EPA Proposed NOx Emission
Standards for Aircraft Gas Turbine
Engines
The U.S. Environmental Protection Agency (EPA) is publishing
a proposed rulemaking to adopt the NOx emission standards
approved by the United Nation's International Civil Aviation
Organization (ICAO).
Overview
EPA is proposing to adopt emission standards and related provisions for aircraft gas
turbine engines with rated thrusts greater than 26.7 kilonewtons. These engines are
used primarily on commercial passenger and freight aircraft. The proposal contains
standards and related provisions that were either previously adopted by ICAO, or
agreed on at ICAO's Committee on Aviation Environmental Protection (CAEP) in
2010. Specifically, EPA is proposing two new tiers of more stringent emission stan-
dards for oxides of nitrogen (NOx). These are referred to as the Tier 6 (or CAEP/6)
standards and the Tier 8 (or CAEP/8) standards.
The proposed standards would apply differently depending on the date the engine
model received its original airworthiness certificate as follows,
• Engine models that were originally certificated prior to the effective date of
the proposed rule may continue production without meeting the proposed
Tier 6 standards through December 31, 2012. After that date, these engines
must comply with the proposed Tier 6 standards (this date is generally referred
to as the Tier 6 production cutoff). This delay in complying with the proposed
Tier 6 standards for previously certificated engine models is intended to allow
for an orderly transition to the proposed Tier 6 standards,
• Engine models that were originally certificated between the effective date of
the proposed rule and December 31, 2013 must comply with the proposed
Tier 6 standards.
SEPA
United States
Environmental Protection
Agency
Office of Transportation and Air Quality
EPA-420-F-11-019
July 2011
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• Engine models that were originally certificated beginning on or after January 1, 2014
must comply with the proposed Tier 8 standards. EPA anticipates establishing a future
production cutoff to require all engine models that were originally certificated before
the above date to comply with the proposed Tier 8 standards. We will consider this in a
future action after first pursuing it within ICAO/CAEP,
EPA is also proposing several additional changes that would affect all aircraft gas turbine engines
that are subject to current emission requirements. First, EPA is proposing to clarify when a
design variation of a previously certified engine model causes the emission characteristics of the
new version to become different enough from its parent engine that it must conform to the most
current emissions standards. Second, EPA is proposing amendments to the emission measure'
ment procedures. These revisions are primarily intended to reflect current certification practices.
Finally, EPA is proposing to require all gas turbine and turboprop engine manufacturers to report
to EPA, emission data and other information necessary for the purpose of conducting emission
analyses and developing appropriate public policy for the aviation sector.
These proposed regulatory requirements, except a portion of the proposed engine manufacturer
reports, have already been adopted or are actively under consideration by the ICAO. The pro-
posed requirements are consistent with the United Nations Convention on International Civil
Aviation,
Public Participation Opportunities
Comments will be accepted for 60 days after the date that the proposal is published in the Federal
Register. All comments should be identified by Docket ID No. EPA-HQ-OAR-2010-0142 and
submitted by one of the following methods:
Internet: www.regulations.gov
E-mail: a-and-r-Docket@epa.gov
Mail:
Environmental Protection Agency
Mail Code 2822T
1200 Pennsylvania Avenue NW
Hand Delivery:
U.S. Environmental Protection Agency
EPA Headquarters Library
EPA West Building
Room 3334
1301 Constitution Avenue NW
Washington, DC
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For More Information
You can access the rule and related documents on EPA's Office of Transportation and Air
Quality (OTAQ) Web site at:
www.epa.gov/otaq/aviation.htm
For more information on this proposal, please contact the Assessment and Standards
Division at:
Voice-mail: (734) 214-4636
E-mail: asdinfo@epa.gov
Mail:
U.S. Environmental Protection Agency
Assessment and Standards Division
Office of Transportation and Air Quality
2000 Traverwood Drive
Ann Arbor, MI 48105
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