Technology, Sustainable Aviation Fuels, and Operations

Through the Continuous Lower Energy, Emissions, and Noise (CLEEN) program and the Aviation Sustainability Center (ASCENT), the FAA’s Center of Excellence (COE) for Alternative Jet Fuels and Environment, the FAA is supporting Research and Development (R&D) to develop new aircraft and engine technologies and sustainable aviation fuels (SAF). Technologies developed by this program will result in a fleet of aircraft that have lower noise, use less fuel, and produce fewer emissions. This program also provides test data, analyses, and methodologies to support SAF supply development and ensure novel jet fuels are drop-in compatible with today’s fleet of aircraft, certified as being safe for use, and appropriately credited under the International Civil Aviation Organization (ICAO) Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA). 

Additionally, ASCENT supports research on operational measures to reduce aviation's environmental impacts.

Aircraft Technology

Through the CLEEN program, the FAA and industry are working together to develop technologies that will enable manufacturers to create aircraft and engines with lower noise and emissions, as well as improved fuel efficiency. Technologies accelerated by the CLEEN program have relatively large technological risk. Government resources help mitigate this risk and incentivize aviation manufacturers to invest in developing these technologies. By cost sharing the development with the FAA, industry is willing to accept the greater risk. Once entered into service, the CLEEN technologies will deliver noise, fuel burn, and emissions benefits throughout the fleet for years to come. 

Funding from the Environment & Energy (E&E) portfolio also supports efforts by ASCENT to develop innovative technological solutions to reduce noise, emissions, and fuel burn from subsonic and supersonic aircraft. While CLEEN focuses on partnerships with industry, the ASCENT aircraft technology work provides a complementary venue for university-led research to advance the state of the art and disseminate the learnings from these projects broadly across the industry. For more information on the technology projects under ASCENT, please visit:

Sustainable Aviation Fuels (SAF)

In addition, the portfolio provides funding to advance SAF fuel testing, analysis, and coordination efforts. SAF is a fuel made from renewable resources that meets a minimum of a 50% reduction in life cycle greenhouse gas emissions compared to conventional fuel. Testing and analysis work is conducted via a range of ASCENT research projects to accelerate qualification of new drop-in fuels by ASTM International and further understanding of the environmental, economic, and production potential of SAF. For more information on ASCENT SAF projects, please visit:

Funding also supports the Commercial Aviation Alternative Fuels Initiative® (CAAFI®), a public-private partnership, to engage and enable coordination between our R&D efforts and the commercial aviation and emerging alternative fuels industries.

FAA research also supports "The Sustainable Aviation Fuel Grand Challenge” a government-wide initiative led by the U.S. Department of Energy (DOE), the U.S. Department of Transportation (DOT), and the U.S. Department of Agriculture (USDA) to reduce the cost, improve the sustainability and significantly expand the production and use of SAF. An interagency effort is taking a comprehensive approach to federal actions that will enable industry to build out the SAF supply to meet the near term goal of 3 billion gallons per year of SAF by 2030 and place the U.S. on a trajectory to meeting 100% of aviation’s fuel needs by 2050 (an estimated 35 billion gallons per year). 


The FAA sponsors research to develop and implement clean, quiet, and energy-efficient operational procedures to help mitigate the environmental impacts of aviation. This research is conducted in coordination with other government agencies (e.g., NASA) as well as non-governmental aviation stakeholders, including industry, academia, and airport communities. The FAA aims to develop innovative, cost-effective solutions to reduce noise, fuel use, and emissions through aircraft operations while maintaining or enhancing the safety, efficiency, and predictability benefits of NextGen.

For more information on these operations research projects, please visit:


CLEEN, CAAFI®, and ASCENT are conducted in partnership with a wide range of aviation stakeholders that leverage resources from the private sector. CLEEN is a public-private partnership where the industry contributes a cost share that matches or exceeds the amount provided by the FAA. As a coalition among the FAA, airlines, aircraft and engine manufacturers, industry, and other U.S. government agencies, CAAFI® lends a collective focus to the combined effort to enable the emerging SAF industry. ASCENT, like all FAA COEs, requires a hundred percent cost-share from non-federal sources and benefits from an advisory committee with robust participation from a wide range of aviation stakeholders, including industry. The continuing work of CLEEN, CAAFI, and ASCENT to develop novel jet fuels will help ensure aviation has a wide range of energy options for decades to come.

Last updated: Monday, September 19, 2022