The Environmental Protection Agency yesterday stepped toward regulating aircraft greenhouse gas (GHG) emissions, proposing to find that emissions from certain types of aircraft contribute to air pollution that endangers public health and welfare. 

The release of the proposed finding, detailed in an advance notice of proposed rulemaking (ANPRM), would compel the agency to regulate aircraft GHG emissions under the Clean Air Act. The proposal has been widely anticipated by industry since it also clears the way for the EPA to work in tandem with the International Civil Aviation Organization on the CO₂ standard. ICAO is expected to establish a standard in February next year that will cover new and possibly in-production aircraft.

The finding would cover jet aircraft with a maximum takeoff mass (mtom) of 5,700 kilograms (12,566 pounds) or more and propeller-driven aircraft with a mtom of greater than 8,618 kilograms. In the ANPRM, the EPA also seeks comment on whether smaller aircraft should be included in an endangerment finding.

The EPA estimates that the “covered” aircraft account for 3 percent of total U.S. GHG emissions and “comprise the single largest transportation source in the U.S. that has not yet been regulated for GHG emissions.” The EPA also expresses concern about estimates that aircraft GHG emissions could grow by as much as 50 percent over then next couple of decades. "Newer generation aircraft and engines are more efficient," noted Matthew DeWitt, a distinguished research engineer at the University of Dayton Research Institute's Von Ohain Fuels and Combustion Center. "But there's a continued increase in the demand for global aviation and that's leading to a potential total increase in the net greenhouse gas emissions even though they are becoming more efficient."

The agency notes that it has received from several environmental groups a citizen petition to issue such a finding. 

The ANPRM sets the stage “for a possible subsequent domestic rulemaking process to adopt standards that are of at least equivalent stringency as the anticipated ICAO CO₂ standards,” the agency said, noting that states would be required to adopt standards that are at least as stringent as the standard established by ICAO. 

“The EPA has worked diligently over the past four years within the ICAO/CAEP process on a range of technical issues regarding aircraft CO₂ emission standards,” the agency said.

The ANPRM does not propose regulatory requirements, but seeks public input on emissions standards. Since it is focused on aircraft engine emission standards, it does not delve into operational requirements nor does it address possible market-based measures that have been so controversial among operators.

Noting such standards “are still in the early stages of development,” the EPA said public input would be helpful.

Along with aircraft size, the agency questions whether the standards should apply to aircraft already in production or only new aircraft types.

An ICAO working group accepted the U.S. recommendation that the purpose of the international CO₂ emissions standard should be “to achieve CO₂ emissions reductions from the aviation sector beyond expected ‘business as usual.'” The EPA seeks comment not only on that purpose, but also on how to achieve it.

The EPA is also seeking input on establishing a time frame for implementation of the standard, should it apply to in-production aircraft, since such requirements could necessitate redesign and/or recertification

The ANPRM comes as the aviation industry has appealed to U.S. regulators to work with ICAO on a uniform standard, rather than establishing separate requirements.

“Aviation is the most global of all industries, and it is important that aviation environmental standards be set by ICAO,” said GAMA president and CEO Pete Bunce. “The EPA’s draft finding recognizes this, and we agree with the agency’s commitment to the ICAO process to finalize a CO2 standard that is environmentally beneficial and that allows aviation to grow in a sustainable manner.”

NBAA president and CEO Ed Bolen added, “The aviation community has long been committed to pursuing effective and workable efforts to lower the industry's carbon footprint.Over the past several decades the industry has enormously improved fuel efficiency, and continues to do so, through the development of new technologies, the promotion of flight procedures that reduce emissions and ongoing research and testing of alternate fuels." Bolen also stressed that NBAA "will make these points very clearly in our comments to the EPA.”

Environmental groups, however, are urging the EPA to take its own action, rather than wait for ICAO. “We commend the EPA for completing this important first step in regulating carbon pollution from airplanes, but unfortunately, given the magnitude of the contribution of aircraft to climate change, the tentative approach that the EPA is considering is not up to the task,” said Earthjustice attorney Sarah Burt. “Instead of using its Clean Air Act authority to reduce these harmful emissions, the EPA proposes to follow the lead of the International Civil Aviation Organization and set a ‘business-as-usual’ standard that will lock in emissions increases for decades to come. We strongly urge the EPA to reconsider and to fulfill its Clean Air Act obligations by proposing a rule that accomplishes meaningful reductions in pollution from aircraft.”

"As long as a fossil fuel or a hydrocarbon-based fuel is used for turbine engine aircraft, which will be for the foreseeable future, the only way to decrease the total CO2 emissions is to decrease the overall fuel usage," DeWitt old AIN. "Hence an increase in fuel economy." Among the currently viable options he indicated, were improvements in aircraft engine efficiency, modifications in the airframes themselves through the use of structures such as winglets or the use of lightweight materials like composites in their construction, and the increaed production and adoption of biofuel blends. "Right now its not making much of a dent just because there hasn't been a sufficient increase in production capacity as of yet," DeWitt said. "As these blending feedstocks are being certified and approved for use, it then sets targets that refiners or producers can attempt to produce these types of alternative fuels at sufficient quantity to make an impact."