addition, today's action ensures that domestic commercial aircraft meet 
the current international standards, and thus, the public can be 
assured they are receiving the air quality benefits of the 
international standards.

DATES: This final rule is effective December 19, 2005.
    The incorporation by reference of certain publications listed in 
this regulation is approved by the Director of the Federal Register as 
of December 19, 2005.

ADDRESSES: EPA has established a docket for this action under Docket ID 
No. OAR-2002-0030. All documents in the docket are listed in the 
EDOCKET index at http://www.epa.gov/edocket. Although listed in the 
index, some information is not publicly available,

[[Page 69665]]

i.e., CBI or other information whose disclosure is restricted by 
statute. Certain other material, such as copyrighted material, is not 
placed on the Internet and will be publicly available only in hard copy 
form. Publicly available docket materials are available either 
electronically in EDOCKET or in hard copy at the Air Docket in the EPA 
Docket Center, EPA/DC, EPA West, Room B102, 1301 Constitution Ave., 
NW., Washington, DC. The Public Reading Room is open from 8:30 a.m. to 
4:30 p.m., Monday through Friday, excluding legal holidays. The 
telephone number for the Public Reading Room is (202) 566-1744, and the 
telephone number for the Air Docket is (202) 566-1742.

FOR FURTHER INFORMATION CONTACT: Mr. Bryan Manning, Assessment and 
Standards Division, Office of Transportation and Air Quality, 
Environmental Protection Agency, 2000 Traverwood Drive, Ann Arbor, MI 
48105; telephone number: (734) 214-4832; fax number: (734) 214-4816; e-
mail address: <a href="/cdn-cgi/l/email-protection#b5d8d4dbdbdcdbd29bd7c7ccd4dbf5d0c5d49bd2dac3"><span class="__cf_email__" data-cfemail="86ebe7e8e8efe8e1a8e4f4ffe7e8c6e3f6e7a8e1e9f0">[email protected]</span></a>, or Assessment and Standards 
Division Hotline; telephone number: (734) 214-4636; e-mail address: 
<a href="/cdn-cgi/l/email-protection#442537202d2a222b042134256a232b32"><span class="__cf_email__" data-cfemail="82e3f1e6ebece4edc2e7f2e3ace5edf4">[email protected]</span></a>.

SUPPLEMENTARY INFORMATION:

Does This Action Apply to Me?

    Entities potentially regulated by this action are those that 
manufacture and sell commercial aircraft engines and aircraft in the 
United States. Regulated categories include:

----------------------------------------------------------------------------------------------------------------
                                                                               Examples of potentially affected
                  Category                    NAICS a codes    SIC codes b                 entities
----------------------------------------------------------------------------------------------------------------
Industry...................................          336412            3724  Manufacturers of new aircraft
                                                                              engines.
Industry...................................          336411            3721  Manufacturers of new aircraft.
----------------------------------------------------------------------------------------------------------------
a North American Industry Classification System (NAICS).
b Standard Industrial Classification (SIC) system code.

    This table is not intended to be exhaustive, but rather provides a 
guide for readers regarding entities likely to be regulated by this 
action. This table lists the types of entities that EPA is now aware 
could potentially be regulated by this action. Other types of entities 
not listed in the table could also be regulated. To determine whether 
your activities are regulated by this action, you should carefully 
examine the applicability criteria in 40 CFR 87.20 (part 87). If you 
have any questions regarding the applicability of this action to a 
particular entity, consult the person listed in the preceding FOR 
FURTHER INFORMATION CONTACT section.

How Can I Get Copies of This Document and Other Related Information?

    Docket. EPA has established an official public docket for this 
action under Docket ID No. OAR-2002-0030 at http://www.epa.gov/edocket. 
The official public docket consists of the documents specifically 
referenced in this action, any public comments received, and other 
information related to this action. The public docket does not include 
Confidential Business Information (CBI) or other information whose 
disclosure is restricted by statute. The official public docket is the 
collection of materials that is available for public viewing at the Air 
Docket in the EPA Docket Center, (EPA/DC) EPA West, Room B102, 1301 
Constitution Ave., NW., Washington, DC. The EPA Docket Center Public 
Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through 
Friday, excluding legal holidays. The telephone number for the Reading 
Room is (202) 566-1742, and the telephone number for the Air Docket is 
(202) 566-1742.
    Electronic Access. You may access this Federal Register document 
electronically through the EPA Internet under the ``Federal Register'' 
listings at http://www.epa.gov/fedrgstr/.
    An electronic version of the public docket is available through 
EPA's electronic public docket and comment system, EPA Dockets. You may 
use EPA Dockets at http://www.epa.gov/edocket/ to view public comments, 
access the index listing of the contents of the official public docket, 
and to access those documents in the public docket that are available 
electronically. Although not all docket materials may be available 
electronically, you may still access any of the publicly available 
docket materials through the docket facility identified above. Once in 
the system, select ``search,'' then key in the appropriate docket 
identification number.

Outline of This Preamble

I. Introduction
    A. Brief History of EPA's Regulation of Aircraft Engine 
Emissions
    B. Interaction With the International Community
    C. EPA's Responsibilities Under the Clean Air Act
II. Why is EPA Taking This Action?
    A. Inventory Contribution
    B. Health and Welfare Effects
    1. Ozone
    a. What Are the Health Effects of Ozone Pollution?
    b. What Are the Current and Projected 8-hour Ozone Levels?
    2. Particulate Matter
    a. What Is Particulate Matter?
    b. What Are the Health Effects of PM<INF>2.5</INF>?
    c. What Are Current and Projected Level of PM?
    C. Other Environmental Effects
    1. Acid Deposition
    2. Eutrophication and Nitrification
    3. Plant Damage from Ozone
    4. Visibility
III. Aircraft Engine Standards
    A. What Are The NO<INF>X</INF> Standards For Newly Certified 
Engines?
    1. Today's NO<INF>X</INF> Standards
    a. For Engines With a Pressure Ratio of 30 or less
    i. For engines with a maximum rated output of more than 89.0 kN
    ii. For engines with a maximum rated output of more than 26.7 kN 
but not more than 89.0 kN
    b. For Engines With A Pressure Ratio of More Than 30 But Less 
than 62.5
    i. For engines with a maximum rated output of more than 89.0 kN
    ii. For engines with a maximum rated output of more than 26.7 kN 
but not more than 89.0 kN
    c. For Engines With a Pressure Ratio of 62.5 or More
    2. NO<INF>X</INF> Standards of Newly Certified Mid- and High-
Thrust Engines
    3. NO<INF>X</INF> Standards for Newly Certified Low-Thrust 
Engines
    4. Rationale for Today's NO<INF>X</INF> Standards for Newly 
Certified Low-, Mid-, and High-Thrust Engines
    5. Future NO<INF>X</INF> Standards for Newly Certified Low-, 
Mid-, and High-Thrust Engines
    B. Newly Manufactured Engines of Already Certified Models
    1. What Is the Status of Engines?
    2. What Are The Issues With Applying Today's NO<INF>X</INF> 
Standards to Newly Manufactured Engines of Already Certified Models?
IV. Amendments to Criteria on Calibration and Test Gases for Gaseous 
Emissions Test and Measurement Procedures
V. Correction of Exemptions for Very Low Production Models
VI. Coordination with FAA
VII. Possible Future Aviation Emissions Reduction (EPA/FAA Voluntary 
Aviation Emissions Reduction Initiative)
VIII. Regulatory Impacts
IX. Public Participation
X. Statutory Provisions and Legal Authority
XI. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review

[[Page 69666]]

    B. Paperwork Reduction Act
    C. Regulatory Flexibility Analysis
    D. Unfunded Mandates Reform Act
    E. Executive Order 13132: Federalism
    F. Executive Order 13175: Consultation and Coordination With 
Indian Tribal Governments
    G. Executive Order 13045: Protection of Children from 
Environmental Health & Safety Risks
    H. Executive Order 13211: Actions That Significantly Affect 
Energy Supply, Distribution, or Use
    I. National Technology Transfer Advancement Act
    J. Congressional Review Act

I. Introduction

A. Brief History of EPA's Regulation of Aircraft Engine Emissions

    Section 231(a)(2)(A) of the Clean Air Act (CAA) directs the EPA 
Administrator to ``issue proposed emission standards applicable to the 
emission of any air pollutant from any class or classes of aircraft or 
aircraft engines which in his judgment causes, or contributes to, air 
pollution which may reasonably be anticipated to endanger public health 
or welfare.'' 42 U.S.C. 7571(a)(2)(A). In addition, section 231(a)(3) 
provides that after we propose standards, the Administrator shall issue 
such standards ``with such modifications as he deems appropriate.'' 42 
U.S.C. 7571(a)(3). Under this authority EPA has conducted several 
rulemakings since 1973 establishing emission standards and related 
requirements for several classes (commercial and general aviation 
engines) of aircraft and aircraft engines. Most recently, in 1997 EPA 
promulgated NO<INF>X</INF> emission standards for newly manufactured 
gas turbine engines of already certified models \1\ (those individual 
engines that are part of an already certified engine model, but are 
built after the effective date of the regulations for such engines and 
have never been in service) \2\ and for newly certified gas turbine 
engines (those engines designed and certified after the effective date 
of the regulations \3\).\4\ In addition, EPA promulgated a carbon 
monoxide (CO) emission standard for newly manufactured gas turbine 
engines in this same 1997 rulemaking. At the time, the 1997 rulemaking 
established consistency between the U.S. and international standards. 
(See 40 CFR part 87 for a description of EPA's aircraft engine emission 
control requirements and 14 CFR part 34 for the Department of 
Transportation's regulations for ensuring compliance with these 
standards in accordance with section 232 of the Clean Air Act.)
---------------------------------------------------------------------------

    \1\ In the proposal, we referred to such engines as already 
certified, newly manufactured engines or already certified engines; 
however, this terminology may need some clarification for the final 
rulemaking (thus, we use the term ``newly manufactured engines of 
already certified models'').
    \2\ This does not mean that in 1997 we promulgated requirements 
for the re-certification or retrofit of existing in-use engines.
    \3\ Throughout this rule, the date of manufacture of the first 
individual production model means the date of type certification.
    \4\ U.S. EPA, ``Control of Air Pollution from Aircraft and 
Aircraft Engines; Emission Standards and Test Procedures;'' Final 
Rule, 62 FR 25356, May 8, 1997.
---------------------------------------------------------------------------

B. Interaction With the International Community

    Since publication of the initial standards in 1973, EPA, together 
with the Federal Aviation Administration (FAA), has worked with the 
International Civil Aviation Organization (ICAO) on the development of 
international aircraft engine emission standards. ICAO was established 
in 1944 by the United Nations (by the Convention on International Civil 
Aviation, the ``Chicago Convention'') ``* * * in order that 
international civil aviation may be developed in a safe and orderly 
manner and that international air transport services may be established 
on the basis of equality of opportunity and operated soundly and 
economically.'' \5\ ICAO's responsibilities include developing aircraft 
technical and operating standards, recommending practices, and 
generally fostering the growth of international civil aviation.
---------------------------------------------------------------------------

    \5\ ICAO, ``Convention on International Civil Aviation,'' Sixth 
Edition, Document 7300/6, 1980. Copies of this document can be 
obtained from the ICAO Web site located at http://www.icao.int.
---------------------------------------------------------------------------

    In 1972 at the United Nations Conference on the Human Environment, 
ICAO's position on the human environment was developed to be the 
following: ``[i]n fulfilling this role ICAO is conscious of the adverse 
environmental impact that may be related to aircraft activity and its 
responsibility and that of its member States to achieve maximum 
compatibility between the safe and orderly development of civil 
aviation and the quality of the human environment.'' Also, in 1972 ICAO 
established the position to continue ``* * * with the assistance and 
cooperation of other bodies of the Organization and other international 
organizations * * * the work related to the development of Standards, 
Recommended Practices and Procedures and/or guidance material dealing 
with the quality of the human environment * * *.'' \6\ At the 35th 
Assembly in October 2004, ICAO's 188 Contracting States affirmed that 
ICAO should continue to take the leadership role in all international 
civil aviation matters relating to the environment.\7\
---------------------------------------------------------------------------

    \6\ International Civil Aviation Organization (ICAO), Foreword 
of ``Aircraft Engine Emissions,'' International Standards and 
Recommended Practices, Environmental Protection, Annex 16, Volume 
II, Second Edition, July 1993. Copies of this document can be 
obtained from the ICAO Web site located at http://www.icao.int.
    \7\ ICAO, ``Assembly--35th Session, Report of the Executive 
Committee on Agenda Item 15,'' Presented by the Chairman of the 
Executive Committee, A35-WP/32, October 12, 2004.
---------------------------------------------------------------------------

    The United States is one of 188 participating member States of 
ICAO.\8\ Under the basic ICAO treaty established in 1944 (the Chicago 
Convention), a participating nation which elects not to adopt the ICAO 
standards must provide a written explanation to ICAO describing why a 
given standard is impractical to comply with or not in its national 
interest.\9\ ICAO standards require States to provide written 
notification and failure to provide such notification could have 
negative consequences as detailed below.
---------------------------------------------------------------------------

    \8\ As of March 2, 2005 there were 188 Contracting States 
according to the ICAO Web site located at http://www.icao.int.
    \9\ Text of Article 38 of Chicago Convention:
    Any State which finds it impracticable to comply in all respects 
with any such international standard or procedure, or to bring its 
own regulations or practices into full accord with any international 
standard or procedure after amendment of the latter, or which deems 
it necessary to adopt regulations or practices differing in any 
particular respect from those established by an international 
standard, shall give immediate notification to the International 
Civil Aviation Organization of the differences between its own 
practice and that established by the international standard * * * In 
any such case, the Council shall make immediate notification to all 
other states of the difference which exists between one or more 
features of an international standard and the corresponding national 
practice of that State.
---------------------------------------------------------------------------

    If a Contracting State files a written notification indicating that 
it does not meet ICAO standards, other Contracting States are absolved 
of their obligations to ``recognize as valid'' the certificate of 
airworthiness issued by that Contracting State, since that certificate 
will not have been issued under standards ``equal to or above'' ICAO 
standards. In other words, other Contracting States do not have to 
allow aircraft belonging to that Contracting State to travel through 
their airspace.\10\ Further, if it fails to file a written 
notification, it will be in default of its obligations, and risks 
mandatory exclusion of its aircraft from the airspace of other 
Contracting States and

[[Page 69667]]

the loss of its voting power in the Assembly and Council.\11\
---------------------------------------------------------------------------

    \10\ Text of Article 33 of Chicago Convention:
    Certificates of airworthiness and certificates of competency and 
licenses issued or rendered valid by the contracting State in which 
the aircraft is registered, shall be recognized as valid by the 
other contracting States, provided that the requirements under which 
such certificates or licenses were issued or rendered valid are 
equal to or above the minimum standards which may be established 
from time to time pursuant to this Convention.
    \11\ Articles 87 and 88 of Chicago Convention.
---------------------------------------------------------------------------

    The Chicago Convention does not require all Contracting States to 
adopt identical airworthiness standards. Although the Convention urges 
a high degree of uniformity, it is expected that States will adopt 
their own airworthiness standards, and it is anticipated that some 
states may adopt standards that are more stringent than those agreed 
upon by ICAO. However, because any State can ban use within its 
airspace of any aircraft that does not meet ICAO standards, States that 
wish to use aircraft in international air transportation have agreed to 
adopt standards that meet or exceed the stringency levels of ICAO 
standards.\12\ Because States are required to recognize certificates of 
any State whose standards meet or exceed ICAO standards, a State is 
assured its aircraft will be permitted to operate in any other 
Contracting State if its standards meet or exceed the minimum 
stringency levels of ICAO standards.
---------------------------------------------------------------------------

    \12\ Article 33 of Chicago Convention.
---------------------------------------------------------------------------

    As long as a participating nation of ICAO adopts aircraft emission 
standards that are equal to or more stringent than ICAO's standards, 
the certificates of airworthiness for such nations are valid. Thus, 
aircraft belonging to countries with more stringent standards are 
permitted to travel through the airspace of other countries without any 
restriction. To ensure operation internationally without constraints, a 
participating nation which elects to adopt more stringent standards is 
obligated to notify ICAO of the differences between its standards and 
ICAO standards.\13\ However, if a nation sets tighter standards than 
ICAO, air carriers not based in that nation (foreign-flag carriers) 
would only be required to comply with the ICAO standards.
---------------------------------------------------------------------------

    \13\ Article 38 of Chicago Convention.
---------------------------------------------------------------------------

    The ICAO Council's Committee on Aviation Environmental Protection 
(CAEP) undertakes ICAO's technical work in the environmental field. The 
CAEP is responsible for evaluating, researching, and recommending 
measures to the ICAO Council that address the environmental impact of 
international civil aviation. CAEP is composed of various Study Groups, 
Work Groups, Committees and other contributing memberships that include 
atmospheric, economic, aviation, environmental, and other professionals 
committed to ICAO's previously stated position regarding aviation and 
the environment. At CAEP meetings, the United States is represented by 
the FAA, which plays an active role at these meetings (see section VI 
for further discussion of FAA's role). EPA has historically been a 
principal participant in the development of U.S. policy in ICAO/CAEP 
and other international venues, assisting and technically advising FAA 
on aviation emissions matters. If the ICAO Council adopts a CAEP 
proposal to adopt a new environmental standard, it then becomes part of 
the ICAO standards and recommended practices (Annex 16 to the Chicago 
Convention).\14\
---------------------------------------------------------------------------

    \14\ ICAO, ``Aircraft Engine Emissions,'' International 
Standards and Recommended Practices, Environmental Protection, Annex 
16, Volume II, Second Edition, July 1993. Copies of this document 
can be obtained from ICAO (http://www.icao.int).
---------------------------------------------------------------------------

    On June 30, 1981, the ICAO Council adopted its first international 
standards and recommended practices covering aircraft engine 
emissions.\15\ These standards limit aircraft engine emissions of 
NO<INF>X</INF>, CO, and hydrocarbons (HC), in relation to other engine 
performance parameters, and are commonly known as stringency standards. 
On March 24, 1993, the ICAO Council approved a proposal adopted at the 
second meeting of the CAEP (CAEP/2) to tighten the original 
NO<INF>X</INF> standard by 20 percent and amend the test procedures. At 
the next CAEP meeting (CAEP/3) in December 1995, the CAEP recommended a 
further tightening of 16 percent and additional test procedure 
amendments, but on March 20, 1997 the ICAO Council rejected this 
stringency proposal and approved only the test procedure amendments. At 
its next meeting (CAEP/4) in April 1998, the CAEP adopted a similar 16 
percent NO<INF>X</INF> reduction proposal, which the ICAO Council 
approved on February 26, 1999.\16\ The CAEP/4 16 percent NO<INF>X</INF> 
reduction standard applies to new engine designs certified after 
December 31, 2003 (i.e., it applies only to newly certified engines, 
rather than to newly manufactured engines of already certified 
models).<SUP>17 18</SUP>
---------------------------------------------------------------------------

    \15\ ICAO, Foreword of ``Aircraft Engine Emissions,'' 
International Standards and Recommended Practices, Environmental 
Protection, Annex 16, Volume II, Second Edition, July 1993. Copies 
of this document can be obtained from ICAO (http://www.icao.int).
    \16\ International Civil Aviation Organization (ICAO), Aircraft 
Engine Emissions, Annex 16, Volume II, Second Edition, July 1993, 
Amendment 4 effective on July 19, 1999. Copies of this document can 
be obtained from ICAO (http://www.icao.int).
    \17\ These NO<INF>X</INF> standards will be interchangeably be 
referred to as the 1998 CAEP/4 standards and the 1999 ICAO standards 
throughout this Notice.
    \18\ Newly manufactured engines of already certified models are 
those individual engines that are part of an already certified 
engine model, but are built after the effective date of the 
regulations for such engines and have never been in service. This 
does not mean the re-certification or retrofit of existing in-use 
engines.
---------------------------------------------------------------------------

    As discussed earlier, in 1997 EPA amended its regulations to adopt 
the 1981 ICAO NO<INF>X</INF> and CO emission standards, as well as the 
NO<INF>X</INF> emission standards and test procedures revised by ICAO 
in 1993. As discussed above, the U.S. has an obligation under the 
Convention on International Civil Aviation to notify ICAO regarding 
differences between U.S. standards and ICAO standards, and to provide 
notification on the date by which the program requirements will be 
consistent. In response to the recent actions by ICAO and for the 
reasons discussed below, in today's rulemaking EPA is adopting 
standards for newly certified engines that are equivalent to ICAO's 
1999 amendment to the NO<INF>X</INF> emission standard and the test 
procedure changes approved by ICAO in 1997, and EPA is adopting other 
technical amendments to further align EPA and ICAO requirements.

C. EPA's Responsibilities Under the Clean Air Act

    As discussed earlier, section 231 of the CAA directs EPA, from time 
to time, to propose aircraft engine emission standards applicable to 
the emission of any air pollutant from classes of aircraft engines 
which in its judgment causes, or contributes to, air pollution which 
may reasonably be anticipated to endanger public health or welfare. 42 
U.S.C. 7571(a)(2)(A). Section 231(a)(3) provides that after we propose 
standards, the Administrator shall issue such standards ``with such 
modifications as he deems appropriate.'' 42 U.S.C. 7571(a)(3). In 
addition, EPA is required to ensure, in consultation with the Secretary 
of Transportation, that such standards' effective dates provide the 
necessary time to permit the development and application of the 
requisite technology, giving appropriate consideration to compliance 
cost. 42 U.S.C. 7571(b). Also, EPA must consult with the FAA before 
proposing or promulgating emission standards. 42 U.S.C. 
7571(a)(2)(B)(i). (See section VI of today's proposal for further 
discussion of EPA's coordination with FAA and FAA's responsibilities 
under the CAA.)
    In addition, section 233 of the CAA vests authority to implement 
emission standards for aircraft or aircraft engines only in EPA.\19\ 
States are preempted

[[Page 69668]]

from adopting or enforcing any standard respecting aircraft engine 
emissions unless such standard is identical to EPA's standards. 42 
U.S.C. 7573.
---------------------------------------------------------------------------

    \19\ CAA section 233 entitled ``State Standards and Controls'' 
states that ``No State or political subdivision thereof may adopt or 
attempt to enforce any standard respecting emissions of any air 
pollutant from any aircraft or engine thereof unless such standard 
is identical to a standard applicable to such aircraft under this 
part.'' 42 U.S.C. 7573.
---------------------------------------------------------------------------

II. Why Is EPA Taking This Action?

    As mentioned above, section 231(a)(2)(A) of the CAA authorizes the 
Administrator to ``from time to time, issue proposed emission standards 
applicable to emission of any air pollution from any class or classes 
of aircraft or aircraft engines which in his judgment causes, or 
contributes to, air pollution which may reasonably be anticipated to 
endanger public health or welfare.'' 42 U.S.C. 7571(a)(2)(A).
    One of the principal components of aircraft exhaust emissions is 
NO<INF>X</INF>. NO<INF>X</INF> is a precursor to the formation of 
ozone.\20\ Many commercial airports are located in urban areas and many 
of these areas have ambient ozone levels above the National Ambient Air 
Quality Standards (NAAQS) for ozone (i.e., they are in nonattainment 
for ozone). This section discusses the contribution of aircraft engines 
to the national NO<INF>X</INF> emissions inventory and the health and 
welfare impacts of these emissions.
---------------------------------------------------------------------------

    \20\ Ground-level ozone, the main ingredient in smog, is formed 
by complex chemical reactions of volatile organic compounds (VOC) 
and NO<INF>X</INF> in the presence of heat and sunlight. Standards 
that reduce NO<INF>X</INF> emissions will help address ambient ozone 
levels. They can also help reduce particulate matter (PM) levels as 
NO<INF>X</INF> emissions can also be part of the secondary formation 
of PM. See Section II.B below.
---------------------------------------------------------------------------

A. Inventory Contribution

    EPA's estimate of the contribution of aircraft to the national 
NO<INF>X</INF> emission inventory is set out in Table II.A-1. Note that 
this table provides the inventory contributions only for 2001, and 
therefore does not take into account the impacts of our recent mobile 
source emission control programs for highway vehicles and nonroad 
engines and equipment which will go into effect in the coming 
years.\21\ Those new standards are expected to reduce NO<INF>X</INF> 
emissions from highway and nonroad engines by 90 percent or more on a 
per-engine basis. (Nor does the table account for aviation's reduced 
NO<INF>X</INF> emissions due to slower growth and changes in fleet 
composition after 2001.) Nonetheless, as these new programs go into 
effect, the relative size of the contribution of aircraft to national 
NO<INF>X</INF> levels may increase due to the decrease in the 
contribution of those other mobile sources.
---------------------------------------------------------------------------

    \21\ For additional information on the inventory impacts of our 
new rules, see Tables IV-A-1 and IV-A-2 in our Advance Notice of 
Proposed Rulemaking for an additional tier of standards for 
locomotives and marine diesel engines below 30 liters per cylinder 
displacement (69 FR 39276, June 29, 2004).

   Table II.A-1.--Annual NOX Baseline Levels a From EPA's National Air
            Quality and Emissions Trends Report, August 2003
                           [Short tons, 2001]
------------------------------------------------------------------------
 
------------------------------------------------------------------------
                     Category                                NOX
                                                        (Thous. Tons)
---------------------------------------------------
Aircraft b c......................................         81       0.7%
Nonroad...........................................      4,075      32.8%
Highway...........................................      8,249      66.5%
Total Mobile Source...............................     12,405
------------------------------------------------------------------------
 \a\ Source: U.S. EPA, ``Average Annual Emissions, All Criteria
  Pollutants Years Including 1970-2001,'' Updated August 2003. A copy of
  this document can be found in Docket No. OAR-2002-0030.
\b\ These aircraft emissions are a conservative estimate as they reflect
  military operations only at FAA and FAA-contracted facilities and not
  at military bases. See the following memo for further discussion of
  the contribution of military aircraft to total aircraft emissions:
  U.S. EPA, ``Earlier and Current Estimates of Military Aircraft
  Emissions (Updated),'' Memorandum to Docket OAR-2002-0030 from Bryan
  Manning, May 11, 2005.
\c\ There is a new draft version of the national emissions inventories
  (for 2002), and the percentage contribution of the above sources to
  the total mobile source NOX inventory remains essentially the same.

    Aircraft emissions are emitted from a variety of aircraft types 
used for public, private, and military purposes including commercial 
aircraft, air taxis, general aviation, and military aircraft.\22\ 
Commercial aircraft emissions contribute from 74 to 99 percent of the 
NO<INF>X</INF> aircraft emissions in the U.S. The high end of this 
range represents commercial aircraft's fraction of national aircraft 
NO<INF>X</INF> emissions when current estimates for all aircraft types 
(commercial aircraft, air taxis, general aviation, and military 
aircraft) are added together.\23\ The lower end of the range is 
commercial aircraft's contribution of NO<INF>X</INF> aircraft emissions 
in the U.S. when combining earlier \24\ military aircraft estimates 
with current emission estimates for the three other aircraft types (the 
earlier and current estimates were based on different methods or models 
for calculating aircraft emissions in 2001). This range was provided 
since the current estimates of military aircraft emission have 
limitations--i.e., military aircraft estimates are a conservative 
estimate as they reflect military operations only at FAA and FAA-
contracted facilities and not at military bases. For a discussion on 
obtaining improved military aircraft emission estimates, see Section 5 
of the Summary and Analysis of Comments for this rulemaking. (See the 
following memorandum for a further description of the contribution of 
military aircraft to total aircraft emissions: U.S. EPA, ``Earlier and 
Current Estimates of Military Aircraft Emissions (Updated),'' 
Memorandum to Docket OAR-2002-0030 from Bryan Manning (Document No. 
OAR-2002-0030-0214), May 11, 2005.)
---------------------------------------------------------------------------

    \22\ Commercial aircraft include those aircraft used for 
scheduled service transporting passengers, freight, or both. Air 
taxis also fly scheduled service carrying passengers, freight or 
both, and they usually are smaller aircraft than those operated by 
air carriers. Air taxis have played an increasing role in the 
operations of the U.S. aviation system, and by 2015, such operations 
are forecast to represent 54 percent of operations (see Table II.A-2 
and the FAA website http://www.apo.data.faa.gov/main/taf.asp). 
General aviation includes most other aircraft used for recreational 
flying and personal transportation. Aircraft that support business 
travel, usually on an unscheduled basis, are included in the 
category of general aviation. Military aircraft cover a wide range 
of sizes, uses, and operating missions. While they are often similar 
to civil aircraft, they are modeled separately because they often 
operate primarily out of military bases and frequently have 
distinctive flight profiles.
    \23\ U.S. EPA, ``Average Annual Emissions, All Criteria 
Pollutants Years Including 1970-2001,'' Updated August 2003. A copy 
of this document can be found in Docket No. OAR-2002-0030.
    U.S. EPA, ``Documentation for Aircraft, Commercial Marine 
Vessel, Locomotive, and other Nonroad Components of the National 
Emissions Inventory, Volume I--Methodology,'' Prepared for EPA by 
Eastern Research Group, Inc., October 7, 2003. A copy of this 
document can be found in Docket No. OAR-2002-30.
    \24\ The earlier military estimates are based on emission 
inventories from the Final Rule for Control of Emissions from Land-
based Nonroad Diesel Engines, 69 FR 38958, June 29, 2004. Also, see 
the following memorandum for further discussion of the contribution 
of military aircraft to total aircraft emissions and related 
references: U.S. EPA, ``Earlier and Current Estimates of Military 
Aircraft Emissions (Updated),'' Memorandum to Docket OAR-2002-0030 
from Bryan Manning (Document No. OAR-2002-0030-0214), May 11, 2005.
---------------------------------------------------------------------------

    While the current contribution of aircraft to nationwide 
NO<INF>X</INF> is less than one percent, their contribution on a local 
level, especially in areas containing or adjacent to airports can be 
much larger and is also expected to grow. This is illustrated by EPA's 
1999 study that examined NO<INF>X</INF> emissions from aircraft for ten 
cities: Atlanta, Boston-Lawrence-Worcester, Charlotte-Gastonia, 
Chicago-Gary-Lake County, Houston-Galveston-Brazoria, New York-New 
Jersey-Long Island, Philadelphia, Phoenix, Los Angeles Air Basin and

[[Page 69669]]

Washington DC.<SUP>25 26</SUP> Nineteen airport facilities with 
significant commercial jet aircraft activity were identified within 
these selected areas. On average for these ten cities, commercial 
aircraft's contribution is expected to increase from about 2 percent of 
regional total NO<INF>X</INF> emissions in 1990 to about 5 percent in 
2010.
---------------------------------------------------------------------------

    \25\ U.S. EPA, ``Evaluation of Air Pollutant Emissions from 
Subsonic Commercial Jet Aircraft,'' April 1999, EPA420-R-99-013. A 
copy of this document is available at http://www.epa.gov/otaq/aviation.htm. It can also be found in Docket No. OAR-2002-0030, 
Document No. OAR-2002-0030-0002. As indicated in the report, 
comments received from reviewers of this study indicated that 
uncertainty may exist in the national forecasts of growth in 
aircraft activity, on future composition of the aircraft fleet, and 
on the accuracy of a default mixing height. Such uncertainties carry 
over into projections of future emissions, and resolution of 
uncertainties may result in higher or lower ground-level emissions 
estimates from future aircraft.
    \26\ Based on the one-hour ozone standard, nine of the ten 
metropolitan areas are currently not in attainment of NAAQS for one-
hour ozone; the tenth city has attained the one-hour ozone standard 
and is considered an one-hour ozone ``maintenance'' area. Based on 
the 8-hour ozone standard, all ten metropolitan areas are currently 
not in attainment of NAAQS for 8-hour ozone. See section II.B.1 of 
this rule for further discussion on the ozone NAAQs. Also, for more 
detailed information on the 8-hour ozone standard, see the following 
EPA Web sites: http://www.epa.gov/airlinks/ozpminfo.html, http://www.epa.gov/airlinks/airlinks4.html or http://www.epa.gov/ttn/naaqs/ozone/o3imp8hr.
---------------------------------------------------------------------------

    It should be noted that the above study of the impacts of airports 
on regional air quality was conducted before the tragic events of 
September 11, 2001, and the economic downturn in the aircraft 
transportation sector and resulting slowing of emissions growth. A 
report by the Department of Transportation in 2003 indicated that the 
combination of the September 11, 2001 terrorist attacks and cut-backs 
in business travel have had a significant effect on air transportation 
demand.\27\ The FAA expects the demand for air travel to recover and 
then continue a long-term trend of annual growth, though from a lower 
base and a slower rate in the United States.\28\ Thus, there is both a 
short-term decrease in aircraft transportation activity as a result of 
9/11, with negative growth for a few years and associated decreases in 
aircraft emission contributions and lower emissions growth than 
originally anticipated over the time period assessed. This is 
illustrated in Table II.A-2, which compares the results of an earlier, 
pre-9/11 FAA activity forecast to a recent, post-9/11 forecast. As 
operations increase, the inventory impact of these aircraft on national 
and local NO<INF>X</INF> inventories and on ozone levels will also 
increase.
---------------------------------------------------------------------------

    \27\ U.S. Department of Transportation, Office of Inspector 
General, ``Airline Industry Metrics,'' CC-2203-007, January 7, 2003. 
A copy of this document can be found in Docket No. OAR-2002-0030, 
Document No. OAR-2002-0030-0012.
    \28\ U.S. General Accounting Office, ``Aviation and the 
Environment: Strategic Framework Needed to Address Challenges Posed 
by Aircraft Emissions,'' GAO-03-252, February 2003. This document is 
available at http://www.gao.gov/cgi-bin/getrpt?GAO-03-252, and it 
can also be found in the Docket No. OAR-2002-0030, Document No. OAR-
2002-0030-0005.

    Table II.A-2.--FAA Terminal Area Forecast Summary Report of Nationwide Air Carrier and Commuter/Air Taxi
                                              Operations a b c d e
----------------------------------------------------------------------------------------------------------------
                                                                   Air carrier &
                                   Air carrier &  Percent change   commuter/air   Percent change
                                   commuter/air      12/14/00          taxi           6/30/05     Percent change
              Year                     taxi          forecast      operations 6/     forecast     versus earlier
                                  operations 12/   between years       30/05       between years     forecast
                                  14/00 forecast      listed         forecast         listed
                                    (pre-9/11)                      (post-9/11)
----------------------------------------------------------------------------------------------------------------
1999............................      28,860,731  ..............      28,947,500  ..............             0.3
2000............................      29,445,619             2.0      29,714,995             2.7             0.9
2001............................      30,033,967             2.0      29,366,221            -1.2            -2.2
2002\c\.........................      30,663,508             2.1      27,803,970            -5.3            -9.3
2005............................      32,619,194             6.4      29,877,529             7.5            -8.4
2010............................      36,015,595              10      33,118,411              11            -8.0
2015............................      39,549,526              10      36,280,526              10            -8.3
2020............................             N/A  ..............      39,695,796               9  ..............
----------------------------------------------------------------------------------------------------------------
\a\ Source: U.S. FAA, ``APO Terminal Area Forecast Summary Report,'' Aircraft Operations, December 14, 2000; and
  ``APO Terminal Area Forecast Summary Report,'' Aircraft Operations, June 30, 2005. See the following FAA Web
  site: http://www.apo.data.faa.gov/main/taf.asp. A copy of these reports can be found in Docket No. OAR-2002-
  0030.
\b\ Operations means the number of arrivals and departures (see Docket No. OAR-2002-0030, Document No. OAR-2002-
  0030-0258).
\c\ Air carrier operations refers to flights of commercial aircraft with seating capacity of more than 60 seats.
 
\d\ Commuter/air taxi operations refers to aircraft with 60 or fewer seats conducting scheduled commercial
  flights/non-scheduled or for-hire flights.
\e\ The change in operations from 2000 to 2002 was +4.1% for the 12/14/2000 forecast, and it was -6.4% for the 6/
  30/2005 forecast.

    The data in Table II.A-2 show that prior to 9/11 growth in air 
carrier and commuter/air taxi operations was expected to increase by 34 
percent from 2000 to 2015.\29\ The revised growth forecast for this 
period estimates that aircraft activity will now increase only 22 
percent in the period 2000-2015. In fact, the originally anticipated 
operation levels in 2015 are now forecast not to be reached until 
2020.\30\
---------------------------------------------------------------------------

    \29\ U.S. FAA, ``APO Terminal Area Forecast Summary Report,'' 
Aircraft Operations, December 14, 2000. A copy of this document can 
be found in Docket No. OAR-2002-0030.
    \30\ U.S. FAA, ``APO Terminal Area Forecast Summary Report,'' 
Aircraft Operations, June 30, 2005. The flight forecast data is 
based on FAA's Terminal Area Forecast System (TAFS). TAFs is the 
official forecast of aviation activity at FAA facilities. This 
includes FAA-towered airports, federally-contracted towered 
airports, nonfederal towered airports, and many non-towered 
airports. For detailed information on TAFS and the air carrier 
activity forecasts see the following FAA Web site: http://www.apo.data.faa.gov/main/taf.asp. The June 30, 2005 aviation 
forecasts contained in TAFS for Fiscal Years 2002-2020 included the 
impact of the terrorists' attacks of September 11, 2001 and the 
recent economic downturn. Currently, the aviation industry is 
undergoing significant structural and economic changes. These 
changes may necessitate revisions to forecasts for a number of large 
hub airports prior to the update of the entire TAF next year. A copy 
of the June 30, 2005 forecast summary report can also be found in 
Docket No. OAR-2002-0030.
---------------------------------------------------------------------------

    Aircraft emissions are a large portion of total emissions 
associated with airports. Air pollutants resulting from airport 
operations are emitted from several types of sources including aircraft 
main engines and auxiliary power units (APUs); ground support equipment 
(GSE), which includes vehicles such as aircraft tugs, baggage tugs, 
fuel trucks, maintenance vehicles, and other miscellaneous vehicles 
used to support aircraft operations; and ground access vehicles (GAV), 
which include vehicles used by passengers, employees, freight 
operators, and other persons to enter and leave an airport.

[[Page 69670]]

EPA estimates that aircraft engines comprise approximately 45 percent 
of total air pollutant emissions from airport operations. GAV account 
for another 45 percent and APUs and GSE combined make up the remaining 
10 percent.\31 32\ Since EPA has established stringent emission 
standards for GAVs and other highway and nonroad vehicles used at 
airports, overall emissions from these vehicles will continue to 
decline for many years. This means that aircraft will contribute an 
increasing portion of total emissions associated with airport 
operations.
---------------------------------------------------------------------------

    \31\ The California FIP, signed by the Administrator 2/14/95, is 
located in EPA Air Docket A-94-09, item number V-A-1. The FIP was 
vacated by an act of Congress before it became effective.
    \32\ For comparison, the 1997 EPA Draft Final Report entitled, 
``Analysis of Techniques to Reduce Air Emission at Airports'' 
(prepared by Energy and Environmental Analysis, Inc), estimated that 
for the four airports studied (which are large air traffic hubs) on 
average aircraft comprise approximately 35 percent of NO<INF>X</INF> 
emissions from airport operations; GAV account for another 35 
percent, and APUs and GSE contribute about 15 percent each for the 
remaining 30 percent. For NO<INF>X</INF> and VOC together, aircraft 
contribute about 35 percent; GAV account for another 40 percent, and 
APUs and GSE combined make up the remaining 25 percent. This 
document can be found in Docket No. OAR-2002-0030, Document No. OAR-
2002-0030-0071.
---------------------------------------------------------------------------

B. Health and Welfare Effects

    NO<INF>X</INF> emissions from commercial aircraft and other mobile 
and stationary sources contribute to the formation of ozone. In 
addition, NO<INF>X</INF> emissions at low altitude also react in the 
atmosphere to form secondary particulate matter (PM<INF>2.5</INF>), 
particularly ammonium nitrate, and contribute to regional haze.\33\ The 
NO<INF>X</INF> standards adopted in this rule will help reduce ambient 
ozone and potentially secondary PM levels and thus will help areas with 
airports achieve and/or maintain compliance with the NAAQS for ozone 
and potentially PM.\34\ In the following section we discuss the adverse 
health and welfare effects associated with NO<INF>X</INF> emissions.
---------------------------------------------------------------------------

    \33\ As described later in section II.B.2, fine particles refer 
to those particles with an aerodynamic diameter less than or equal 
to a nominal 2.5 micrometers (also known as PM<INF>2.5</INF>).
    \34\ The NO<INF>X</INF> standards being set today will also help 
reduce levels of nitrogen dioxide (NO<INF>2</INF>), for which NAAQS 
have been established. Currently, every area in the United States 
has been designated to be in attainment with the NO<INF>2</INF> 
NAAQS.
---------------------------------------------------------------------------

1. Ozone
a. What are the health effects of ozone pollution?
    NO<INF>X</INF> is a precursor in the photochemical reaction which 
forms tropospheric ozone. Ground-level ozone, the main ingredient in 
smog, is formed by complex chemical reactions of VOCs and 
NO<INF>X</INF> in the presence of heat and sunlight. The health effects 
of ozone pollution are described in detail in EPA's Air Quality 
Criteria Document for Ozone and Other Photochemical Oxidants and are 
also described in the Final Regulatory Analysis for our recent Clean 
Air Nonroad Diesel rule.\35\ The following is a summary of those 
effects.
---------------------------------------------------------------------------

    \35\ U.S. EPA (1996). Air Quality Criteria for Ozone and Related 
Photochemical Oxidants, EPA/600/P-93/004aF. This document can be 
found in Docket No. OAR-2002-0030. Document Nos. OAR-2002-0030-0165 
through OAR-2002-0030-0194. (U.S. EPA (2005), Air Quality Criteria 
for Ozone and Related Photochemical Oxidants (First External Review 
Draft), EPA/600/R-05/004aA-cA. This document can be found in Docket 
No. OAR-2002-0030, Document Nos. OAR-2002-0030-0202, -0210, and -
0211.) U.S. EPA (2004). Final Regulatory Assessment: Control of 
Emissions from Nonroad Diesel Engines, EPA420-R-04-007. This 
document can be found in Docket No. OAR-2002-0030, Document No. OAR-
2002-0030-0128.
---------------------------------------------------------------------------

    Ozone can irritate the respiratory system, causing coughing, throat 
irritation, and/or uncomfortable sensation in the chest. In addition, 
ozone can reduce lung function and make it more difficult to breathe 
deeply, and breathing may become more rapid and shallow than normal, 
thereby limiting a person's normal activity. Ozone also can aggravate 
asthma, leading to more asthma attacks that require a doctor's 
attention and/or the use of additional medication. In addition, ozone 
can inflame and damage the lining of the lungs, which may lead to 
permanent changes in lung tissue, irreversible reductions in lung 
function, and a lower quality of life if the inflammation occurs 
repeatedly over a long time period. People who are of particular 
concern with respect to ozone exposures include children and adults who 
are active outdoors. Those people particularly susceptible to ozone 
effects are people with respiratory disease, such as asthma, people 
with unusual sensitivity to ozone, and children. Beyond its human 
health effects, ozone has been shown to injure plants, which has the 
effect of reducing crop yields and reducing productivity in forest 
ecosystems.\36 37\
---------------------------------------------------------------------------

    \36\ U.S. EPA (1996). Review of National Ambient Air Quality 
Standards for Ozone, Assessment of Scientific and Technical 
Information, OAQPS Staff Paper, EPA-452/R-96-007. Docket No. A-99-
06. Document No. II-A-22.
    \37\ U.S. EPA (1996). Air Quality Criteria for Ozone and Related 
Photochemical Oxidants, EPA/600/P-93/004aF. This document can be 
found in Docket No. OAR-2002-0030, Document Nos. OAR-2002-0030-0165 
through OAR-2002-0030-0194. (U.S. EPA (2005). Air Quality Criteria 
for Ozone and Related Photochemical Oxidants (First External Review 
Draft), EPA/600/R-05/004aA-cA. This document can be accessed 
electronically at: http://www.epa.gov/ttn/naaqs/standards/ozone/s_o3_cr_cd.html. This document can also be found in Docket No. OAR-
2002-0030, Doc. Nos. OAR-2002-0030-0202, -0210, and -0211.)
---------------------------------------------------------------------------

    New research suggests additional serious health effects beyond 
those that were known when the ozone NAAQS was revised in 1997. Between 
1997 and a 2002 literature review, over 1,700 new health and welfare 
studies relating to ozone have been published in peer-reviewed 
journals.\38\ Many of these studies investigate the impact of ozone 
exposure on such health effects as changes in lung structure and 
biochemistry, inflammation of the lungs, exacerbation and causation of 
asthma, respiratory illness-related school absence, hospital and 
emergency room visits for asthma and other respiratory causes, and 
premature mortality. EPA is currently evaluating these and other 
studies as part of the ongoing review of the air quality criteria and 
NAAQS for ozone. A revised Air Quality Criteria Document for Ozone and 
Other Photochemical Oxidants will be prepared in consultation with 
EPA's Clean Air Science Advisory Committee (CASAC).\39\ Key new health 
information falls into four general areas: development of new-onset 
asthma, hospital admissions for young children, school absence rate, 
and premature mortality. In all, the new studies that have become 
available since the 8-hour ozone standard was adopted in 1997 continue 
to demonstrate the harmful effects of ozone on public health and the 
need for areas with high ozone levels to attain and maintain the NAAQS.
---------------------------------------------------------------------------

    \38\ New Ozone Health and Environmental Effects References, 
Published Since Completion of the Previous Ozone AQCD, National 
Center for Environmental Assessment, Office of Research and 
Development, U.S. Environmental Protection Agency, Research Triangle 
Park, NC 27711 (7/2002). This document can be found in Docket No. 
OAR-2002-0030, Document No. OAR-2002-0030-0131.
    \39\ U.S. EPA (2005), Air Quality Criteria for Ozone and Related 
Photochemical Oxidants (First External Review Draft), Volume I 
Document No. EPA/600/R-05/004aA, Volume II Document No. EPA/600/R-
05/004bA, Volume III Document No. EPA/600/R-05/004cA. This document 
can be found in Docket No. OAR-2002-0030, Document Nos. OAR-2002-
0030-0202, -0210, and -0211.
---------------------------------------------------------------------------

b. What are the current and projected 8-hour ozone levels?
    There is currently one ozone NAAQS, an 8-hour standard. The 8-hour 
ozone standard is met when the fourth highest daily maximum 8-hour 
average ozone concentration measured over a 3-year period is less than 
or equal to 0.084 parts per million (ppm). The former 1-hour ozone 
standard was revoked in June 2005.\40\
---------------------------------------------------------------------------

    \40\ U.S. EPA, National Ambient Air Quality Standards for Ozone; 
Final Rule. 62 FR 38855 (July 18, 1997). U.S. EPA, ``Final Rule to 
Implement the 8-Hour Ozone National Ambient Air Quality Standard--
Phase 1,'' Final Rule, 69 FR 23951 (April 30, 2004).

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

[[Page 69671]]

    On June 15, 2004, the 8-hour ozone nonattainment designations 
became effective.\41\ Nationwide, there are approximately 159 million 
people living in 126 areas that are designated as not attaining the 8-
hour ozone NAAQS based upon the monitored data from 2001-2003 and other 
factors. The CAA defines a nonattainment area as an area that is 
violating an ambient standard or is contributing to a nearby area that 
is violating the standard. All or part of 474 counties are designated 
as nonattainment for the 8-hour ozone NAAQS. These counties are spread 
over wide geographic areas, including most of the nation's major 
population centers, which include much of the eastern half of the U.S. 
and large areas of California.\42\
---------------------------------------------------------------------------

    \41\ U.S. EPA, ``Air Quality Designations and Classifications 
for the 8-hour Ozone National Ambient Air Quality Standards; Early 
Action Compact Areas With Deferred Effective Dates,'' Final Rule, 69 
FR 23858 (April 30, 2004).
    \42\ A map that shows the current 8-hour ozone and 
PM<INF>2.5</INF> nonattainment areas, federal Class I areas, and a 
list of affected counties can be found in Docket No. OAR-2002-0030, 
Document No. OAR-2002-0030-0209.
---------------------------------------------------------------------------

    From air quality modeling performed for the recent Clean Air 
Interstate Rule (CAIR),\43\ we anticipate that without emission 
reductions beyond those already required under promulgated regulation 
and approved State Implementation Plans (SIPs), ozone nonattainment 
will likely persist into the future. With reductions from programs 
already in place, including the CAIR, the number of counties in the 
eastern U.S. violating the ozone 8-hour standard is expected to 
decrease in 2015 to 16 counties where 12 million people are projected 
to live.
---------------------------------------------------------------------------

    \43\ U.S. EPA, ``Rule To Reduce Interstate Transport of Fine 
Particulate Matter and Ozone (Clean Air Interstate Rule); Revisions 
to Acid Rain Program; Revisions to the NO<INF>X</INF> SIP Call,'' 
Final Rule, 70 FR 25162, May 12, 2005.
---------------------------------------------------------------------------

    On June 2, 2003 (68 FR 32802), EPA issued a proposal for the 
implementation process to bring the nation's air into attainment with 
the 8-hour ozone NAAQS, including proposed requirements that States 
submit SIPs that address how areas will attain the 8-hour ozone 
standard.\44\ The second phase (Phase II) of this proposed 
implementation process for the 8-hour ozone NAAQS will be finalized in 
the next few months, and it will describe the SIP submittal date 
requirements. (Phase I of the proposed implementation process was 
finalized on April 30, 2004 (69 FR 23951), but it did not include these 
SIP submittal date requirements.) \45\
---------------------------------------------------------------------------

    \44\ U.S. EPA, ``Proposed Rule to Implement the 8-hour Ozone 
National Ambient Air Quality Standard,'' Proposed Rule, 68 FR 32802 
(June 2, 2003).
    \45\ U.S. EPA, ``Final Rule to Implement the 8-Hour Ozone 
National Ambient Air Quality Standard--Phase 1,'' Final Rule, 69 FR 
23951 (April 30, 2004).
---------------------------------------------------------------------------

    The Act (Title I, Part D) contains two sets of requirements for 
State plans implementing the national ozone air quality standards in 
nonattainment areas. Subpart 1 contains general requirements for SIPs 
for nonattainment areas for any pollutant, including ozone, governed by 
a NAAQS. Subpart 2 provides more specific requirements for ozone 
nonattainment SIPs. Under subpart 1, a state must demonstrate that its 
nonattainment areas will attain the ozone 8-hour standard as 
expeditiously as practicable, but no later than five years from the 
date that the area was designated nonattainment. However, based on the 
severity of the air quality problem and the availability and 
feasibility of control measures, the Administrator may extend the 
attainment date ``for a period of no greater than 10 years from the 
date of designation as nonattainment.'' Based on these provisions, we 
expect that most or all areas covered under subpart 1 will attain the 
8-hour ozone standard in the 2007 to 2014 time frame. For areas covered 
under subpart 2, the maximum attainment dates provided under the Act 
range from 3 to 20 years after designation, depending on an area's 
classification. Thus, we anticipate that areas covered by subpart 2 
will attain the 8-hour ozone standard in the 2007 to 2024 time period.
    Since the emission reductions expected from the standards we are 
adopting in this rule will occur during the time period when areas will 
need to attain the standard under either option, projected reductions 
in aircraft engine emissions will assist States in their efforts to 
attain and maintain the 8-hour ozone NAAQS.
2. Particulate Matter
a. What is particulate matter?
    Particulate matter represents a broad class of chemically and 
physically diverse substances. It can be principally characterized as 
discrete particles that exist in the condensed (liquid or solid) phase 
spanning several orders of magnitude in size. PM<INF>10</INF> refers to 
particles with an aerodynamic diameter less than or equal to a nominal 
10 micrometers. Fine particles refer to those particles with an 
aerodynamic diameter less than or equal to a nominal 2.5 micrometers 
(also known as PM<INF>2.5</INF>). The emission sources, formation 
processes, chemical composition, atmospheric residence times, transport 
distances and other parameters of fine and coarse particles are 
distinct. This discussion focuses on fine PM since the NO<INF>X</INF> 
emitted by aircraft engines can react in the atmosphere to form fine PM 
as discussed below.
    Fine particles are directly emitted from combustion sources and are 
formed secondarily from gaseous precursors such as oxides of nitrogen 
(NO<INF>X</INF>). Fine particles are generally composed of sulfate, 
nitrate, chloride, ammonium compounds, organic carbon, elemental 
carbon, and metals. Aircraft engines emit NO<INF>X</INF> which reacts 
in the atmosphere to form secondary PM<INF>2.5</INF> (namely ammonium 
nitrate). Combustion of coal, oil, diesel, gasoline, and wood, as well 
as high temperature process sources such as smelters and steel mills, 
produce emissions that contribute to fine particle formation. Fine 
particles can remain in the atmosphere for days to weeks and travel 
through the atmosphere hundreds to thousands of kilometers. Thus 
emissions from aircraft, as well as those from other sources, could 
affect nonattainment areas far from their source.
    The relative contribution of various chemical components to 
PM<INF>2.5</INF> varies by region of the country. Data on 
PM<INF>2.5</INF> composition are available from the EPA Speciation 
Trends Network in 2001 and the Interagency Monitoring of PROtected 
Visual Environments (IMPROVE) network in 1999 covering both urban and 
rural areas in numerous regions of the U.S. These data show that 
nitrates formed from NO<INF>X</INF> play a major role in the western 
U.S., especially in the California area where it is responsible for 
about a quarter of the ambient PM<INF>2.5</INF> concentrations.\46\ 
(However, the majority of NO<INF>X</INF> involved in this process does 
not come from aircraft.)
---------------------------------------------------------------------------

    \46\ See the Regulatory Impact Analysis: ``Final Regulatory 
Analysis: Control of Emissions from Nonroad Diesel Engines,'' 
EPA420-R-04-007, May 2004. This document is available at http://www.epa.gov/nonroad/ and in Docket No. OAR-2002-0030, Document No. 
OAR-2002-0030-0128.
---------------------------------------------------------------------------

b. What are the health effects of PM<INF>2.5</INF>?
    Scientific studies show ambient PM is associated with a series of 
adverse health effects. These health effects are discussed in detail in 
the recently released EPA Criteria Document for PM.\47\ They are also 
described in the Final Regulatory Analysis for our recent

[[Page 69672]]

Clean Air Nonroad Diesel rule.\48\ The following is a summary of those 
effects.
---------------------------------------------------------------------------

    \47\ U.S. EPA, Air Quality Criteria for Particulate Matter (OCT 
2004), Volume I Document No. EPA600/P-99/002aF and Volume II 
Document No. EPA600/P-99/002bF. This document is available in Docket 
No. OAR-2002-0030, Document No. OAR-2002-0030-0129 and OAR-2002-
0030-0130.
    \48\ U.S. EPA (2004). Final Regulatory Assessment: Control of 
Emissions from Nonroad Diesel Engines, EPA420-R-04-007. This 
document can be found in Docket No. OAR-2002-0030, Document No. OAR-
2002-0030-0128.
---------------------------------------------------------------------------

    The health effects associated with short-term variation in ambient 
particulate matter (PM) have been indicated by epidemiologic studies 
showing associations between exposure and increased hospital admissions 
for ischemic heart disease, heart failure, respiratory disease, 
including chronic obstructive pulmonary disease (COPD) and pneumonia. 
Short-term elevations in ambient PM have also been associated with 
increased cough, lower respiratory symptoms, and decrements in lung 
function. Additional studies have associated changes in heart rate and/
or heart rhythm in addition to changes in blood characteristics with 
exposure to ambient PM. Short-term variations in ambient PM have also 
been associated with increases in total and cardiorespiratory 
mortality. Studies examining populations exposed to different levels of 
air pollution over a number of years, including the Harvard Six Cities 
Study and the American Cancer Society Study, suggest an association 
between exposure to ambient PM<INF>2.5</INF> and premature 
mortality.<SUP>49</SUP> <SUP>50</SUP> Additionally, one long-term study 
provides evidence for premature mortality specifically associated with 
PM generated by mobile sources.\51\ Two studies further analyzing the 
Harvard Six Cities Study's air quality data have also established a 
specific influence of mobile source-related PM<INF>2.5</INF> on daily 
mortality \52\ and a concentration-response function for mobile source-
associated PM<INF>2.5</INF> and daily mortality.\53\
---------------------------------------------------------------------------

    \49\ Dockery, DW; Pope, CA, III; Xu, X; et al. (1993) An 
association between air pollution and mortality in six U.S. cities. 
N Engl J Med 329:1753-1759.
    \50\ Pope, CA, III; Thun, MJ; Namboordiri, MM; et al. (1995) 
Particulate air pollution as a predictor of mortality in a 
prospective study of U.S. adults. Am J Respir Crit Care Med 151:669-
674.
    \51\ Hoek, G; Brunekreef, B; Goldbohm, S; et al. (2002) 
Association between mortality and indicators of traffic-related air 
pollution in the Netherlands: a cohort study. Lancet 360:1203-1209.
    \52\ Laden F; Neas LM; Dockery DW; et al. (2000) Association of 
fine particulate matter from different sources with daily mortality 
in six U.S. cities. Environ Health Perspect 108(10):941-947.
    \53\ Schwartz J; Laden F; Zanobetti A. (2002) The concentration-
response relation between PM(<INF>2.5</INF>) and daily deaths. 
Environ Health Perspect 110(10): 1025-1029.
---------------------------------------------------------------------------

c. What are current and projected levels of PM?
    The NAAQS for PM<INF>2.5</INF> were established by EPA in 1997 (62 
FR 38651, July 18, 1997). The short-term (24-hour) standard is set at a 
level of 65 [mu]g/m<SUP>3</SUP> based on the 98th percentile 
concentration averaged over three years. The long-term standard 
specifies an expected annual arithmetic mean not to exceed 15 ug/
m<SUP>3</SUP> averaged over three years.
    Approximately 88 million people live in 208 full and partial 
counties and 39 areas which EPA has designated nonattainment for the 
PM<INF>2.5</INF> NAAQS.\54\ In addition, tens of millions of people 
live in areas where there is a significant future risk of failing to 
maintain or achieve the PM<INF>2.5</INF> NAAQS.
---------------------------------------------------------------------------

    \54\ A map that shows the current 8-hour ozone and 
PM<INF>2.5</INF> nonattainment areas, federal Class I areas, and a 
list of affected counties can be found in Docket No. OAR-2002-0030, 
Document No. OAR-2002-0030-0209. The final PM<INF>2.5</INF> 
designations were effective on April 5, 2005. (U.S. EPA, ``Air 
Quality Designations and Classifications for the Fine Particles 
(PM<INF>2.5</INF>) National Ambient Air Quality Standards,'' Final 
Rule, January 5, 2005 (70 FR 944); ``Air Quality Designations for 
the Fine Particles (PM<INF>2.5</INF>) National Ambient Air Quality 
Standards,'' Supplemental Notice, April 5, 2005, located at http://www.epa.gov/pmdesignations/ pmdesignations/.)
---------------------------------------------------------------------------

    This is illustrated by the air quality modeling performed recently 
in connection with our CAIR rule, which suggests that elevated 
PM<INF>2.5</INF> levels are likely to continue to exist in the future 
in many areas in the absence of additional emission controls.\55\ For 
example in the eastern U.S. in 2015, based on emission controls 
currently adopted, we project that 16 million people will live in 18 
counties with average PM<INF>2.5</INF> levels above 15 [mu]/
m<SUP>3</SUP>.
---------------------------------------------------------------------------

    \55\ U.S. EPA, ``Rule To Reduce Interstate Transport of Fine 
Particulate Matter and Ozone (Clean Air Interstate Rule); Revisions 
to Acid Rain Program; Revisions to the NO<INF>X</INF> SIP Call,'' 
Final Rule, 70 FR 25162, May 12, 2005.
---------------------------------------------------------------------------

    While the final implementation process for bringing the nation's 
air into attainment with the PM<INF>2.5</INF> NAAQS is still being 
completed in a separate rulemaking action, the basic framework is well 
defined by the statute. EPA designated PM<INF>2.5</INF> nonattainment 
areas on April 5, 2005. Following designation, section 172(b) of the 
Clean Air Act allows states up to three years to submit a revision to 
their state implementation plan (SIP) that provides for the attainment 
of the PM<INF>2.5</INF> standard. Based on this provision, states could 
submit these SIPs as late as the end of 2007. Section 172(a)(2) of the 
Clean Air Act requires that these SIP revisions demonstrate that the 
nonattainment areas will attain the PM<INF>2.5</INF> standard as 
expeditiously as practicable but no later than five years from the date 
that the area was designated nonattainment. However, based on the 
severity of the air quality problem and the availability and 
feasibility of control measures, the Administrator may extend the 
attainment date ``for a period of no greater than 10 years from the 
date of designation as nonattainment.'' Therefore, based on this 
information, we expect that most or all are as will need to attain the 
PM<INF>2.5</INF> NAAQS in the 2009 to 2014 time frame, and then be 
required to maintain the NAAQS thereafter.
    Potentially, today's aircraft NO<INF>X</INF> standards may 
contribute to attainment and maintenance of the existing PM NAAQS since 
NO<INF>X</INF> contributes to the secondary formation of 
PM<INF>2.5</INF>.

C. Other Environmental Effects

    This section presents information on four categories of public 
welfare and environmental impacts related to NO<INF>X</INF> and fine PM 
emissions: Acid deposition, eutrophication of water bodies, plant 
damage from ozone, and visibility impairment. These environmental 
effects are described in detail in the Final Regulatory Assessment for 
our recent Clean Air Nonroad Diesel rule.\56\
---------------------------------------------------------------------------

    \56\ U.S. EPA (2004). Final Regulatory Assessment: Control of 
Pollution from Nonroad Diesel Engines, EPA420-R-04-007. This 
document can be found in Docket No. OAR-2002-0030, Document No. OAR-
2002-0030-0128.
---------------------------------------------------------------------------

1. Acid Deposition
    Acid deposition, or acid rain as it is commonly known, occurs when 
NO<INF>X</INF> and SO<INF>2</INF> react in the atmosphere with water, 
oxygen, and oxidants to form various acidic compounds that later fall 
to earth in the form of precipitation or dry deposition of acidic 
particles.\57\ Acid rain contributes to damage of trees at high 
elevations and in extreme cases may cause lakes and streams to become 
so acidic that they cannot support aquatic life. In addition, acid 
deposition accelerates the decay of building materials and paints, 
including irreplaceable buildings, statues, and sculptures that are 
part of our nation's cultural heritage. To reduce damage to automotive 
paint caused by acid rain and acidic dry deposition, some manufacturers 
use acid-resistant paints, at an average cost of $5 per vehicle for a 
total of $80-85 million per year when applied to all new cars and 
trucks sold in the U.S. each year.
---------------------------------------------------------------------------

    \57\ Much of the information in this subsection was excerpted 
from the EPA document, Human Health Benefits from Sulfate Reduction, 
written under Title IV of the 1990 Clean Air Act Amendments, U.S. 
EPA, Office of Air and Radiation, Acid Rain Division, Washington, DC 
20460, November 1995. A copy of this document is available in Docket 
No. OAR 2002-0030, Document No. OAR-2002-0030-0028.
---------------------------------------------------------------------------

    The NO<INF>X</INF> reductions from today's action will help reduce 
acid rain and acid deposition, thereby helping to reduce acidity levels 
in lakes and

[[Page 69673]]

streams throughout the country and helping to accelerate the recovery 
of acidified lakes and streams and the revival of ecosystems adversely 
affected by acid deposition. Reduced acid deposition levels will also 
help reduce stress on forests, thereby accelerating reforestation 
efforts and improving timber production. Deterioration of our historic 
buildings and monuments, and of buildings, vehicles, and other 
structures exposed to acid rain and dry acid deposition will be 
reduced, and the costs borne to prevent acid-related damage may also 
decline.
2. Eutrophication and Nitrification
    In recent decades, human activities have greatly accelerated 
nutrient impacts, such as nitrogen and phosphorus, causing excessive 
growth of algae and leading to degraded water quality and associated 
impairment of fresh water and estuarine resources for human uses.\58\ 
Eutrophication is the accelerated production of organic matter, 
particularly algae, in a water body. This increased growth can cause 
numerous adverse ecological effects and economic impacts, including 
nuisance algal blooms, dieback of underwater plants due to reduced 
light penetration, and toxic plankton blooms. Algal and plankton blooms 
can also reduce the level of dissolved oxygen, which can also adversely 
affect fish and shellfish populations.
---------------------------------------------------------------------------

    \58\ Deposition of Air Pollutants to the Great Waters, Third 
Report to Congress, June 2000, EPA-453/R-00-005. This document can 
be found in Docket No. OAR-2002-0030, Document No. OAR-2002-0030-
0025. It is also available at http://www.epa.gov/oar/oaqps/gr8water/3rdrpt/obtain.html.
---------------------------------------------------------------------------

    Deposition of nitrogen from aircraft engines contributes to 
elevated nitrogen levels in waterbodies. The NO<INF>X</INF> reductions 
from today's promulgated standards will help reduce the airborne 
nitrogen deposition that contributes to eutrophication of watersheds, 
particularly in aquatic systems where atmospheric deposition of 
nitrogen represents a significant portion of total nitrogen loadings.
3. Plant Damage From Ozone
    Ground-level ozone can also cause adverse welfare or environmental 
effects.\59\ Specifically, ozone enters the leaves of plants where it 
interferes with cellular metabolic processes. This interference can be 
manifest either as visible foliar injury from cell injury or death, 
and/or as decreased plant growth and yield due to a reduced ability to 
produce food. With fewer resources, the plant reallocates existing 
resources away from root storage, growth and reproduction toward leaf 
repair and maintenance. Plants that are stressed in these ways become 
more susceptible to disease, insect attack, harsh weather and other 
environmental stresses. Because not all plants are equally sensitive to 
ozone, ozone pollution can also exert a selective pressure that leads 
to changes in plant community composition.
---------------------------------------------------------------------------

    \59\ U.S. EPA (1996). Air Quality Criteria for Ozone and Related 
Photochemical Oxidants, EPA/600/P-93/004aF. This document can be 
found in Docket No. OAR-2002-0030. Document Nos. OAR-2002-0030-0165 
through OAR-2002-0030-0194. (U.S. EPA (2005), Air Quality Criteria 
for Ozone and Related Photochemical Oxidants (First External Review 
Draft), EPA/600/R-05/004aA--cA. This document can be found in Docket 
No. OAR-2002-0030, Document Nos. OAR-2002-0030-0202, -0210, and -
0211.)
---------------------------------------------------------------------------

    As discussed earlier, aircraft engine emissions of NO<INF>X</INF> 
contribute to ozone. The final standards will aid in the reduction of 
ozone and, therefore, help reduce crop damage and stress from ozone on 
vegetation.
4. Visibility
    Visibility can be defined as the degree to which the atmosphere is 
transparent to visible light.\60\ Fine particles with significant 
light-extinction efficiencies include organic matter, sulfates, 
nitrates, elemental carbon (soot), and soil.
---------------------------------------------------------------------------

    \60\ National Research Council, 1993. Protecting Visibility in 
National Parks and Wilderness Areas. National Academy of Sciences 
Committee on Haze in National Parks and Wilderness Areas. National 
Academy Press, Washington, DC. This book can be viewed on the 
National Academy Press Web site at http://www.nap.edu/books/0309048443/html/. See also U.S. EPA Air Quality Criteria Document 
for Particulate Matter (2004). This document is available in Docket 
No. OAR-2002-0030, Document No. OAR-2002-0030-0129 and OAR-2002-
0030-0130. See also Review of the National Ambient Air Quality 
Standards for Particulate Matter: Policy Assessment of Scientific 
and Technical Information, 2nd Draft. This document can be found in 
Docket No. OAR-2002-0030, Document Nos. OAR-2002-0030-0198 through--
0201. It is also available electronically at http://www.epa.gov/ttn/naaqs/standards/pm/data/pm_staff_paper_2nddraft.pdf.
---------------------------------------------------------------------------

    Visibility is important because it directly affects people's 
enjoyment of daily activities in all parts of the country. Individuals 
value good visibility for the well-being it provides them directly, 
both in where they live and work, and in places where they enjoy 
recreational opportunities. Visibility is also highly valued in 
significant natural areas such as national parks and wilderness areas, 
because of the special emphasis given to protecting these lands now and 
for future generations.
    As discussed previously, aircraft engine emissions of 
NO<INF>X</INF> are precursors to PM<INF>2.5</INF>. In 1997, EPA 
established the secondary (welfare-based) PM<INF>2.5</INF> NAAQS as 
equal to the primary (health-based) NAAQS of 15 ug/m<SUP>3</SUP> (based 
on a 3-year average of the annual mean) and 65 ug/m<SUP>3</SUP> (based 
on a 3-year average of the 98th percentile of the 24-hour average 
value) (62 FR 38669, July 18, 1997). EPA concluded that 
PM<INF>2.5</INF> causes adverse effects on visibility in various 
locations, depending on PM concentrations and factors such as chemical 
composition and average relative humidity. In 1997, EPA demonstrated 
that visibility impairment is an important effect on public welfare and 
that unacceptable visibility impairment is experienced throughout the 
U.S., in multi-state regions, urban areas, and remote federal Class I 
areas.\61\
---------------------------------------------------------------------------

    \61\ A map that shows the current 8-hour ozone and 
PM<INF>2.5</INF> nonattainment areas, federal Class I areas, and a 
list of affected counties can be found in Docket No. OAR-2002-0030, 
Document No. OAR-2002-0030-0209.
---------------------------------------------------------------------------

    Furthermore, in setting the PM<INF>2.5</INF> NAAQS, EPA 
acknowledged that levels of fine particles below the NAAQS may also 
contribute to unacceptable visibility impairment and regional haze 
problems in some areas, and section 169 of the Act provides additional 
authorities to remedy existing impairment and prevent future impairment 
in the 156 national parks, forests and wilderness areas labeled as 
mandatory Federal Class I areas (62 FR 38680-81, July 18, 1997).
    Taken together with other programs, potential reductions from this 
final rule may help to improve visibility across the nation, including 
mandatory Federal Class I areas.

III. Aircraft Engine Standards

    Under the authority of section 231 of the CAA, EPA today adopts 
standards equivalent to ICAO's February 1999 NO<INF>X</INF> emission 
standards (these NO<INF>X</INF> standards were adopted at CAEP/4 in 
1998 and approved by the ICAO Council in 1999) and March 1997 test 
procedure amendments. Today's emission standards and test procedure 
amendments apply to commercial aircraft engines, and these standards do 
not apply to aircraft engines used only for general aviation or 
military applications.\62\ (General aviation and military aircraft can 
use commercial aircraft engines subject to these standards--e.g., small 
regional jet engines are also utilized in executive general aviation 
aircraft and larger commercial aircraft engines may also be used in 
military transport aircraft). The

[[Page 69674]]

commercial aircraft engines subject to today's NO<INF>X</INF> standards 
are those gas turbine engines that are newly certified (and newly 
designed) after the effective dates of the regulations. (Newly 
manufactured engines of already certified models--i.e., those 
individual engines that are part of an already certified engine model, 
but are built after the effective date of the regulations for such 
engines and have never been in service--will not have to meet these 
standards).\63\ The NO<INF>X</INF> emission standards and their 
effective dates are described below in this section, and the test 
procedure amendments are discussed later in section IV.
---------------------------------------------------------------------------

    \62\ In the proposal, we stated that no general aviation or 
military engines are covered by the proposal; however, this 
statement may need some clarification in today's final rulemaking. 
See the Section 5.2 of the Summary and Analysis of Comments of this 
rulemaking for further discussion of general aviation and military 
aircraft.
    \63\ Applying standards to newly manufactured engines of already 
certified models does not mean the re-certification or retrofit of 
existing in-use engines. Instead such a provision would require the 
ongoing production of engines that have already been certified to 
meet the new standards. However, we are not adopting this provision 
in today's rulemaking
---------------------------------------------------------------------------

A. What Are The NO<INF>X</INF> Standards For Newly Certified Engines?

    As discussed earlier in sections I and II of today's notice, 
section 231(a)(2)(A) of the CAA authorizes EPA to establish emission 
standards for aircraft engine emissions `` * * * which in his judgment 
causes, or contributes to, air pollution which may reasonably be 
anticipated to endanger public health or welfare.'' The Administrator 
may revise such standards from ``time to time.'' 42 U.S.C. 7571(a)(2). 
CAA section 231(b) requires that any emission standards provide 
sufficient lead time ``to permit the development and application of the 
requisite technology, giving appropriate consideration to the cost of 
compliance within such period.'' 42 U.S.C. 7571(b).
    Today's rule adopts near-term standards that will go into effect 
December 19, 2005 to ensure future engines do not jeopardize recent or 
past technology gains. These standards are equivalent to the CAEP/4 
NO<INF>X</INF> international consensus emissions standards for aircraft 
engines adopted by ICAO's CAEP in 1998.\64\ This final rule to 
promulgate aircraft engine NO<INF>X</INF> standards equivalent to CAEP/
4 standards is consistent with U.S. obligations under ICAO. By issuing 
standards that meet or exceed ICAO CAEP/4 standards, we satisfy these 
obligations. As indicated earlier in section I of today's rule, the 
implementation date, December 31, 2003, has already occurred for the 
CAEP/4 standards, and we need to promulgate the standards in accordance 
with U.S. obligations under ICAO. At the same time, EPA anticipates 
establishing more stringent NO<INF>X</INF> standards in the future. In 
February 2004, CAEP/6 (sixth meeting of CAEP) agreed to establish more 
stringent international consensus emission standards for aircraft 
engines. Such standards will be a central consideration in a future EPA 
regulation of aircraft engine emissions.
---------------------------------------------------------------------------

    \64\ ICAO, CAEP, Fourth Meeting, Montreal, Quebec, April 6-8, 
1998, Report, Document 9720, CAEP/4. Copies of this document can be 
obtained from the ICAO Web site located at http://www.icao.int.
---------------------------------------------------------------------------

    We believe this approach is the most appropriate means to address 
emissions from aircraft engines in this rulemaking. It codifies current 
practice, with no significant lead time, as a near-term approach.\65\ 
EPA has authority to revise emission standards from ``time to time.'' 
EPA intends to address more stringent emission standards requiring more 
lead time in a future rulemaking (see section III.A.5 for further 
discussion of future standards), as the ICAO and CAEP process develops 
progressively more stringent standards.
---------------------------------------------------------------------------

    \65\ As described later, more information and greater lead time 
would be necessary to require more stringent standards.
---------------------------------------------------------------------------

1. Today's NO<INF>X</INF> Standards
    EPA is adopting standards equivalent to ICAO's 1999 NO<INF>X</INF> 
emission standards for newly certified aircraft gas turbine engines 
(turbofan and turbojet engines) of rated thrust or output greater than 
26.7 kilonewtons (kN) with compliance dates as follows:\66\
---------------------------------------------------------------------------

    \66\ This includes standards for low-, mid-, and high-thrust 
engines (see below for further discussion of the different standards 
based on the thrust of the engines).
---------------------------------------------------------------------------

    For engines of a type or model of which that date of manufacture of 
the first individual production model was after December 31, 2003 (see 
below for further discussion on the effective date of these standards):
    (a) For engines with a pressure ratio of 30 or less:
    (i) For engines with a maximum rated output of more than 89.0 kN:

NO<INF>X</INF> = (19 + 1.6(rated pressure ratio)) g/kN rated output

    (ii) For engines with a maximum rated output of more than 26.7 kN 
but not more than 89.0 kN:

NO<INF>X</INF> = (37.572 + 1.6(rated pressure ratio)--0.2087(rated 
output))g/kN rated output

    (b) For engines with a pressure ratio of more than 30 but less than 
62.5:

    (i) For engines with a maximum rated output of more than 89.0 kN:
NO<INF>X</INF> = (7 + 2.0(rated pressure ratio)) g/kN rated output

    (ii) For engines with a maximum rated output of more than 26.7 kN 
but not more than 89.0 kN:

NO<INF>X</INF> = (42.71 + 1.4286(rated pressure ratio)--0.4013(rated 
output) + 0.00642(rated pressure ratio x rated output))g/kN rated 
output

    (c) For engines with a pressure ratio of 62.5 or more:

NO<INF>X</INF> = (32 + 1.6(rated pressure ratio)) g/kN rated output.

    The NO<INF>X</INF> emission standards presented above are 
equivalent to the ICAO NO<INF>X</INF> standards that have an 
implementation date of December 31, 2003.\67\ However, since this date 
has passed, the NO<INF>X</INF> emission standards prescribed above for 
newly certified engines shall take effect as prescribed beginning 
December 19, 2005.
---------------------------------------------------------------------------

    \67\ ICAO's CAEP/4 NO<INF>X</INF> standards became effective 
July 19, 1999, and applicable as of November 4, 1999. December 31, 
2003 is the implementation date for these standards. However, for 
the purpose of this Notice the effective date is considered the 
implementation date. (ICAO, ``Aircraft Engine Emissions,'' 
International Standards and Recommended Practices, Environmental 
Protection, Annex 16, Volume II, Second Edition, July 1993--
Amendment 4, July 19, 1999.)
---------------------------------------------------------------------------

2. NO<INF>X</INF> Standards for Newly Certified Mid- and High-Thrust 
Engines
    EPA is adopting NO<INF>X</INF> standards for newly certified mid- 
and high-thrust engines (those engines designed and certified after the 
effective date of the regulations, which have a rated output or thrust 
greater than 89 kN) that generally represent about a 16 percent 
reduction (or increase in stringency) from the existing standard. (See 
section III.A.1(a)(i) and III.A.1(b)(i) above for the standards for 
mid- and high-thrust engines.) More specifically, at a rated pressure 
ratio of 30 the NO<INF>X</INF> standards represent a 16 percent 
reduction from the existing standard. At rated pressure ratios of 10 
and 20, the standards correspond to 27 and 20 percent reductions, 
respectively. In addition, at rated pressure ratios of 40 and 50, the 
NO<INF>X</INF> standards signify 9 and 4 percent reductions, 
respectively. Also, today's and existing standards are equivalent at a 
rated pressure ratio of 62.5. See Figure III.B-1 in section III.B for a 
comparison of today's NO<INF>X</INF> standards (equivalent to CAEP/4 
standards) to the existing standards (equivalent to CAEP/2 standards) .
3. NO<INF>X</INF> Standards for Newly Certified Low-Thrust Engines
    For newly certified low-thrust engines (engines with a thrust or 
rated output of more than 26.7 kN but not more than 89.0 kN), EPA is 
adopting near-term

[[Page 69675]]

NO<INF>X</INF> standards that are equivalent to CAEP/4 standards for 
such engines, and these standards are different than today's standards 
for mid- and high-thrust engines (engines with thrust greater than 89.0 
kN).\68\ In addition to rated pressure ratio, the standards for low-
thrust engines will also be dependent on an engine's thrust or rated 
output.\69\ (See section III.A.1(a)(ii) and III.A.1(b)(ii) for a 
description of these different standards.) For example, at a rated 
pressure ratio of 30 and a thrust of 58 kN (thrust level in the middle 
of 26.7 kN and 89 kN), these standards are an 8 percent reduction (or 
increase in stringency) from the existing standard compared to a 16 
percent reduction for the standards for mid- and high-thrust 
engines.\70\
---------------------------------------------------------------------------

    \68\ Today's NO<INF>X</INF> standards for low thrust or small 
engines specify that engines with a rated output or thrust at 26.7 
kN meet the existing standard, and engines with a rated output at 89 
kN meet today's (or CAEP/4) standards. For engines with rated 
outputs or thrust levels between 26.7 and 89 kN, a linear 
interpolation was made between the low range of the existing 
standard and the high range of today's standard based upon the rated 
output to determine the NO<INF>X</INF> limits for such engines. 
Thus, thrust dependent standards are being adopted for engines with 
rated output or thrust between 26.7 kN and 89 kN.
    \69\ The standards for mid- and high-thrust engines are 
dependent only on an engine's rated pressure ratio.
    \70\ Additional examples of the standards for low-thrust engines 
in comparison to the standards for mid- and high-thrust engines are 
provided below. At rated pressure ratios of 10 and 20 with a thrust 
of 58 kN, today's low-thrust engine standards are a 14 and 10 
percent reduction from the existing standard, respectively. Whereas, 
at these same rated pressure ratios, today's standards for mid- and 
high-thrust engines are 27 and 20 percent reductions. In addition, 
at rated pressure ratios of 40 and 50 with a thrust of 58 kN, these 
low-thrust engine standards signify a 5 and 2 percent reduction from 
the existing standard, respectively. In comparison, at these same 
rated pressure ratios, today's standards for mid- and high-thrust 
engines are 9 and 4 percent reductions.
---------------------------------------------------------------------------

    The existing standards were not set at a stringency level that 
created a need for low-thrust engines to have different requirements, 
but at the level of NO<INF>X</INF> stringency adopted today different 
requirements are considered necessary for such engines. Due to their 
physical size, it is difficult to apply the best NO<INF>X</INF> 
reduction technology to low thrust or small engines. The difficulty 
increases progressively as size is reduced (from around 89 kN).\71\ For 
example, the relatively small combustor space and section height of 
these engines creates constraints on the use of low NO<INF>X</INF> fuel 
staged combustor concepts which inherently require the availability of 
greater flow path cross-sectional area than conventional 
combustors.\72\ Also, fuel staged combustors need more fuel injectors, 
and this need is not compatible with the relatively lower total fuel 
flows of lower thrust engines. (Reductions in fuel flow per nozzle are 
difficult to attain without having clogging problems due to the small 
sizes of the fuel metering ports.) In addition, lower thrust engine 
combustors have an inherently greater liner surface-to-combustion 
volume ratio, and this requires increased wall cooling air flow. Thus, 
less air will be available to obtain acceptable turbine inlet 
temperature distribution and for emissions control.\73\ Since the 
difficulties increase progressively as engine thrust size is reduced, 
EPA believes it is appropriate to make a graded change in stringency of 
today's NO<INF>X</INF> standards for low-thrust engines.
---------------------------------------------------------------------------

    \71\ ICAO/CAEP, Report of Third Meeting, Montreal, Quebec, 
December 5-15, 1995, Document 9675, CAEP/3.
    \72\ ``The burner section of an aircraft engine, which contains 
the combustion chamber, burns a mixture of fuel and air, and 
delivers the resulting gases to the turbine at a temperature which 
will not exceed the allowable limit at the turbine inlet.'' (United 
Technologies Pratt and Whitney, ``The Aircraft Gas Turbine Engine 
and Its Operation,'' August 1998.)
    \73\ ICAO/CAEP Working Group 3 (Emissions), ``Combined Report of 
the Certification and Technology Subgroups,'' section 2.3.6.1, 
Presented by the Chairman of the Technology Subgroup, Third Meeting, 
Bonn, Germany, June 1995. A copy of this paper can be found in 
Docket OAR-2002-0030.
---------------------------------------------------------------------------

4. Rationale for Today's NO<INF>X</INF> Standards for Newly Certified 
Low-, Mid-, and High-Thrust Engines
    Today's standards for low-, mid-, and high-thrust engines, which 
are equivalent to the CAEP/4 standards, ensure that new engine designs 
will incorporate the existing combustor technology and will not perform 
worse than today's current engines. This final rule to promulgate 
aircraft engine NO<INF>X</INF> standards equivalent to CAEP/4 standards 
is consistent with U.S. obligations under ICAO. By issuing standards 
that meet or exceed the minimum stringency levels of ICAO CAEP/4 
standards, we satisfy these obligations. (See section I.B for a 
discussion of the obligation of ICAO's participating nations). As 
indicated earlier, the implementation date, December 31, 2003, has 
already occurred for the CAEP/4 standards, and we need to promulgate 
the standards to meet our obligations for the CAEP/4 standards. 
Moreover, since we have already gone past the implementation date of 
the ICAO/CAEP/4 standards, there is not sufficient lead time to require 
more stringent emission standards in the very near term. As discussed 
later in section III.A.5 for future standards, we plan to address 
whether to take action on more stringent NO<INF>X</INF> standards in 
the future because pursuant to section 231(b) of the CAA we need more 
time to better understand the cost of compliance with such standards 
(see section III.A.5 for further discussion regarding lead time). Also, 
see the Summary and Analysis of Comments for this rulemaking for 
further discussion of this near-term approach.
    EPA believes that today's standards will not impose any additional 
burden on manufacturers, because manufacturers are already designing 
new engines to meet the ICAO international consensus standards by 2004 
(see section VIII of today's action for further discussion of 
regulatory impact). Even though the U.S. did not immediately adopt the 
ICAO NO<INF>X</INF> standards after 1999, engine manufacturers have 
continued to make progress in reducing these emissions. Today's 
standards are aimed at assuring that this progress is not reversed in 
the future.
    We received a number of comments from state and local governments 
and environmental groups stating that the NO<INF>X</INF> standards 
should be technology-forcing standards (a performance level that is 
beyond what sources are currently achieving). They stated that the 
standards are not technology forcing since 94 percent of all engine 
models currently in production already meet the standards (85 percent 
did in 1999 when the ICAO adopted the standards). Also, state and local 
governments and environmental groups stated that since the standards 
are not technology-forcing and most engines already meet the standards, 
aircraft engine NO<INF>X</INF> will increase. They expressed concern 
the many states are facing air quality challenges with implementation 
of the new 8-hour ozone national ambient air quality standards (NAAQS). 
Decreases in ozone and its precursors, including NO<INF>X</INF>, 
requires controls of emissions from all sectors, in addition to 
controls already implemented for 1-hour ozone NAAQS. For nonattainment 
areas, aircraft emissions are problematic, and the standards will not 
reduce aircraft emissions or address aircraft NO<INF>X</INF> pollution.
    Engine and airframe manufacturers and airlines supported the 
standards and opposed the concept of technology-forcing standards. 
Airlines indicated that the rulemaking would codify aircraft emission 
standards determined to be technologically feasible. In addition, 
airlines expressed that technology-forcing standards would be contrary 
to the CAA. Aircraft engine emission standards adopted according

[[Page 69676]]

section 231 of the CAA must be based on what is technologically 
feasible, and the standards cannot be amended if the change would 
significantly increase noise or adversely affect safety. They suggested 
that a technology-forcing NO<INF>X</INF> standard could adversely 
affect noise and safety. In addition, they indicated that section 231 
of the Act is different from other sections of the CAA that call for 
technology-forcing standards. Airlines expressed that section 231 
requires that standards already be technologically feasible and not 
compromise noise and safety. In addition, airlines expressed that 
whether a ``standard is technologically feasible depends not just on 
whether it can be achieved in a laboratory setting, but whether it can 
be achieved on a range of actual aircraft engine and airframe 
combinations that are certified as airworthy, safe, and fully operable 
under flight conditions. Moreover, such demonstrated technology must be 
available for application over a sufficient range of newly certificated 
aircraft, not just on a few airframe/engine combinations.'' (See the 
Summary and Analysis of Comments of this rulemaking for further 
discussion of comments.)
    In response to these comments, we refer to sections 231(a)(2)(B) 
and (b) of the CAA. Section 231(b) requires that any emission standards 
``take effect after such period as the Administrator finds necessary 
(after consultation with the Secretary of Transportation) to permit the 
development and application of the requisite technology, giving 
appropriate consideration to the cost of compliance during such 
period.'' 42 U.S.C. 7571(b). Section 231(a)(2)(B) provides that the 
Administrator shall consult with the Administrator of the FAA on 
standards, and ``shall not change the aircraft engine emission 
standards if such change would significantly increase noise and 
adversely affect safety.'' 42 U.S.C. 7571(a)(2)(B). Future aircraft 
emission standards will involve appropriate consultations between EPA 
and the FAA in applying these provisions of the CAA.
    EPA also needs to have a technical basis for expecting the 
standards will be achievable in a specific period of time. While the 
statutory language of section 231 is not identical to other provisions 
in title II of the CAA that direct EPA to establish technology-based 
standards for various types of engines, EPA interprets its authority 
under section 231 to be somewhat similar to those provisions that 
require us to identify a reasonable balance of specified emissions 
reduction, cost, safety, noise, and other factors. See, e.g., Husqvarna 
AB v. EPA, 254 F.3d 195 (DC Cir. 2001) (upholding EPA's promulgation of 
technology-based standards for small non-road engines under section 
213(a)(3) of the CAA). However, we are not compelled under section 231 
to obtain the ``greatest degree of emission reduction achievable'' as 
per sections 213 and 202 of the CAA, and so EPA does not interpret the 
Act as requiring the agency to give subordinate status to factors such 
as cost, safety, and noise in determining what standards are reasonable 
for aircraft engines. Rather, EPA has greater flexibility under section 
231 in determining what standard is most reasonable for aircraft 
engines, and is not required to achieve a ``technology-forcing'' 
result. The fact that most engines already meet standards would not in 
itself mean that the standard is inappropriate, provided the agency has 
a reasonable basis after considering all the relevant factors for 
setting the standard (with an appropriate period of lead time for that 
standard) at a level that results in no actual emissions reduction from 
the baseline.
    By the same token, EPA does not agree that a technology-forcing 
standard would be precluded by section 231, in light of section 
231(b)'s forward-looking language. Nor would EPA have to demonstrate 
that a technology is currently available universally or over a broad 
range of aircraft in order to base a standard on the emissions 
performance of such technology--the Agency is not limited in 
identifying what is ``technologically feasible'' as what is already 
technologically achieved. However, EPA would, after consultation with 
the Secretary of Transportation, need to provide manufacturers 
sufficient lead time to develop and implement requisite technology. As 
section 231 conveys, there is an added emphasis on the consideration of 
safety (see, e.g., sections 231(a)(2)(B)(ii) (``The Administrator shall 
not change the aircraft engine emission standards if such change would 
[* * *] adversely affect safety''), 42 U.S.C. 7571(a)(2)(B)(ii), and 
231(c) (``Any regulations in effect under this section [* * *] shall 
not apply if disapproved by the President, after notice and opportunity 
for public hearing, on the basis of a finding by the Secretary of 
Transportation that any such regulation would create a hazard to 
aircraft safety''), 42 U.S.C. 7571(c). Therefore, it is reasonable for 
EPA to give greater weight to considerations of safety in this context 
than it might in balancing emissions reduction, cost, and energy 
factors under other title II provisions.
    EPA is aware that many states face air quality challenges in light 
of the new ozone NAAQS, and since section 233 of the CAA vests 
authority only in EPA to set aircraft emission standards, we understand 
their perspective regarding the importance of setting more stringent 
NO<INF>X</INF> standards in the future. For these future standards, we 
expect to adopt standards developed through the CAEP process in ICAO. 
Further, federal agencies plan on working through the environmental 
Integrated Product Team for the Next Generation Air Transportation 
System (NGATS), to conduct a review of technology for aircraft engines 
and the resulting trend in aircraft emissions as well as 
interrelationships with noise (e.g., standards effect on projected 
aircraft emissions growth and expected effects on noise). See section 
III.A.5 below for further discussion of future NO<INF>X</INF> 
standards. (See the Summary and Analysis of Comments of this rulemaking 
for further discussion of our responses to comments.)
5. Future NO<INF>X</INF> Standards for Newly Certified Low-, Mid-, and 
High-Thrust Engines
    More stringent standards for low-, mid-, and high-thrust engines 
will likely be necessary and appropriate in the future. As discussed 
earlier in section II, the growth in aircraft emissions is projected to 
occur at a time when other mobile source categories are reducing 
emissions.\74\ The 1999 EPA study of commercial aircraft activity in 
ten cities projected that the aircraft NO<INF>X</INF> emissions would 
double in some of these cities by 2010, and the aircraft component of 
the regional mobile source NO<INF>X</INF> emissions in the ten cities 
would grow from a range of 1 to 4 percent that existed in 1990 to a 
range of 2 to 10 percent in 2010.\75\ As

[[Page 69677]]

indicated earlier, the above projections were made prior to the tragic 
events of September 11, 2001, and the economic downturn. A January 2003 
report by the Department of Transportation indicated that the 
combination of the September 11, 2001 terrorist attacks and a cut-back 
in business travel had a significant and perhaps long-lasting effect on 
air traffic demand. While, the FAA expects the demand for air travel to 
recover, and then continue a long-term trend of annual growth in the 
United States, it will grow at a lower rate and from a lower base than 
originally forecast. More recently, as discussed earlier, FAA reports 
that flights (or activity) of commercial air carriers and commuters/air 
taxis will increase by 22 percent from 2000 to 2015, about 12 percent 
less than what was forecast before September 11th.\76\ While flight 
activity, and thus NO<INF>X</INF> emissions, will be lower than 
originally anticipated, the relative size of the contribution of 
aircraft to national NO<INF>X</INF> levels may increase due to the 
potential decreased contribution from other mobile sources; hence, 
further action may be necessary in the future to reduce aircraft 
NO<INF>X</INF> emissions in nonattainment areas.
---------------------------------------------------------------------------

    \74\ The projected growth in aircraft emissions is not simply 
from the number of operations, but it could also be attributed to 
the change in the types of aircraft being operated. For example, 
regional aircraft activity is growing (regional aircraft are 
generally referred to as those aircraft with more than 19 but fewer 
than 100 seats--regional jets and turboprops). In the U.S., traffic 
flown by regional airlines increased about 20 percent in 1999 and is 
expected to grow approximately 7 percent annually during the next 
ten years, compared to 4 to 6 percent for the major airlines. In 
addition, regional jets comprised about 25 percent of the regional 
aircraft fleet in 2000, up from only 4.2 percent in 1996, and their 
fraction of the fleet is expected to increase to nearly 50 percent 
by 2011. (R. Babikian, S. P. Lukachko and I. A. Waitz, ``Historical 
Fuel Efficiency Characteristics of Regional Aircraft from 
Technological, Operational, and Cost Perspectives,'' Journal of Air 
Transport Management, Volume 8, No. 6, pp. 389-400, Nov. 2002.)
    \75\ U.S. EPA, ``Evaluation of Air Pollutant Emissions from 
Subsonic Commercial Jet Aircraft,'' April 1999, EPA420-R-99-013. 
This study is available at http://www.epa.gov/otaq/aviation.htm. It 
can also be found in Docket No. OAR-2002-0030.
    \76\ U.S. FAA, ``APO Terminal Area Forecast Summary Report,'' 
Aircraft Operations, June 30, 2005. The flight forecast data is 
based on FAA's Terminal Area Forecast System (TAFS). TAFs is the 
official forecast of aviation activity at FAA facilities. This 
includes FAA-towered airports, federally-contracted towered 
airports, nonfederal towered airports, and many non-towered 
airports. For detailed information on TAFS and the air carrier 
activity forecasts see the following FAA website: http://www.apo.data.faa.gov/main/taf.asp. The June 30, 2005 aviation 
forecasts contained in TAFS for Fiscal Years 2002-2020 included the 
impact of the terrorists' attacks of September 11, 2001 and the 
recent economic downturn. Currently, the aviation industry is 
undergoing significant structural and economic changes. These 
changes may necessitate revisions to forecasts for a number of large 
hub airports prior to the update of the entire TAF next year. A copy 
of the June 30, 2005 forecast summary report can also be found in 
Docket No. OAR-2002-0030.
---------------------------------------------------------------------------

    Further stringency of the NO<INF>X</INF> standards would reduce the 
expected growth in commercial aircraft NO<INF>X</INF> emissions. The 
importance of controlling aircraft emissions has grown in many areas 
(especially areas not meeting the 1-hour and 8-hour ozone NAAQS) as 
controls on other sources become more stringent and attainment of the 
NAAQS's has still not been achieved. (Many airports in the U.S. are 
located in nonattainment areas.\77\) As activity increases, aircraft 
would emit increasing amounts of NO<INF>X</INF> in many nonattainment 
areas, and thus, aircraft NO<INF>X</INF> emissions would further 
aggravate the problems in these areas (either by emitting pollutants 
directly within a nonattainment area or by contributing to regional 
transport emissions in an area upwind of a nonattainment area). More 
stringent aircraft engine NO<INF>X</INF> standards may assist in 
alleviating these problems in nonattainment areas, and they may aid in 
preventing future concerns in areas currently designated as attainment 
(or maintenance) areas. In addition, attainment or maintenance of the 
NAAQS may depend upon aircraft engines being subject to a program of 
control compatible with their significance as pollution sources. (See 
the Summary and Analysis of Comments for this rulemaking for further 
discussion of future standards and the environmental need for control.)
---------------------------------------------------------------------------

    \77\ For information on the geographic location of airports, see 
the following U.S. Department of Transportation (Bureau of 
Transportation Statistics) website: http://www.bts.gov/oai. The 
report or database provided on the website entitled, ``Airport 
Activity Statistics of Certificated Air Carriers: Summary Tables 
2000,'' lists airports by community. In addition, see the following 
EPA website for information on nonattainment areas for criteria 
pollutants: http://www.epa.gov/oar/oaqps/greenbk.
---------------------------------------------------------------------------

    EPA, therefore, is considering the exploration of more stringent 
future standards, beyond today's standards. Earlier this year, the ICAO 
Council adopted more stringent international consensus NO<INF>X</INF> 
emission standards for newly certified aircraft engines (implementation 
date of after December 31, 2007).\78\ The CAEP/6 NO<INF>X</INF> 
standards generally represent about a 12 percent increase in stringency 
from the standards promulgated in this final rule (or the CAEP/4 
NO<INF>X</INF> standards).\79\ (These standards were accompanied by 
more stringent standards for low-thrust engines). Moreover, CAEP agreed 
to review the stringency of the NO<INF>X</INF> standards again during 
the work program for the eighth meeting of CAEP, which will commence in 
early 2007 and is expected to culminate in early 2010. Such standards 
will be a central consideration in a future EPA regulation of aircraft 
engine emissions. Thus, it will be important that the U.S. continue to 
actively participate in the technical emissions work activity that will 
endeavor to establish the technological basis for any increase in 
stringency that CAEP will contemplate. We believe this ongoing phased 
approach is the most appropriate means to address emissions from 
aircraft engines.
---------------------------------------------------------------------------

    \78\ ICAO News Release, ``ICAO Council Adopts New Standards for 
Aircraft Emissions,'' PIO 03/05, March 2, 2005. Copies of this 
document can be obtained at the ICAO website located at http://www.icao.int.
    \79\ ICAO, CAEP, Sixth Meeting, Montreal, Quebec, February 2-12, 
2004, Report, Letter of Transmittal to the President of the Council 
From the Chairman of the Sixth Meeting of CAEP, CAEP/6-WP/57 (Report 
on Agenda Item 1). Copies of this document can be obtained from ICAO 
(http://www.icao.int). It can also be found in Docket No. OAR-2002-
0030.
---------------------------------------------------------------------------

    As we discussed in the proposal, activity is also underway in CAEP 
to identify and assess the potential for long-term technology goals to 
be established for further emission reductions, including implementing 
a CAEP-approved process to set and review these goals.<SUP>80 81</SUP> 
The aim of the goal setting activity is to complement the ICAO CAEP 
standard setting process with information to aid the engine and 
airframe manufacturer's design process. The goals are expected to take 
into account the results of recently completed emissions reduction 
technology programs such as those conducted by National Aeronautics and 
Space Administration (NASA) and the European Commission and the 
timeline necessary to carry those technologies from the research phase 
through commercialization.\82\ We support this CAEP work item for 
establishing goals. However, this should not be interpreted as 
agreement on our part that the CAEP process is the exclusive 
appropriate process for setting aircraft emissions reduction goals or 
for encouraging the development of better performing technology. For 
example, the Next Generation Air Transportation System

[[Page 69678]]

(NGATS) plan was released in December 2004--a Congressionally chartered 
and Administration endorsed activity to develop research and plans to 
transform the air transportation system. Efforts there will include 
assessment of various technological and operational procedures to 
reduce aircraft emissions, including NO<INF>X</INF>, as well as a 
thorough assessment of interrelationships between noise and emissions 
and amongst emissions to enable maximizing environmental benefit 
derived from mitigating actions. Further, in EPA's long history of 
mobile source regulation, we have found that performance-based 
standards have been successfully used to stimulate technological 
development resulting in cleaner, cost-effective, and safe engines.
---------------------------------------------------------------------------

    \80\ ICAO, CAEP, Sixth Meeting, Montreal, Quebec, February 2-12, 
2004, Report, Letter of Transmittal to the President of the Council 
From the Chairman of the Sixth Meeting of CAEP, CAEP/6-WP/57 (Report 
on Agenda Item 4). Copies of this document can be obtained from ICAO 
(http://www.icao.int). It can also be found in Docket No. OAR-2002-
0030.
    \81\ For the purposes of setting long-term technology goals for 
aircraft emission reductions, the CAEP/6 (occurred in February 2004) 
future work program included the following items:
    (a) Implement a CAEP-approved process to set, periodically 
review and update technology goals and identify environmental 
benefits, taking into account progress in ongoing research and 
development efforts toward reducing aircraft emissions, 
environmental interdependencies and trade-offs, and scientific 
understanding of the effects of aircraft engine emissions;
    (b) Support and monitor development and methods for 
understanding the inter-relationship of technology goals targeting 
individual emissions performance improvements; and
    (c) Develop the inputs appropriate for use of air quality and 
climate impact models to be used by CAEP to quantify the value of 
emissions reduction and to estimate the benefit from long-term 
goals.
    ICAO, CAEP, Sixth Meeting, Montreal, Quebec, February 2-12, 
2004, Report, Letter of Transmittal to the President of the Council 
From the Chairman of the Sixth Meeting of CAEP, CAEP/6-WP/57 
(Appendix A to the Report on Agenda Item 4--Revised Work Program for 
CAEP, page 4A-7). Copies of this document can be obtained from ICAO 
(http://www.icao.int). It can also be found in Docket No. OAR-2002-
0030.
    \82\ ICAO, CAEP, Fourth Meeting, Montreal, Quebec, April 6-8, 
1998, Report, Document 9720, CAEP/4, see Appendix A to the Report on 
Agenda Item 4 (page 4-A-1). Copies of this document can be obtained 
from ICAO (http://www.icao.int).
---------------------------------------------------------------------------

    Manufacturers should be able to achieve additional reductions with 
more lead time than is provided by today's action. As we discussed in 
the proposal, in the future we intend to assess, in coordination with 
the NGATS Environmental Integrated Product Team (IPT) whether or not 
the new international consensus and longer-term standards, CAEP/6 
NO<INF>X</INF> standards, would be stringent enough to protect the U.S. 
public health and welfare. If so, we would plan to propose to adopt the 
CAEP/6 NO<INF>X</INF> standards. EPA in consultation with the Secretary 
of Transportation retains the discretion to adopt more stringent 
NO<INF>X</INF> standards in the future if the international consensus 
standards ultimately prove insufficient to protect U.S. air quality. As 
discussed earlier, the implementation date, December 31, 2003, has 
already occurred for the CAEP/4 standards, and we need to promulgate 
today's standards to meet our obligations for the CAEP/4 standards. 
This final rule to promulgate aircraft engine NO<INF>X</INF> standards 
equivalent to CAEP/4 standards is consistent with U.S. obligations 
under ICAO. We would not be able to quickly adopt a more stringent 
standard. However, we intend to consider further stringency in a future 
rulemaking. In addition, we have not yet assessed the costs (and 
emission benefits) of more stringent standards, but we anticipate doing 
so in the future for such standards.
    Consideration of more stringent NO<INF>X</INF> standards in the 
future will allow us to obtain important additional information on the 
costs of such standards.\83\ As described earlier, section 231 of the 
CAA authorizes EPA from ``time to time'' to revisit emission standards, 
and it requires that any standards' effective dates permit the 
development of necessary technology, giving appropriate consideration 
to the cost. We did not propose more stringent NO<INF>X</INF> standards 
primarily because we needed more time to better understand the cost of 
compliance of such standards. Cost data is now available from CAEP/6 
(meeting occurred in February 2004), but we need to first adopt the 
standards equivalent to CAEP/4 today since we have already gone past 
the CAEP/4 implementation date. Although, as we described earlier, the 
CAEP/6 NO<INF>X</INF> standards will be a central consideration in a 
future aircraft engine emission standards, other levels of further 
stringency would also be under consideration, and additional cost 
information for such standards would need to be evaluated.
---------------------------------------------------------------------------

    \83\ For low-thrust engines, deferring regulatory action on more 
stringent future standards until after CAEP/6 would also enable us 
to obtain additional information on the technological feasibility of 
such standards.
---------------------------------------------------------------------------

    As we discussed in the proposal, producing (and/or developing) new 
engines or engine technologies requires significant financial 
investments from engine manufacturers, which takes time to recoup (the 
amount of time depends upon sales of engines, replacement parts, etc.). 
After evaluating additional cost information for future standards as 
well as other emissions reduction approaches, we would then be better 
situated to make decisions on an appropriate level of stringency and 
implementation timing that maximizes NO<INF>X</INF> reductions from 
aircraft engines, taking into consideration cost, safety, and noise.

B. Newly Manufactured Engines of Already Certified Models

    We requested comment on whether the NO<INF>X</INF> standards would 
apply to newly manufactured engines of already certified models (i.e., 
those individual engines that are part of an already certified engine 
model, but are built after the effective date of the regulations for 
such engines and have never been in service),\84\ but after careful 
consideration and reviewing comments from stakeholders, we have decided 
not to include such engines in today's final rulemaking. It is 
important to mention that CAEP/6 did not adopt provisions to apply the 
CAEP/4 NO<INF>X</INF> standards to newly manufactured engines of 
already certified models (a production cut-off). CAEP/6 noted the 
industry view that market forces are the primary drivers of the 
development and incorporation of new technology (asserting voluntary 
compliance would suffice), and an understanding at CAEP/4 that a 
production cut-off would not be introduced in the future. CAEP/6, after 
reviewing that commitment, decided that ``* * *this should not be 
interpreted as meaning that production cut-offs would not be introduced 
in the future if the situation so warranted.''<SUP>85 86</SUP> (As we 
discussed in the proposal, CAEP's Forecasting and Economic Analysis 
Support Group (FESG) further analyzed applying CAEP/4 NO<INF>X</INF> 
standards to newly manufactured engines of already certified models for 
CAEP/6, and assessed effective dates of 2, 4, and 6 years after 
December 31, 2003, which is the implementation date for newly certified 
engines.\87\ FESG estimated that the cost per ton of NO<INF>X</INF> 
reduced would range from $3,800 to $11,200 for the three effective 
dates.\88\ The emission benefits and costs of this provision are 
discussed further below.)
---------------------------------------------------------------------------

    \84\ This provision does not mean the re-certification or 
retrofit of existing in-use engines. Instead the provision would 
require the ongoing production of engines that have already been 
certified to meet the new standards, rather than following CAEP/4 
and merely applying today's standards to future engine designs and 
allowing currently produced engine models to meet the previous 
standards.
    \85\ ICAO, CAEP, Sixth Meeting, Montreal, Quebec, February 2-12, 
2004, Report, Letter of Transmittal to the President of the Council 
From the Chairman of the Sixth Meeting of CAEP, CAEP/6-WP/57 (Report 
on Agenda Item 1). A copy of this document can be found in Docket 
No. OAR-2002-30.
    \86\ CAEP/6 noted that industry ``pointed out that introduction 
of a production cut-off now would cause the manufacturer to modify 
engines to meet the CAEP/4 standards, whereas if no cut-off were 
imposed it was likely that they could be modified to meet the new 
standards agreed at this meeting.'' (ICAO, CAEP, Sixth Meeting, 
Montreal, Quebec, February 2-12, 2004, Report, Letter of Transmittal 
to the President of the Council From the Chairman of the Sixth 
Meeting of CAEP, CAEP/6-WP/57, Report on Agenda Item 1, pages 1-13.)
    \87\ ICAO, CAEP/6, Information Paper 28--Appendix B, ``FESG 
Economic Assessment of Applying a Production Cut-off to the CAEP/4 
NO<INF>X</INF> Standard'' Presented by the FESG Rapporteur, January 
29, 2004 (Same as CAEP-SG20031-IP/9, which was presented at June 10, 
2003 CAEP Steering Group Meeting). A copy of this document can be 
found in Docket No. OAR-2002-30.
    \88\ ICAO, CAEP/6, Information Paper 28--Appendix B, ``FESG 
Economic Assessment of Applying a Production Cut-off to the CAEP/4 
NO<INF>X</INF> Standard'' Presented by the FESG Rapporteur, January 
29, 2004 (Same as CAEP-SG20031-IP/9, which was presented at June 10, 
2003 CAEP Steering Group Meeting). A copy of this document can be 
found in Docket No. OAR-2002-30.
---------------------------------------------------------------------------

1. What Is the Status of Engines?
    According to the ICAO Aircraft Engine Exhaust Emissions Data 
Bank,\89\ nearly all already certified engine models (95 percent of 
already certified

[[Page 69679]]

and in-production engine models in the Data Bank) currently meet or 
perform better than the standards we are adopting today.\90\ (See 
Figure III.B-1 below for a comparison of the NO<INF>X</INF> emission 
levels of current in-production engines to the CAEP/4 NO<INF>X</INF> 
standards.\91\) At the time the CAEP/4 NO<INF>X</INF> standards were 
adopted in 1998, all but 11 in-production engines and 5 newly designed 
engine models (these 5 engines were in the design and development 
process in 1998) had NO<INF>X</INF> emission levels that would perform 
better than the CAEP/4 standards.\92\ Today, nearly all of the engines 
that did not meet the CAEP/4 NO<INF>X</INF> standard in 1998 now 
comply, except for the JT8D-200 engine family.\93\ The other engine 
models have either, through additional testing or modifications, been 
improved to meet the standards or the engines are no longer in-
production. Although, as described earlier, the ICAO Data Bank shows 
that eight engine models or three different Pratt and Whitney engine 
types or families do not meet the NO<INF>X</INF> standards, we now know 
that except for the JT8D-217 and JT8D-219, six of the engine models or 
two of the engine types are compliant.
---------------------------------------------------------------------------

    \89\ International Civil Aviation Organization (ICAO), Aircraft 
Engine Exhaust Emissions Data Bank, July 26, 2004. This data bank is 
available at http://www.caa.co.uk/default.aspx?categoryid=702&pagetype=90. In addition, a copy of a 
table including data of engine NO<INF>X</INF> emissions from the 
ICAO data bank and their margin to today's NO<INF>X</INF> standards 
can be found in Docket OAR-2002-0030.
    \90\ Based on the ICAO Data Bank, 151 out of 159 (95 percent) 
engine models that are currently in production perform better than 
the CAEP/4 NO<INF>X</INF> standards. The 8 engine models (which are 
mid- and high-thrust engines) that are not achieving the CAEP/4 
NO<INF>X</INF> standards are from three different Pratt and Whitney 
(PW) engine types or families (engines and their thrust variants 
with the same build standard). These engines are the following: (1) 
JT8D-217C E-kit and JT8D-219 E-kit; (2) PW4077D, PW4084D, and 
PW4090; and (3) PW4164, PW4168, and PW4168A. (See Figure III.B-1 
below that specifically shows these 8 in-production models in 
relation to the CAEP/4 or proposed NO<INF>X</INF> standards.) For 
the year 2000, these 8 engine models were found on approximately 751 
out of 20,137 (3.7 percent) aircraft owned by U.S. carriers and 
accounted for approximately 1,541,172 out of 11,505,063 (13.4 
percent) of U.S. domestic flights.
    \91\ For Figure III.B-1, the Allison, Pratt and Whitney (does 
not include JT8D-217C E-kit and JT8D-219 E-kit), Rolls-Royce, and 
Textron Lycoming engines with rated pressure ratios less than or 
equal to 20 and NO<INF>X</INF> levels above the CAEP/4 
NO<INF>X</INF> standards actually perform better than the standards, 
since there are different CAEP/4 NO<INF>X</INF> standards for these 
low-thrust engines (see section III.A.3 for further discussion of 
NO<INF>X</INF> standards for low thrust engines). (47 of the 159 
engines, 30 percent of engine models in production, in Figure IV.B-1 
and the ICAO Aircraft Engine Exhaust Emissions Data Bank are low-
thrust engines--engines with thrust greater than 26.7 kN but not 
more than 89 kN.)
    \92\ ICAO, CAEP/4, Working Paper 4, ``Economic Assessment of the 
EPG NO<INF>X</INF> Stringency Proposal,'' March 12, 1998, Presented 
by the Chairman of Forecasting and Economic Analysis Support Group 
(FESG), Agenda Item 1: Review of proposals relating to 
NO<INF>X</INF> emissions, including the amendment of Annex 16, 
Volume II, See Table 3.1 of paper. A copy of this paper can be found 
in Docket OAR-2002-0030.
    \93\ ICAO, CAEP/6, Working Paper 34, ``NO<INF>X</INF> Production 
Cut-off Consideration,'' Presented by the International Coordinating 
Council of Aerospace Industries Associations (ICCAIA), January 6, 
2004. A copy of this document can be found in Docket No. OAR-2002-
30.
---------------------------------------------------------------------------

    (The above reference for the fleet fraction is BACK Aviation 
Solutions, http://www.backaviation.com/Information_Services/default.htm.
    The domestic flight information is based on SAGE, the System for 
Assessing Aviation Emissions. SAGE is an FAA model that estimates 
aircraft emissions through the full flight profile using non-
proprietary input data, such as BACK, FAA's Enhanced Traffic Management 
System (ETMS), and the Official Airline Guide (OAG). The year 2000 air 
traffic movements database portion of SAGE was used to estimate the 
number of flights using the subject engines.)
    The PW4090 family of engines (PW4077D, PW4084D, and PW4090) now has 
the means to eventually meet the standards utilizing technology that 
would meet the lower ranges of stringency options for the 
NO<INF>X</INF> standards considered at CAEP/6, although the 
manufacturer has projected it would be some years before it expects to 
meet CAEP/6 levels (the manufacturer has not provided us with a 
projected necessary lead-time to meet CAEP/4). The engine family that 
includes the PW4164, PW4168 and PW4168A engines is now certified with 
the PW 4168 Technologically Affordable Low NO<INF>X</INF> (Talon) II 
engine combustor technology, which performs significantly better than 
the CAEP/4 standards. Also, the JT8D-200 engine powers the MD-80 
aircraft, which is no longer in production. Yet, the JT8D-200 engine 
(JT8D-217C and JT8D-219 in-production engines) could potentially apply 
to future supersonic business jets. As stated in the proposal, the 
resulting NO<INF>X</INF> emission benefits of applying the standards to 
the JT8D-200 (for these possible supersonic business jets) would be 
expected to be very small, and the costs would also likely be 
relatively small on an industry wide basis, although as discussed 
further below we do not feel we have a sufficient record at this 
point--nor have we presented it for public comment--to state our 
definitive views on these issues. However, the direct (development) 
costs would most likely be borne by one engine manufacturer.\94\ As 
discussed in the proposal, there is only one remaining newly designed 
engine model--out of the five identified in 1998--that would be 
certified after 2003, and it also has been made compliant with today's 
or CAEP/4 NO<INF>X</INF> standards.\95\
---------------------------------------------------------------------------

    \94\ ICAO, CAEP/6, Information Paper 28--Appendix B, ``FESG 
Economic Assessment of Applying a Production Cut-off to the CAEP/4 
NO<INF>X</INF> Standard'' Presented by the FESG Rapporteur, January 
29, 2004 (Same as CAEP-SG20031-IP/9, which was presented at June 10, 
2003 CAEP Steering Group Meeting). A copy of this document can be 
found in Docket No. OAR-2002-30.
    \95\ The PW Canada growth engines are the one remaining type of 
newly designed engines. The ICAO Aircraft Engine Exhaust Emissions 
Data Bank currently does not have emissions certification data for 
such an engine, but Working Paper 34 presented at CAEP/6 indicated 
it would be compliant. (ICAO, CAEP/6, Working Paper 34, 
``NO<INF>X</INF> Production Cut-off Consideration,'' Presented by 
the International Coordinating Council of Aerospace Industries 
Associations (ICCAIA), January 6, 2004. A copy of this document can 
be found in Docket No. OAR-2002-30.)
---------------------------------------------------------------------------

    In addition, as we indicated in the proposal, if an already 
certified engine design meets the standards that we are adopting today, 
then it is unlikely that either existing or future engine designs built 
to that design or type (derivatives or thrust variants with the same 
build standard) would not meet these standards. However, we may have 
been imprecise by stating in the proposal that when design 
modifications are made to an existing engine type, then this engine 
type would likely need to be recertified. Derivative versions of 
engines are not typically required to meet new standards for newly 
certified (and newly designed) engines, but they usually need to comply 
with the same standards as were applied to the original engine 
model.<SUP>96 97</SUP> Thus, derivative versions of engines typically 
do not need to be recertified. However, an engine type that does need 
to recertified will be required to comply with the CAEP/4 and today's 
NO<INF>X</INF> standards.
---------------------------------------------------------------------------

    \96\ ICAO, CAEP/4, Information Paper 3, ``Clarification of the 
Definition of Derivative Version,'' Agenda Item 4--Future Work, 
Presented by United States, April 3, 1998. A copy of this document 
can be found in Docket No. OAR-2002-30.
    \97\ Chapter 1 of Part I of the ICAO Annex 16, Volume II, 
Aircraft Engine Emissions, defines derivative version as follows: 
``an aircraft gas turbine engine of the same generic family as an 
originally type-certificated engine and having features which retain 
the basic core engine and combustor design of the original model and 
for which other factors, as judged by the certificating authority, 
have not changed.''

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

[[Page 69680]]

[GRAPHIC] [TIFF OMITTED] TR17NO05.001

2. What Are the Issues With Applying Today's NO<INF>X</INF> Standards 
to Newly Manufactured Engines of Already Certified Models?
    One commenter expressed that EPA conceded in the proposed rule that 
it has historically applied aircraft emission standards to newly 
manufactured engines of already certified models, and doing so this 
time would prohibit the indefinite continued production of aircraft 
engines that would meet only the previous standards. ``EPA does not 
explain why it is proposing a sudden departure from the past practice 
of regulating already certified, newly manufactured engines--i.e., what 
is different about this particular rulemaking that justifies the 
exemption of such engines.'' With the long life of aircraft engines and 
the availability of newly manufactured engines of already certified 
models in the future, there is a need to apply the proposed 
NO<INF>X</INF> standards to this category of aircraft engines.
    State and local governments recommended that the standards for 
newly manufactured engines of already certified models should be 
implemented one year after the effective date of the final rulemaking. 
At a minimum, EPA should have an implementation date that prohibits 
engine manufacturers from selling already certified engines unless the 
engines were recertified or redesigned to meet the proposed standards. 
Such a provision would be consistent with a stated objective of the 
rulemaking, which is to assure that progress in reducing aircraft 
engine emissions is not reversed in the future. Without such standards 
high-emitting engines can continue to be produced and brought into 
service, further adding to the long-term growth in aircraft emissions 
that is anticipated without a more aggressive approach to regulating 
this source.
    Airlines commented that as the proposal acknowledges, market 
incentives lead manufacturers to bring their engines to the levels of 
the CAEP/4 NO<INF>X</INF> standards as soon as possible once the 
standards take effect. Airlines investing in costly, long-lasting 
assets prefer to buy engines that meet the latest standards, and demand 
engines that perform better than the standard without regulatory 
intervention of a production cut-off (applying standards to newly 
manufactured engines of already certified models). Such market forces 
together with EPA's four-year delay in proposing to adopt the CAEP/4 
NO<INF>X</INF> standards, account for the fact that 94 percent of in-
production engines already meet the standard.
    In addition, airlines expressed that for the same reasons that the 
Agency should generally align with ICAO standards, it should be 
consistent with ICAO on whether to apply CAEP/4 standards to newly 
manufactured engines of already certified models. If EPA differed from 
ICAO on this provision, there would be the very inconsistency between 
domestic and international practice that aligning with ICAO 
requirements avoids. Furthermore, if EPA adopts such a provision prior 
to ICAO, such action would potentially place U.S. manufacturers and 
airlines at a competitive disadvantage for what EPA acknowledges to be 
minimal environmental benefit.
    In addition, one airline expressed that it presently has the JT8D-
219 engine on some of its commercial jets. The proposal indicated that 
the JT8D-219 would be used in supersonic business jets, which the 
airline does not operate; however, it (and maybe other domestic 
airlines) operates this engine in our commercial aircraft fleet. 
Therefore, the implication of these provisions has not been fully 
investigated by EPA as mandated by the CAA. (See the Summary and 
Analysis of Comments for this rulemaking for further discussion of 
comments.)
    In response, as indicated earlier, the implementation date 
applicable to newly designed and certified engines under CAEP/4, 
December 31, 2003, has already occurred for the CAEP/4 standards, and 
at this late date to promulgate a provision to apply today's standards 
to newly manufactured engines of already certified models (a production 
cut-off) could be disruptive to the production planning of engine

[[Page 69681]]

manufacturers. EPA and ICAO (as we mentioned in the proposal and as one 
commenter noted in its comments) have historically adopted production 
cut-offs for previous standards, but in today's unique case the 
lateness of the rule may not provide manufacturers enough lead time for 
such planning. However, as we discussed earlier, we intend to consider 
more stringent NO<INF>X</INF> standards in a future rulemaking, and 
similar to CAEP/6's future plans described above, we also intend to 
consider applying more stringent standards to newly manufactured 
engines of already certified models for such a future rulemaking. This 
provision is an important issue that we expect to fully consider for 
future standards.
    While we solicited comment on extending the CAEP/4 standards to 
newly manufactured engines of already certified models, we did not 
develop a record that fully analyzes the emissions benefits (if any) 
and the implementation costs of going beyond CAEP in this manner. 
Therefore, the public has not been provided an opportunity to analyze 
and comment upon these important factors. We believe that our analysis 
of these factors would need to be weighed through a notice-and-comment 
process in determining whether a production cut-off, with a specific 
lead-time period, would be appropriate under CAA section 231 in this 
case. Particularly regarding the cost of compliance within necessary 
lead-time issue, we are concerned that there is insufficient data that 
specifically addresses the appropriate lead time for subjecting the few 
remaining in-production engine models to the CAEP/4 standards, and that 
our selection of a production cut-off date could therefore be viewed as 
arbitrarily chosen.
    Since we have not yet provided that opportunity for public comment 
on our analysis of this issue, and since attempting to do so now would 
in our view unacceptably slow down this rulemaking, in the interests of 
expediency and of bringing U.S. domestic law into conformity with our 
obligations under the Chicago Convention (albeit tardily), we have 
decided that the most appropriate course for now, under CAA section 231 
(a), is to simply update our regulations to track CAEP/4 in terms of 
both stringency levels and scope of applicability. Similarly, without 
having developed the necessary record and analysis, at this time we are 
unable to respond to the substantive comments offered by commenters 
regarding the production-cutoff issue, and our decision today should in 
no way be viewed as either endorsing or rejecting the concept of a 
production cut-off. Given the need to quickly promulgate standards that 
are at least as stringent as CAEP/4, we must decline to resolve the 
numerous issues raised either in favor of or in opposition to applying 
the CAEP/4 standards to newly manufactured engines of already certified 
models.

IV. Amendments to Criteria on Calibration and Test Gases for Gaseous 
Emissions Test and Measurement Procedures

    In today's rulemaking, EPA will incorporate by reference ICAO's 
1997 amendments to the criteria on calibration and test gases for the 
test procedures of gaseous emissions (ICAO International Standards and 
Recommended Practices Environmental Protection, Annex 16, Volume II, 
``Aircraft Engine Emissions,'' Second Edition, July 1993; Amendment 3, 
March 20, 1997, Appendices 3 and 5) in 40 CFR 87.64. ICAO's amendments, 
which became effective on March 20, 1997, apply to subsonic (newly 
certified and newly manufactured engines \98\) and supersonic gas 
turbine engines. The technical changes will correct a few 
inconsistencies between the specifications for carbon dioxide 
(CO<INF>2</INF>) analyzers (Attachment B of Appendices 3 and 5) and the 
calibration and test gases (Attachment D of Appendices 3 and 5) of 
gaseous emissions. The test procedure amendments incorporated by 
reference will be effective 30 days after the publication of the final 
rule.
---------------------------------------------------------------------------

    \98\ Such engines include newly manufactured engines of already 
certified models.
---------------------------------------------------------------------------

    For CAEP/3 in 1995, the Russian Federation presented a working 
paper entitled, ``Corrections to Annex 16, Volume II,'' that stated the 
following: \99\
---------------------------------------------------------------------------

    \99\ Russian Federation, ``Corrections to Annex 16, Volume II,'' 
Agenda Item 2: Review of reports of working groups relating to 
engine emissions and the development of recommendations to the 
Council thereon, Working Paper 19, Presented by A.A. Gorbatko, 
November 11, 1995 (distributed November 30, 1995), CAEP/3, Montreal, 
December 5 to 15, 1995. A copy of this paper can be found in Docket 
OAR-2002-0030.

    According to CAEP/2 recommendations, in the list of calibration 
and test gases (see the table in Attachment of Appendices 3 and 5) 
``CO<INF>2</INF> in N<INF>2</INF>'' was replaced with 
``CO<INF>2</INF> in air'' gas. At the same time the following sub-
paragraph was newly introduced into Attachment B (Appendices 3 and 
5) :
    (g) The effect of oxygen (O<INF>2</INF>) on the CO<INF>2</INF> 
analyzer response shall be checked. For a change from 0 percent 
O<INF>2</INF> to 21 percent O<INF>2</INF> the response of a given 
CO<INF>2</INF> concentration shall not change by more than 2 per 
cent of reading. If this limit cannot be met an appropriate 
correction factor shall be applied.
    Since the best way to carry out this checking procedure is to 
calibrate the analyzer first with CO<INF>2</INF> in nitrogen and 
then with CO<INF>2</INF> in air, both ``CO<INF>2</INF> in 
N<INF>2</INF>'' and ``CO<INF>2</INF> in air'' gases have to be 
retained in the list. It seems then that ``CO in air,'' 
``CO<INF>2</INF> in air,'' ``NO in N<INF>2</INF>'' and now 
``CO<INF>2</INF> in N<INF>2</INF>'' have to be replaced with ``CO in 
zero air,'' ``CO<INF>2</INF> in zero air,'' ``CO<INF>2</INF> in zero 
nitrogen'' and ``NO in zero nitrogen'' just by analogy with the 
gaseous mixtures of different hydrocarbons diluted by zero air and 
listed in the same table.

    In addition, at CAEP/3 the United Kingdom then presented a working 
paper on this same issue.\100\ They indicated that CAEP's Working Group 
3 (Emissions Working Group) had accepted the above proposals of the 
Russian Federation paper on correcting inconsistencies in the list of 
calibration and test gases specified in Annex 16, Volume II, Attachment 
D to Appendices 3 and 5, and Working Group 3 had recommended that these 
proposals be presented at CAEP/3. The United Kingdom also recommended 
the adoption of these Russian Federation proposals--to utilize 
CO<INF>2</INF> in nitrogen gas mixture to check the effect of oxygen on 
CO<INF>2</INF> analyzers. In addition, they recommended the 
specification of all calibration and test gases required for all the 
gaseous emissions tests required in Annex 16.
---------------------------------------------------------------------------

    \100\ United Kingdom, ``Amendments to Annex 16, Volume II, 
Attachment D to Appendices 3 and 5 (Calibration and Test Gases),'' 
Agenda Item 2: Review of reports of working groups relating to 
engine emissions and the development of recommendations to the 
Council thereon, Working Paper 20, Presented by M.E. Wright, 
November 14, 1995 (distributed November 30, 1995), CAEP/3, Montreal, 
December 5 to 15, 1995. A copy of this paper can be found in Docket 
OAR-2002-0030.
---------------------------------------------------------------------------

    At CAEP/3, the CAEP members agreed that the above amendments to the 
calibration and test gases were justified, and thus, these amendments 
were then adopted.\101\ Today, EPA will incorporate by reference the 
amendments to the criteria on calibration and test gases for the test 
procedures of gaseous emissions, because the changes improve the test 
procedures by correcting inconsistencies and distinguishing between 
calibration and test gases. The amendments will include the following: 
(1) Listing all calibration gases separately from test gases for HC, 
CO<INF>2</INF>, CO and NO<INF>X</INF> analyzers, (2) changing 
``N<INF>2</INF>'' to ``zero nitrogen'' in relation to the test gases 
for the HC and NO<INF>X</INF> analyzers, (3) adding ``CO<INF>2</INF> in 
zero nitrogen'' as a test gas for CO<INF>2</INF> analyzer, (4) changing 
``air'' to ``zero air'' in relation to the test gas for CO and 
CO<INF>2</INF> analyzers, (5) revising the accuracy to ``<plus-minus> 1 
percent'' for the ``propane in zero air''

[[Page 69682]]

test gas of HC analyzer, (6) amending the accuracy to ``<plus-minus> 1 
percent'' for the ``CO<INF>2</INF> in zero air'' test gas of 
CO<INF>2</INF> analyzer, (7) adding the accuracy ``<plus-minus> 1 
percent'' for the ``CO<INF>2</INF> in zero nitrogen'' test gas of 
CO<INF>2</INF> analyzer, (8) changing accuracy to ``<plus-minus> 1 
percent'' for test gas of CO analyzer, and (9) revising accuracy to 
``<plus-minus> 1 percent'' for test gas of NO<INF>X</INF> analyzer.
---------------------------------------------------------------------------

    \101\ ICAO/CAEP, Report of Third Meeting, Montreal, Quebec, 
December 5-15, 1995, Document 9675, CAEP/3. Copies of this document 
can be obtained from ICAO (http://www.icao.int).
---------------------------------------------------------------------------

    Manufacturers are already voluntarily complying with ICAO's 1997 
amendments to the criteria on calibration and test gases for the test 
procedures of gaseous emissions. Thus, formal adoption of these ICAO 
test procedure amendments will require no new action by manufacturers. 
In addition, the existence of ICAO's requirements will ensure that the 
costs of compliance (as well as the air quality impact) with these test 
procedures will be minimal. (In the 1982 and 1997 final rules on 
aircraft engine emissions (47 FR 58462, December 30, 1982 and 62 FR 
25356, May 8, 1997, respectively), EPA incorporated by reference the 
then-existing ICAO testing and measurement procedures for aircraft 
engine emissions (ICAO International Standards and Recommended 
Practices Environmental Protection, Annex 16, Volume II, ``Aircraft 
Engine Emissions,'' First and Second Editions, Appendices 3 and 5 were 
incorporated by reference in 40 CFR 87.64) in order to eliminate 
confusion over minor differences in procedures for demonstrating 
compliance with the U.S. and ICAO standards.)

V. Correction of Exemptions for Very Low Production Models

    Because of an editorial error, the section in the aircraft engine 
emission regulations regarding exemptions for very low production 
models is incorrectly specified (see section 40 CFR 87.7(b)(1) and 
(2)). In the October 18, 1984 final rulemaking (49 FR 41000), EPA 
intended to amend the low production engine provisions of the aircraft 
regulations by revising paragraph (b) and deleting paragraphs (b)(1) 
and (b)(2) in order to eliminate the maximum annual production limit of 
20 engines per year. In the revisions to paragraph (b), EPA retained 
the maximum total production limit of 200 units for aircraft models 
certified after January 1, 1984.\102\ For Sec.  87.7(b), today, EPA 
will correct this editorial error by eliminating paragraph (b)(1) and 
(b)(2).
---------------------------------------------------------------------------

    \102\ This action was taken in 1984 to provide greater 
flexibility to manufacturers for scheduling engine production rates 
during the final years.
---------------------------------------------------------------------------

    As discussed further in the 1984 final rulemaking, this action will 
provide more flexibility for engine manufacturers in scheduling during 
the last few engine production years. Also, the air quality impact of 
eliminating the annual production limit will be very small.

VI. Coordination With FAA

    The requirements contained in this action are being promulgated 
after consultation with the Federal Aviation Administration (FAA). 
Section 231(a)(2)(B)(i) of the CAA requires EPA to ``consult with the 
Administrator of the [FAA] on aircraft engine emission standards'' 42 
U.S.C. 7571(a)(2)(B)(i), and section 231(a)(2)(B)(ii) indicates that 
EPA ``shall not change the aircraft engine emission standards if such 
change would significantly increase noise * * *.'' 42 U.S.C. 
7571(a)(2)(B)(ii). Section 231(b) of the CAA states that ``[a]ny 
regulation prescribed under this section (and any revision thereof) 
shall take effect after such period as the Administrator finds 
necessary (after consultation with the Secretary of Transportation) to 
permit the development and application of the requisite technology, 
giving appropriate consideration to the cost of compliance within such 
period.'' 42 U.S.C. 7571(b). Section 231(c) provides that any 
regulation under section 231 ``shall not apply if disapproved by the 
President * * * on the basis of a finding by the Secretary of 
Transportation that any such regulation would create a hazard to 
aircraft safety.'' 42 U.S.C. 7571(c). Under section 232 of the CAA, the 
Department of Transportation (DOT) has the responsibility to enforce 
the aircraft emission standards established by EPA under section 
231.\103\ As in past rulemakings and pursuant to the above referenced 
sections of the CAA, EPA has coordinated with the FAA of the DOT with 
respect to today's action.
---------------------------------------------------------------------------

    \103\ The functions of the Secretary of Transportation under 
part B of title II of the Clean Air Act (Sec. Sec.  231-234, 42 
U.S.C. 7571-7574) have been delegated to the Administrator of the 
FAA. 49 CFR 1.47(g).
---------------------------------------------------------------------------

    Moreover, FAA is the official U.S. delegate to ICAO. FAA agreed to 
the 1997 and 1999 amendments at ICAO's Third and Fourth Meetings of the 
Committee on Aviation Environmental Protection (CAEP/3 and CAEP/4) 
after advisement from EPA.\104\ FAA and EPA were both members of the 
CAEP's Working Group 3 (among others), whose objective was to evaluate 
emissions technical issues and develop recommendations on such issues 
for CAEP/3 and CAEP/4. After assessing emissions test procedure 
amendments and new NO<INF>X</INF> standards, Working Group 3 made 
recommendations to CAEP on these elements. These recommendations were 
then considered at the CAEP/3 and CAEP/4 meetings, respectively, prior 
to their adoption by ICAO in 1997 and 1999.
---------------------------------------------------------------------------

    \104\ The Third Meeting of CAEP (CAEP/3) occurred in Montreal, 
Quebec from December 5 through 15 in 1995. CAEP/4 took place in 
Montreal from April 6 through 8, 1998.
---------------------------------------------------------------------------

    In addition, as discussed above, FAA will have the responsibility 
to enforce today's requirements. As a part of its compliance 
responsibilities, FAA conducts the emission tests or delegates that 
responsibility to the engine manufacturer, which is then monitored by 
the FAA. Since the FAA does not have the resources or the funding to 
test engines, FAA selects engineers at each plant to serve as 
representatives (called designated engineering representatives (DERs)) 
for the FAA while the manufacturer performs the test procedures. DERs' 
responsibilities include evaluating the test plan, the test engine, the 
test equipment, and the final testing report sent to FAA. DERs' 
responsibilities are determined by the FAA and today's rulemaking will 
not affect their duties.

VII. Possible Future Aviation Emission Reductions (EPA/FAA Voluntary 
Aviation Emissions Reduction Initiative)

    As discussed in the proposal, there is growing interest, 
particularly at the state and local level, in addressing emissions from 
aircraft and other aviation-related sources. Such interest is often 
related to plans for airport expansion which is occurring across the 
country. It is possible that other approaches may provide effective 
avenues to achieve additional aviation emission reductions, beyond EPA 
establishing aircraft engine emission standards.
    Concerns by state and local air agencies and environmental and 
public health organizations about aviation emissions, led to EPA and 
FAA signing a memorandum of understanding (MOU) in March 1998 agreeing 
to work to identify efforts that could reduce aviation emissions.\105\ 
FAA and EPA participated in a national stakeholder initiative led by 
states and industry whose goal was to develop a voluntary program to 
reduce pollutants from aircraft and other aviation sources that

[[Page 69683]]

contribute to local and regional air pollution in the United States. 
The major stakeholders that participated in this initiative included 
representatives of the aviation industry (passenger and cargo airlines 
and engine manufacturers), airports, state and local air pollution 
control officials, environmental organizations, and NASA.
---------------------------------------------------------------------------

    \105\ FAA and EPA, ``Agreement Between Federal Aviation 
Administration and Environmental Protection Agency Regarding 
Environmental Matters Relation to Aviation,'' signed on March 24, 
1998 by FAA's Acting Assistant Administrator for Policy, Planning, 
and International Aviation, Louise Maillet, and EPA's Acting 
Assistant Administrator for Air and Radiation, Richard Wilson. A 
copy of this document can be found in Docket OAR-2002-0030.
---------------------------------------------------------------------------

    Initially, the discussions with stakeholders focused on the 
prospect of aircraft engine emission reduction retrofit kits, which 
might be applied to certain existing aircraft engines.\106\ However, as 
the initiative evolved, the focus was expanded by the stakeholders to 
identify strategies for various types of ground service equipment (GSE) 
in use at airports,\107\ in addition to strategies to reduce aircraft 
emissions.\108\ (At the same time, FAA developed a program, with 
Congressional approval, to fund conversion of airport infrastructure 
and ground support vehicles to alternative fuels technologies.\109\) 
Unfortunately, the state and industry stakeholders did not reach 
consensus on a national aviation emissions reduction program. The 
Agencies are currently contemplating next steps following from the 
national stakeholder initiative and discussions of potential voluntary 
programs.
---------------------------------------------------------------------------

    \106\ Two engine models were indeed certificated with emissions 
retrofit kits, and a number of these engines have been purchased for 
aircraft with the retrofit kits installed in their stock 
configuration. However, retrofit kits have not to date provided 
widescale emissions improvements because it seems they may have 
limited applicability to certain engine types, small emission 
benefits, and cost issues.
    \107\ The stakeholders considered the impact, operation and 
design of GSE at airports, and whether to undertake projects at 
several airports to reduce overall emissions.
    \108\ Operational strategies, such as reducing the time in which 
aircraft are in idle and taxi modes and the impact of auxiliary 
power units (APUs) were also considered.
    \109\ The Vision 100-Century of Aviation Reauthorization Act, 
signed into law on December 12, 2003 (Pub. L. 108-176), directs the 
FAA to establish a national program to reduce airport ground 
emissions at commercial service airports located in air quality 
nonattainment and maintenance areas. The new Voluntary Airport Low 
Emissions (VALE) program will allow airport sponsors to use the 
Airport Improvement Program (AIP) and Passenger Facility Charges 
(PFCs) to finance low-emission vehicles, refueling and recharging 
stations, gate electrification, and other airport air quality 
improvements. See the FAA website located at http://www.faa.gov/arp/environmental/vale.
---------------------------------------------------------------------------

    In addition, in the proposal EPA invited comment on the national 
stakeholder initiative and any other approaches for aviation emission 
reductions, and we received many suggestions from commenters. We may 
consider these suggested approaches during our current reflection on 
the stakeholder initiative and for future voluntary programs.
    Finally, FAA has two other initiatives that will assist in 
addressing concerns with respect to emissions from aircraft. First, in 
September 2003 it created a Center of Excellence--Partnership for 
Reduction of Air Transportation Noise and Emissions Reduction 
(PARTNER)--a consortium of 8 universities, 29 industry representatives 
as well as NASA and Transport Canada-to develop new approaches and 
solutions to reduce aviation's environmental impacts. Second, with the 
assistance of the National Academy of Sciences, FAA is developing the 
next generation of aviation noise and emissions models and analytical 
tools improve measurement, understanding, and targeted solutions. See 
the Summary and Analysis of Comments for further discussion of 
approaches to additional aviation emission reductions.

VIII. Regulatory Impacts

    Aircraft engines are international commodities, and thus, they are 
designed to meet international standards. Today's action will have the 
benefit of establishing consistency between U.S. and international 
emission standards and test procedures. Thus, an emission certification 
test which meets U.S. requirements will also be applicable to all ICAO 
requirements. Engine manufacturers are already developing improved 
technology in response to the ICAO standards that match standards 
promulgated here, and EPA does not believe that the costs incurred by 
the aircraft industry as a result of the existing ICAO standards should 
be attributed to today's regulations. Also, the test procedure 
amendments (revisions to criteria on calibration and test gases) 
necessary to determine compliance are already being adhered to by 
manufacturers during current engine certification tests. Therefore, EPA 
believes that today's regulations will impose no additional burden on 
manufacturers.
    The existence of ICAO's requirements results in minimal cost as 
well as air quality benefits from today's requirements.\110\ Since 
aircraft and aircraft engines are international commodities, there is 
commercial benefit to consistency between U.S. and international 
emission standards and control program requirements. Also, the adoption 
of the ICAO standards and related test procedures is consistent with 
our treaty obligations.
---------------------------------------------------------------------------

    \110\ CAEP's Forecasting and Economic Analysis Support Group 
(FESG) concluded at CAEP/4 that their assessment of these new 
NO<INF>X</INF> standards indicates that the direct costs of the 
standards would be minimal, and the benefits would be modest. (ICAO, 
CAEP/4, Working Paper 4, ``Economic Assessment of the EPG 
NO<INF>X</INF> Stringency Proposal,'' March 12, 1998, Presented by 
the Chairman of FESG, Agenda Item 1: Review of proposals relating to 
NO<INF>X</INF> emissions, including the amendment of Annex 16, 
Volume II. A copy of this paper can be found in Docket OAR-2002-
0030.
---------------------------------------------------------------------------

IX. Public Participation

    A number of interested parties participated in the rulemaking 
process that culminates with this final rule. This process provided 
opportunity for submitting written public comments following the 
proposal that we published on September 30, 2003 (68 FR 56226). We 
considered these comments in developing the final rule. In addition, we 
held a public hearing on the proposed rulemaking on November 13, 2003, 
and we have considered comments presented at the hearing.
    We have prepared a detailed Summary and Analysis of Comments 
document, which describes comments we received on the proposal and our 
response to each of these comments. The Summary and Analysis of 
Comments is available in the e-docket for this rule, as well as on the 
Office of Transportation and Air Quality homepage (http://www.epa.gov/otaq/aviation.htm). In addition, comments and responses for key issues 
are included throughout this preamble.

X. Statutory Provisions and Legal Authority

    The statutory authority for today's proposal is provided by 
sections 231 and 301(a) of the Clean Air Act, as amended, 42 U.S.C. 
7571 and 7601(a). See section II of today's rule for discussion of how 
EPA meets the CAA's statutory requirements.

XI. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review

    Under Executive Order 12866 (58 FR 51735, October 4, 1993), the 
Agency must determine whether this regulatory action is ``significant'' 
and therefore subject to Office of Management and Budget (OMB) review 
and the requirements of the Executive Order. The Order defines 
``significant regulatory action'' as one that is likely to result in a 
rule that may:
    (1) Have an annual effect on the economy of $100 million or more or 
adversely affect in a material way the economy, a sector of the 
economy, productivity, competition, jobs, the environment, public 
health or safety, or State, local, or tribal governments or 
communities;

[[Page 69684]]

    (2) Create a serious inconsistency or otherwise interfere with an 
action taken or planned by another agency;
    (3) Materially alter the budgetary impact of entitlements, grants, 
user fees, or loan programs or the rights and obligations of recipients 
thereof; or
    (4) Raise novel legal or policy issues arising out of legal 
mandates, the President's priorities, or the principles set forth in 
the Executive Order.
    Pursuant to the terms of Executive Order 12866, OMB has notified 
EPA that it considers this a ``significant regulatory action'' within 
the meaning of the Executive Order. EPA has submitted this action to 
OMB for review. Changes made in response to OMB suggestions or 
recommendations will be documented in the public record.

B. Paperwork Reduction Act

    This action does not impose an information collection burden under 
the provisions of the Paperwork Reduction Act, 44 U.S.C. 3501 et seq. 
Any reporting and recordkeeping requirements associated with these 
standards would be defined by the Secretary of Transportation in 
enforcement regulations issued later under the provisions of section 
232 of the Clean Air Act. Since most if not all manufacturers already 
measure NO<INF>X</INF> and report the results to the FAA, any 
additional reporting and record keeping requirements associated with 
FAA enforcement of today's regulations would likely be very small.
    Burden means the total time, effort, or financial resources 
expended by persons to generate, maintain, retain, or disclose or 
provide information to or for a Federal agency. This includes the time 
needed to review instructions; develop, acquire, install, and utilize 
technology and systems for the purposes of collecting, validating, and 
verifying information, processing and maintaining information, and 
disclosing and providing information; adjust the existing ways to 
comply with any previously applicable instructions and requirements; 
train personnel to be able to respond to a collection of information; 
search data sources; complete and review the collection of information; 
and transmit or otherwise disclose the information.
    An agency may not conduct or sponsor, and a person is not required 
to respond to a collection of information unless it displays a 
currently valid OMB control number. The OMB control numbers for EPA's 
regulations in 40 CFR are listed in 40 CFR part 9.

C. Regulatory Flexibility Analysis

    EPA has determined that it is not necessary to prepare a regulatory 
flexibility analysis in connection with this final rule.
    For purposes of assessing the impacts of today's rule on small 
entities, small entity is defined as: (1) A small business as defined 
by SBA size standards; (2) a small governmental jurisdiction that is a 
government of a city, county, town, school district or special district 
with a population of less than 50,000; or (3) a small organization that 
is any not-for-profit enterprise which is independently owned and 
operated and is not dominant in its field. The following Table XI-C-1 
provides an overview of the primary SBA small business categories 
potentially affected by this regulation.

    Table XI-C-1.--Primary SBA Small Business Categories Potentially
                       Affected by This Regulation
------------------------------------------------------------------------
                                       NAICS a     Defined by SBA as a
              Industry                  codes      small business if: b
------------------------------------------------------------------------
Manufacturers of new aircraft            336412  < 1,000 employees.
 engines.
Manufacturers of new aircraft.......     336411  < 1,500 employees.
------------------------------------------------------------------------
a North American Industry Classification System (NAICS).
b According to SBA's regulations (13 CFR part 121), businesses with no
  more than the listed number of employees or dollars in annual receipts
  are considered ``small entities'' for purposes of a regulatory
  flexibility analysis.

    After considering the economic impacts of today's rule on small 
entities, EPA has concluded that this action will not have a 
significant economic impact on a substantial number of small entities. 
This rule will not impose any requirements on small entities. Our 
review of the list of manufacturers of commercial aircraft gas turbine 
engines with rated thrust greater than 26.7 kN and manufacturers of 
aircraft with such engines indicates that there are no U.S. 
manufacturers that qualify as small businesses. We are unaware of any 
foreign manufacturers with a U.S.-based facility that will qualify as a 
small business.
    As discussed earlier, today's action will codify emission standards 
that manufacturers currently adhere to (nearly all in-production 
engines already meet the standards). These standards are equivalent to 
the ICAO international consensus standards. Today's emission standards 
will not impose any additional burden on manufacturers because they are 
already designing engines to meet the ICAO standards. Also, the test 
procedure amendments (revisions to criteria on calibration and test 
gases) necessary to determine compliance are already being adhered to 
by manufacturers during current engine certification tests.

D. Unfunded Mandates Reform Act

    Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), Public 
Law 104-4, establishes requirements for Federal agencies to assess the 
effects of their regulatory actions on State, local, and tribal 
governments and the private sector. Under section 202 of the UMRA, EPA 
generally must prepare a written statement, including a cost-benefit 
analysis, for proposed and final rules with ``Federal mandates'' that 
may result in expenditures to State, local, and tribal governments, in 
the aggregate, or to the private sector, of $100 million or more in any 
one year. Before promulgating an EPA rule for which a written statement 
is needed, section 205 of the UMRA generally requires EPA to identify 
and consider a reasonable number of regulatory alternatives and adopt 
the least costly, most cost-effective or least burdensome alternative 
that achieves the objectives of the rule. The provisions of section 205 
do not apply when they are inconsistent with applicable law. Moreover, 
section 205 allows EPA to adopt an alternative other than the least 
costly, most cost-effective or least burdensome alternative if the 
Administrator publishes with the final rule an explanation why that 
alternative was not adopted. Before EPA establishes any regulatory 
requirements that may significantly or uniquely affect small 
governments, including tribal governments, it must have developed under 
section 203 of the UMRA a small government agency plan. The plan must 
provide for notifying potentially affected small governments, enabling 
officials of affected small governments to have meaningful and timely 
input in the development of EPA regulatory

[[Page 69685]]

proposals with significant Federal intergovernmental mandates, and 
informing, educating, and advising small governments on compliance with 
the regulatory requirements.
    EPA has determined that this rule does not contain a Federal 
mandate that may result in expenditure of $100 million or more for 
State, local, or tribal governments, in the aggregate or the private 
sector in any one year. This rule contains no regulatory requirements 
that might significantly or uniquely affect small governments. Today's 
action will codify emission standards that manufacturers currently 
adhere to (nearly all in-production engines already meet the 
standards). These standards are equivalent to the ICAO international 
consensus standards. Today's emission standards will not impose any 
additional burden on manufacturers because they are already designing 
new engines to meet the ICAO standards. Thus, the annual effect on the 
economy of today's standards will be minimal. Today's rule is not 
subject to the requirements of sections 202 and 205 of the UMRA.

E. Executive Order 13132: Federalism

    Executive Order 13132, entitled ``Federalism'' (64 FR 43255, August 
10, 1999), requires EPA to develop an accountable process to ensure 
``meaningful and timely input by State and local officials in the 
development of regulatory policies that have federalism implications.'' 
``Policies that have federalism implications'' is defined in the 
Executive Order to include regulations that have ``substantial direct 
effects 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.''
    Today's rule does not have federalism implications. It will not 
have substantial direct effects 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, 
as specified in Executive Order 13132. As discussed earlier, section 
233 of the CAA preempts states from adopting or enforcing aircraft 
engine emission standards that are not identical to our standards. This 
rule merely modifies existing EPA aircraft engine emission standards 
and test procedures and therefore will merely continue an existing 
preemption of State and local law. Thus, Executive Order 13132 does not 
apply to this rule.
    In the spirit of Executive Order 13132, and consistent with EPA 
policy to promote communications between EPA and State and local 
governments, EPA specifically solicited comment on the proposed rule 
from State and local officials.

F. Executive Order 13175: Consultation and Coordination With Indian 
Tribal Governments

    Executive Order 13175, entitled ``Consultation and Coordination 
with Indian Tribal Governments'' (65 FR 67249, November 6, 2000), 
requires EPA to develop an accountable process to ensure ``meaningful 
and timely input by tribal officials in the development of regulatory 
policies that have tribal implications.''
    This rule does not have tribal implications, as specified in 
Executive Order 13175. The promulgated emission standards and other 
related requirements for private industry in this rule have national 
applicability and therefore do not uniquely affect the communities of 
Indian Tribal Governments. As discussed earlier, section 233 of the CAA 
preempts states from adopting or enforcing aircraft engine emission 
standards that are not identical to our standards. This final rule 
merely modifies existing EPA aircraft engine emission standards and 
test procedures and therefore will merely continue an existing 
preemption of State and local law. In addition, today's rule will be 
implemented at the Federal level and impose compliance obligations only 
on engine manufacturers. Thus, Executive Order 13175 does not apply to 
this rule.

G. Executive Order 13045: Protection of Children From Environmental 
Health & Safety Risks

    Executive Order 13045, ``Protection of Children from Environmental 
Health Risks and Safety Risks'' (62 FR 19885, April 23, 1997) applies 
to any rule that (1) is determined to be ``economically significant'' 
as defined under Executive Order 12866, and (2) concerns an 
environmental health or safety risk that EPA has reason to believe may 
have a disproportionate effect on children. If the regulatory action 
meets both criteria, Section 5-501 of the Order directs the Agency to 
evaluate the environmental health or safety effects of the planned rule 
on children, and explain why the planned regulation is preferable to 
other potentially effective and reasonably feasible alternatives 
considered by the Agency.
    This rule is not subject to Executive Order 13045 because the 
Agency does not have reason to believe the environmental health risks 
or safety risks addressed by this action present a disproportionate 
risk to children. EPA believes that the NO<INF>X</INF> emission 
reductions (NO<INF>X</INF> is a precursor to the formation of ozone and 
PM) from this rulemaking will further improve air quality and will 
further improve children's health.

H. Executive Order 13211: Actions That Significantly Affect Energy 
Supply, Distribution, or Use

    This rule is not a ``significant energy action'' as defined in 
Executive Order 13211, ``Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use'' (66 FR 28355 
(May 22, 2001)) because it is not likely to have a significant adverse 
effect on the supply, distribution, or use of energy. As discussed 
earlier, today's action will codify emission standards that 
manufacturers currently adhere to (nearly all in-production engines 
already meet the standards). These standards are equivalent to the ICAO 
international consensus standards. The final standards will have no 
likely adverse energy effects because manufacturers are already 
designing engines to meet the ICAO standards. Also, the test procedure 
amendments (revisions to criteria on calibration and test gases) 
necessary to determine compliance are already being adhered to by 
manufacturers during current engine certification tests. Thus, we have 
concluded that this rule is not likely to have any adverse energy 
effects.

I. National Technology Transfer Advancement Act

    Section 12(d) of the National Technology Transfer and Advancement 
Act of 1995 (``NTTAA''), Public Law 104-113, section 12(d) (15 U.S.C. 
272 note) directs EPA to use voluntary consensus standards in its 
regulatory activities unless to do so would be inconsistent with 
applicable law or otherwise impractical. Voluntary consensus standards 
are technical standards (e.g., materials specifications, test methods, 
sampling procedures, and business practices) that are developed or 
adopted by voluntary consensus standards bodies. NTTAA directs EPA to 
provide Congress, through OMB, explanations when the Agency decides not 
to use available and applicable voluntary consensus standards.
    This final rulemaking involves technical standards for testing 
emissions for commercial aircraft gas turbine engines. EPA will use 
test procedures contained in ICAO International Standards and 
Recommended Practices Environmental Protection, with the modifications 
contained in this

[[Page 69686]]

rulemaking.\111\ These procedures are currently used by all 
manufacturers of commercial aircraft gas turbine engines (with thrust 
greater than 26.7 kN) to demonstrate compliance with ICAO emissions 
standards.
---------------------------------------------------------------------------

    \111\ ICAO International Standards and Recommended Practices 
Environmental Protection, Annex 16, Volume II, ``Aircraft Engine 
Emissions,'' Second Edition, July 1993--Amendment 3, March 20, 1997. 
Copies of this document can be obtained from ICAO (http://www.icao.int).
---------------------------------------------------------------------------

J. Congressional Review Act

    The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the 
Small Business Regulatory Enforcement Fairness Act of 1996, generally 
provides that before a rule may take effect, the agency promulgating 
the rule must submit a rule report, which includes a copy of the rule, 
to each House of the Congress and to the Comptroller General of the 
United States. EPA will submit a report containing this rule and other 
required information to the U.S. Senate, the U.S. House of 
Representatives, and the Comptroller General of the United States prior 
to publication of the rule in the Federal Register. A major rule cannot 
take effect until 60 days after it is published in the Federal 
Register. This action is not a ``major rule'' as defined by 5 U.S.C. 
804(2). This rule will be effective December 19, 2005.

List of Subjects in 40 CFR Part 87

    Environmental protection, Air pollution control, Aircraft, 
Incorporation by reference.

    Dated: November 9, 2005.
Stephen L. Johnson,
Administrator.

0
For the reasons set out in the preamble, title 40, chapter I of the 
Code of Federal Regulations is amended as follows:

PART 87--CONTROL OF AIR POLLUTION FROM AIRCRAFT AND AIRCRAFT 
ENGINES

0
1. The authority citation for part 87 continues to read as follows:

    Authority: Secs. 231, 301(a), Clean Air Act, as amended (42 
U.S.C 7571, 7601(a)).

Subpart A--[Amended]

0
2. Section 87.7 is amended by removing paragraphs (b)(1) and (b)(2).

0
3. A new Sec.  87.8 is added to read as follows:


Sec.  87.8  Incorporation by reference.

    We have incorporated by reference the documents listed in this 
section. The Director of the Federal Register approved the 
incorporation by reference as prescribed in 5 U.S.C. 552(a) and 1 CFR 
part 51. Anyone may inspect copies at the U.S. EPA, Air and Radiation 
Docket and Information Center, 1301 Constitution Ave., NW., Room B102, 
EPA West Building, Washington, DC 20460 or at the National Archives and 
Records Administration (NARA). For information on the availability of 
this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.
    (a) ICAO material. Table 1 of Sec.  87.8 lists material from the 
International Civil Aviation Organization that we have incorporated by 
reference. The first column lists the number and name of the material. 
The second column lists the sections of this part where we reference 
it. Anyone may purchase copies of these materials from the 
International Civil Aviation Organization, Document Sales Unit, 999 
University Street, Montreal, Quebec, Canada H3C 5H7. Table 1 follows:

                 Table 1 of Sec.   87.8.--ICAO Materials
------------------------------------------------------------------------
          Document number and name                Part 87 reference
------------------------------------------------------------------------
International Civil Aviation Organization    87.8, 87.64, 87.71, 87.82,
 Annex 16, Environmental Protection, Volume   87.89.
 II, Aircraft Engine Emissions, Second
 Edition, July 1993, Including Amendment 3
 of March 20, 1997 (as indicated in
 footnoted pages.).
------------------------------------------------------------------------

    (b) [Reserved]

Subpart C--[Amended]

0
4. Section 87.21 is amended by adding paragraphs (d)(1)(vi) and 
(d)(1)(vii) to read as follows:


Sec.  87.21  Standards for exhaust emissions.

* * * * *
    (d) * * *
    (1) * * *
    (vi) Engines of a type or model of which the date of manufacture of 
the first individual production model was after December 31, 2003:
    (A) Engines with a rated pressure ratio of 30 or less:
    (1) Engines with a maximum rated output greater than 89 
kilonewtons:
    Oxides of Nitrogen: (19 + 1.6(rPR)) grams/kilonewtons rO.
    (2) Engines with a maximum rated output greater than 26.7 
kilonewtons but not greater than 89 kilonewtons:
    Oxides of Nitrogen: (37.572 + 1.6(rPR) - 0.2087(rO)) grams/
kilonewtons rO.
    (B) Engines with a rated pressure ratio greater than 30 but less 
than 62.5:
    (1) Engines with a maximum rated output greater than 89 
kilonewtons:
    Oxides of Nitrogen: (7 + 2(rPR)) grams/kilonewtons rO.
    (2) Engines with a maximum rated output greater than 26.7 
kilonewtons but not greater than 89 kilonewtons:
    Oxides of Nitrogen: (42.71 + 1.4286(rPR) - 0.4013(rO) + 0.00642(rPR 
x rO)) grams/kilonewtons rO.
    (C) Engines with a rated pressure ratio of 62.5 or more:
    Oxides of Nitrogen: (32 + 1.6(rPR)) grams/kilonewtons rO.
    (vii) The emission standards prescribed in paragraph (d)(1)(vi) of 
this section shall apply as prescribed beginning December 19, 2005.
* * * * *

Subpart G--[Amended]

0
5. Section 87.64 is revised to read as follows:


Sec.  87.64  Sampling and analytical procedures for measuring gaseous 
exhaust emissions.

    The system and procedures for sampling and measurement of gaseous 
emissions shall be as specified by Appendices 3 and 5 to ICAO Annex 16 
(incorporated by reference in Sec.  87.8).

0
6. Section 87.71 is revised to read as follows:


Sec.  87.71  Compliance with gaseous emission standards.

    Compliance with each gaseous emission standard by an aircraft 
engine shall be determined by comparing the pollutant level in grams/
kilonewton/thrust/cycle or grams/kilowatt/cycle as calculated in Sec.  
87.64 with the applicable emission standard under this part. An 
acceptable alternative to testing every

[[Page 69687]]

engine is described in Appendix 6 to ICAO Annex 16 (incorporated by 
reference in Sec.  87.8). Other methods of demonstrating compliance may 
be approved by the Secretary with the concurrence of the Administrator.

Subpart H--[Amended]

0
7. Section 87.82 is revised to read as follows:


Sec.  87.82  Sampling and analytical procedures for measuring smoke 
exhaust emissions.

    The system and procedures for sampling and measurement of smoke 
emissions shall be as specified by Appendix 2 to ICAO Annex 16 
(incorporated by reference in Sec.  87.8).

0
8. Section 87.89 is revised to read as follows:


Sec.  87.89  Compliance with smoke emission standards.

    Compliance with each smoke emission standard shall be determined by 
comparing the plot of SN as a function of power setting with the 
applicable emission standard under this part. The SN at every power 
setting must be such that there is a high degree of confidence that the 
standard will not be exceeded by any engine of the model being tested. 
An acceptable alternative to testing every engine is described in 
Appendix 6 to ICAO Annex 16 (incorporated by reference in Sec.  87.8).

[FR Doc. 05-22704 Filed 11-16-05; 8:45 am]
BILLING CODE 6560-50-U


</pre><script data-cfasync="false" src="/cdn-cgi/scripts/5c5dd728/cloudflare-static/email-decode.min.js"></script></body>
</html>