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The FAA has issued a final rule to limit carbon particles emitted by subsonic aircraft engines. The ruling was announced on Friday but will not be effective until May 24.
The ruling will set maximum standards for the amount of non-volatile particulate matter (nvPM) emissions from U.S. civil aircraft engines to align with EPA recommendations and International Civil Aviation Organization standards.
"This first-of-its-kind rule in the United States will reduce the environmental impact of civil aviation on our health and climate," said Laurence Wildgoose, the assistant administrator for the FAA's Office of Policy, International Affairs and Environment.
The FAA noted that ultrafine carbon particles produced by aircraft engines are an inhalation concern for humans. The nvPM emissions can become a nucleus for persistent contrails, or line-shaped clouds formed behind jet engines that can expand into broader cloudiness and may affect the planet. With the ruling, engine manufacturers will have new emissions standards to follow to reduce the harmful effects on the public's health and the environment. The ruling will give manufacturers certainty about nvPM emissions criteria which can be used in developing the next generation of aircraft engines.
The ruling was published in the Federal Register on Wednesday and will go into effect one month later, on May 24. The FAA's latest action is part of the U.S. Aviation Climate Action Plan that has launched an industry-wide effort to achieve net-zero greenhouse gas emissions by 2050. The 2021 plan notes that advancements in technology over the last 50 years have resulted in a 70 percent improvement in fuel efficiency. Most of the changes in fuel efficiency and emission levels have come from the enhancements in engine and airframe technologies and design. Continued improvements to aircraft and related technology can reduce emissions but come at a cost to manufacturers. Aircraft have long operational lives, operating for decades and determining the pace of fleet renewal. This changes the rate of investments into new technologies.
Emission reduction technologies are regulated at the engine and aircraft level as part of the airworthiness certification process. Standards are in place for CO2 and noise for planes and nitrogen oxides, nvPM mass and particle number, carbon monoxide and unburned hydrocarbons for engines. These standards ensure that new technology is incorporated into aircraft. Aircraft engines emit water vapor, gases and particulate matter into the atmosphere in addition to CO2. These can either directly or indirectly impact climate. The emissions will also interact with each other and the background atmosphere. Emissions and their impact on the environment have been studied for decades and radiatively or chemically active species like nvPM and CO have been found to potentially affect the climate.
As an industry, aviation is constantly evolving, from new technology to new equipment or materials. More sustainable options, like SAF and electric aircraft, are being developed and implemented across the globe. All-electric technology and hydrogen propulsion are being tested on small aircraft now, but implementation on larger jets or commercial aircraft is years away. The industry goal is still more than 25 years away, giving agencies like the FAA and EPA to determine new initiatives to implement changes without costing operators and manufacturers as much time and money. The final ruling will provide manufacturers with newer, more sustainable standards moving forward and is in line with the industry goal of net-zero emissions by 2050.