With the recent finalization of the finding that greenhouse gas emissions from certain classes of aircraft engines endanger public health and welfare, the EPA must promulgate aircraft engine emission standards under Clean Air Act ("CAA") Section 231. The endangerment finding applies to subsonic jet aircraft with a maximum takeoff mass greater than 5,700 kilograms and subsonic propeller-driven (e.g., turboprop) aircraft with a maximum takeoff mass greater than 8,618 kilograms, which are "covered aircraft." The finding does not include smaller turboprops, smaller jet aircraft, piston-engine aircraft, helicopters, or military aircraft. Examples of covered aircraft include smaller jet aircraft such as the Cessna Citation CJ3+ and the Embraer E170, up to and including the largest commercial jet aircraft—the Airbus A380 and the Boeing 747 as well as larger turboprop aircraft, such as the ATR 72 and the Bombardier Q400.
As a member to the Convention on International Civil Aviation ("Chicago Convention"), the United States is obligated under treaty to adopt domestic law generally in accord with the standard-setting and recommendations of the International Civil Aviation Organization ("ICAO"). In the past, when ICAO has adopted emission standards, EPA has subsequently initiated rulemaking under CAA Section 231 to establish domestic standards at least as stringent as the ICAO standards. In 2007, the U.S. Appeals Court for the D.C. Circuit affirmed this practice as a "reasonable interpretation" of the agency's obligations under Section 231.
In 2010, ICAO began the process of developing an emission standard for carbon dioxide. ICAO's new carbon dioxide emission standards will likely apply to new aircraft type designs as of 2020 and new deliveries of current in-production aircraft types from 2023. According to the White House, the standards are expected to reduce carbon emissions more than 650 million tons between 2020 and 2040, equivalent to removing over 140 million cars from the road for a year. In October 2016, the ICAO Assembly is expected approve these new carbon dioxide emission standards to be formally adopted in March 2017. If these final standards are adopted, the U.S. emission standards promulgated by EPA will need to be at least as stringent as the ICAO standard.
Regardless of the status of the ICAO carbon dioxide emission standards, EPA now has an independent obligation under the endangerment finding to set emission standards for greenhouse gases from the covered classes of aircraft engines. Entities that manufacture and sell aircraft engines and aircraft in the United States can expect future regulatory action to curb greenhouse gas emissions.
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