Faced with the prospect of a new regulation governing aircraft engine emissions in the U.S., aerospace manufacturers said they are already committed to reducing the industry’s environmental impact through the International Civil Aviation Organization (ICAO). Benchmarks the industry agreed to earlier this year demonstrate that commitment, said the Aerospace Industries Association (AIA), offering the U.S. industry perspective.

On July 25, the U.S. Environmental Protection Agency (EPA) issued a final determination that greenhouse gas emissions (GHGs) from aircraft engines contribute to the pollution that causes climate change and endangers public health. The agency’s “contribution” and “endangerment” findings under the Clean Air Act trigger a federal rulemaking process to set standards for aircraft engine GHG emissions.

Aircraft remain the single-largest GHG-emitting transportation source not yet subject to federal regulation, according to the EPA, which has already set GHG emissions standards for cars and trucks. U.S. aircraft flying domestic routes and international flights originating in the U.S. account for 12 percent of the transportation sector’s GHG emissions and 3 percent of total U.S. emissions, the agency reports.

“Addressing pollution from aircraft is an important element of U.S. efforts to address climate change,” stated Janet McCabe, EPA acting assistant administrator for air and radiation. “Aircraft are the third largest contributor to GHG emissions in the U.S. transportation sector, and these emissions are expected to increase in the future.”

The EPA findings relate to carbon dioxide (CO₂), methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons and sulfur hexafluoride, all of which contribute to GHG pollution, the EPA said. “These particular GHGs come primarily from engines used on large commercial jets,” the agency added.  

Covered aircraft under the EPA’s contribution finding are jets with a maximum takeoff mass greater than 5,700 kilograms (12,566 pounds) and turboprops with MTOM greater than 8,618 kilograms (19,000 pounds)—a range covering business jets to the largest commercial airliners and larger turboprops such as the ATR72 and Bombardier Q400.

In February, ICAO’s Committee on Aviation Environmental Protection (CAEP) agreed on international standards for aircraft CO₂ emissions. The standards will be presented to the ICAO Assembly for approval in October; the organization plans to formally adopt them next March. The EPA said that it “anticipates moving forward on standards that would be at least as stringent as ICAO’s standards.”

In response to the agency’s announcement, the AIA said it favors ICAO as the forum to enact emissions standards. “AIA believes the U.S. government and industry stakeholders should continue to work together under the International Civil Aviation Organization to make regulations that work globally,” said the association, which represents major U.S. aerospace companies.

“In regards to climate change, AIA hopes and anticipates the aggressive CO₂ goals our industry set—1.5 percent annual fleet fuel efficiency improvement, carbon neutral growth from 2020, halving CO₂ emissions by 2050 relative to 2005—along with further technology improvements and the stringent regulations recently agreed to by the Committee on Aviation Environmental Protection will illustrate how committed our members are to protecting our environment.”

Among manufacturers of large-aircraft engines, Pratt & Whitney referred AIN to the industry association, while GE Aviation did not immediately respond when asked for comment. Rolls-Royce also noted the CO₂ benchmarks recommended by the CAEP body of experts.

“Like many companies in the aerospace industry, Rolls-Royce encourages policies that are modeled after global airline emissions standards that were created by the International Civil Aviation Organization,” the manufacturer said. “We believe the entire industry has a role to play in reducing emissions through innovation and applied research in both products and processes. Fuel-efficient engines play an important part, but so too must advances in airframe technology and improved air traffic management and operations.”