Emissions Certification Policy and Guidance

Regulated emissions include raw fuel vented to the atmosphere during normal engine shutdown, and the following products of combustion in engine exhaust for certain classes of engines: smoke (SN), hydrocarbons (HC), carbon monoxide (CO), and oxides of nitrogen (NOx). The International Civil Aviation Organization (ICAO) has most recently adopted a reporting requirement for non-volatile particulate matter (nvPM) emissions from engines and emissions limits for carbon dioxide (CO2) from aircraft.

Review Recommended Best Practices for Quantifying Speciated Organic Gas Emissions From Aircraft Equipped with Turbofan, Turbojet, and Turboprop Engines  and Guidance for Quantifying Speciated Organic Gas Emissions from airport Sources

Which engines do the emissions certification requirements apply to?

The Engine Fuel Venting and Exhaust Emissions certification requirements (14 CFR Part 34) apply to civil airplanes that are powered by aircraft gas turbine engines of the classes specified in the rule. The engines must have U.S. standard airworthiness certificates or foreign airworthiness certificates that are equivalent to U.S. standard airworthiness certificates.

U.S. manufactured gas turbine engines or foreign manufactured gas turbine engines that are installed in U.S. manufactured Part 23 or Part 25 aircraft must show compliance to the 14 CFR Part 34 fuel venting and exhaust emissions requirements.

Who is authorized to set emissions certification requirements?

The Secretary of Transportation is mandated, by authority of Section 232 of the Clean Air Act (CAA), to "prescribe regulations to ensure compliance with all standards prescribed by the Administrator" (of the Environmental Protection Agency).

The EPA, similarly, gets its authority from Section 231 of the CAA that mandates EPA to determine "the extent to which such emissions affect air quality in air quality regions throughout the United States," and "the technological feasibility of controlling such emissions.“

The EPA sets the Emissions Standards and FAA sets and administers the Certification Requirements for aircraft and engines to demonstrate compliance with the Emissions Standards. In addition, Section 233 of the CAA prohibits states and local communities from setting their own standards.

What is the basis of these requirements?

The standards, as developed by EPA are issued in Title 40 Part 87 of the Code of Federal Regulations (40CFR87), "Control of air pollution from aircraft and aircraft engines." The requirements as developed by FAA in association with EPA are issued in Title 14 Part 34 of the Code of Federal Regulations (14CFR34), "Fuel Venting and Exhaust Emission Requirements for Turbine Engine Powered Airplanes.“

Independently, the International Civil Aviation Organization (ICAO) issued, as one of their International Standards and Recommendation Practices, Annex 16 to the Convention on International Civil Aviation, Environmental Protection, Volume II, Aircraft Engine Emissions and ICAO Annex 16, Volume III CO2 emissions. The EPA has adopted, by reference in 40CFR87 selected sections of Annex 16 that describe requirements for sampling, measurement and the analytical determination of compliance. These requirements are reflected in 14CFR34 in sections 34.64, "Sampling and analytical procedures for measuring gaseous exhaust emissions;" 34.82, "Sampling and analytical procedures for measuring smoke exhaust emissions;" and sections34.71, "Compliance with gaseous emissions standards," and 34.89, "Compliance with smoke emissions standards.“

The regulations are complex and offer challenges in arriving at and maintaining uniformity of interpretation and application by engine manufacturers and regulatory authorities. To address this problem, FAA has issued an Advisory Circular, AC34-1B, "Fuel Venting and Exhaust Emissions Requirements for Turbine Engine Powered Airplanes."  ICAO subsequently developed an equivalent Environmental Technical Manual, "Volume II Procedures for the Emissions Certification of Aircraft Engines.“

What is the basis of fuel venting and exhaust emissions requirements?

The Clean Air Act (CAA) of 1970 directs EPA to establish air pollution standards, including those applicable to aircraft exhaust. Under Sections 231 and 232 of the CAA, EPA consults with FAA to ensure that the development and application of requisite technology is possible. The FAA issues regulations under 14 CFR Part 34 to enforce compliance with EPA emissions regulations under 40 CFR Part 87.

Which FAA organization is responsible for maintaining emissions certification requirements?

AEE-300 has responsibility for maintaining the fuel venting, exhaust and aircraft emissions standards of 14 CFR Part 34, as well as approving new or equivalent test procedures under 14 CFR Part 34, and processing applications for exemptions per 14 CFR Part 11. In addition, AEE-300 provides policy and guidance relative to this rule and promotes international harmonization of emissions standards through ICAO's Committee for Aviation Environmental Protection. AEE-300 also coordinates with EPA on aviation emissions standards codified in 40 CFR Part 87. Finally, AEE-300 provides policy and guidance via Advisory Circular AC-34. 

Partnerships

The program has many partners and stakeholders including aviation professionals, researchers, manufacturers, airlines, airports, airport communities, federal agencies, environmental non-governmental organizations, foreign governments and international organizations. The program benefits from these varied partners by ensuring that the Environment & Energy (E&E) Research and Development (R&D) Portfolio is well-balanced, relevant, non-duplicative, and addresses the needs of a broad range of stakeholders. These partnerships include, but are not limited to following:

Domestic Partners

• ACRP - The Airport Cooperative Research Program (ACRP) is an industry-driven, applied research program that develops near-term, practical solutions to airport challenges. ACRP is authorized by Congress, sponsored by the Federal Aviation Administration, and managed by the Transportation Research Board (TRB).
• ASCENT - The Aviation Sustainability Center is the FAA’s Center of Excellence (COE) for Alternative Jet Fuels and Environment. ASCENT works to create science-based solutions for the aviation industry’s efforts to reduce the environmental impact of aviation. The center includes 16 universities, 4 affiliate universities, 14 Federal Partners and non-profit research institutes, and more than 70 industry partners.
• BR&D – The Biomass Research and Development Board is an interagency collaborative co-chaired by U.S. Department of Agriculture and Department of Energy and tasked with implementing the federal Bioeconomy Initiative, enables focused federal agency coordination on SAF via an Advanced Aviation Fuels Interagency Working Group (AAF IWG).
• CAAFI® - The Commercial Aviation Alternative Fuels Initiative® is a forum for exchange and coordination among government, academic and aviation industry stakeholders to address challenges and engage with the emerging sustainable aviation fuels industry.
• CLEEN – The Continuous Lower Energy, Emissions, and Noise Program is a cost-sharing program with Industry that aims to develop and expedite the introduction of environmentally promising aircraft technologies and sustainable alternative fuels that reduce aircraft noise, emissions, and fuel burn.
• FICAN – The Federal Interagency Committee on Aviation Noise scope is to provide the necessary technical forum for participating agencies to coordinate on aviation noise R&D. The committee includes the Department of Defense (DOD – Air force, Army, and Navy), the Department of the Interior (DOI, represented by the National Park Service), the Department of Transportation (DOT, represented by the Federal Aviation Administration), the U.S. Environmental Protection Agency (EPA), the National Aeronautics and Space Administration (NASA) and the Department of Housing and Urban Development (HUD).
• U.S. Federal Agencies – The E&E R&D program also directly coordinates activities with many Federal agencies through a variety of activities and projects.  In addition to the agencies already mentioned before, the program also collaborates with the National Institute of Health (NIH), the U.S. Department of Agriculture (USDA) and the U.S. Department of Energy (DOE) 

International Partners

• DLR – The German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt e.V.)  is the national center for aerospace, energy and transportation research of Germany. The main objectives of DLR’s aeronautics research are to avoid the emission of pollutants from aircraft, to reduce aircraft noise, to develop uncrewed flight systems and to digitalize the aviation industry.
• EASA – The European Aviation Safety Agency (EASA) is responsible for ensuring safety and environmental protection in air transport in Europe. It carries out certification, regulation, standardization, and also performs investigation and monitoring. It collects and analyzes data, drafts and advises on safety legislation and coordinates with similar organizations in other parts of the world. 
• GARDN – The Green Aviation Research and Development Network (GARDN) was a non-profit organization created in 2009 with funding from the Business-Led Network of Centres of Excellence (BL-NCE) of the federal government and Canadian aerospace industry. Its mission was to help support and increase Canada’s competitiveness in the aerospace industry by reducing the environmental footprint of the next generation of aircraft, engines and avionics systems developed in the country.
• ICAO CAEP – The International Civil Aviation Organization’s Committee on Aviation Environmental Protection is a technical committee of the ICAO Council and is tasked to assists the Council in formulating new policies and adopting new Standards and Recommended Practices (SARPs) related to aircraft noise and emissions, and more generally to aviation environmental impact.
• Swiss FOCA – The Swiss Federal Office of Civil Aviation is the Swiss civil aviation agency and is a division of the Federal Department of Environment, Transport, Energy and Communications. The office strives for a high level of safety and sustainable development in Swiss civil aviation.