State of the Industry Transition to Unleaded AvGas

Eliminate Aviation Gasoline Lead Emissions (EAGLE) Initiative: 
Commitment to an Unleaded Fuel 

The General Aviation industry trade associations, the American Petroleum Industry and the Federal Aviation Administration established the Eliminate Aviation Gasoline Lead Emissions (EAGLE) initiative in 2022 with the goal of eliminating aviation gasoline lead emissions before the end of 2030 without adversely affecting the safe and efficient operation of the general aviation fleet.  Consistent with the Congressionally directed National Academies of Sciences, Engineering and Medicine’s 2021 Consensus Study Report “Options for Reducing Lead Emissions from Piston-Engine Aircraft”, EAGLE’s initiatives focus on a multi-faceted approach to reduce and eliminate lead emissions by way of four integrated pillars :  

1. Facilitate infrastructure development from refining to distribution into wing, as well as options for communities to pursue near-term reductions of lead emissions 

1. Concurrently conduct Research & Development on technical solutions for safety and to minimize potential impact of transitioning to an unleaded fuel (in the event certain aircraft are impacted by a transition to an unleaded replacement fuel) 

1. Support development and deployment of a viable unleaded fuel to replace 100LL that meets the safety needs of the fleet.  This includes fuels assessed through the industry/FAA Piston Aviation Fuels Initiative (PAFI) test program and traditional FAA type certification program. 

1. Support Environmental Protection Agency (EPA) and FAA promulgation of regulations to eliminate lead emissions. 

Four Fuels Pursuing Unleaded Solutions 

There are two pathways available to obtain FAA authorization for the use of a new fuel: (1) FAA aviation fuel fleet authorization process established by Congress through a collaborative industry/government testing program called the Piston Aviation Fuels Initiative (PAFI); and (2) traditional FAA aircraft Supplemental Type Certification (STC) process.  There are two active fuels in the PAFI test program as part of the development and testing process: fuel producers Phillips 66 teaming with Afton Chemical, and LyondellBasell partnering with VP Racing. Both fuel developers are actively engaged in the program and mini durability testing is expect to be completed in July, 2023. 

Two fuel developers are pursuing traditional FAA STC approval of high-octane unleaded fuels: General Aviation Modifications Inc. (GAMI) and Swift Fuels Inc.  On September 1, 2022, FAA issued an Approved Model List Supplemental Type Certificate (AML-STC) to GAMI for G100UL unleaded avgas. This AML-STC represents the first FAA authorization for use of a high-octane unleaded fuel for general aviation piston aircraft and moves the industry a step closer to an unleaded future.  Swift is also developing a high-octane unleaded fuel and has made application to the FAA while working to obtain an AML-STC for eligible aircraft and engines. Swift has publicly stated that it hopes to achieve FAA AML-STC approval for a 100-octane unleaded 100R fuel  by 2023. The “R” stands for renewable, as it will contain a renewable fuel blend. 

The issuance of the first AML-STC to GAMI for their high-octane unleaded avgas marks the beginning of the complex work that remains to identify a commercial pathway for production and distribution necessary for the fuel to be viable in the marketplace and become available at airports across the country for purchase and use by aircraft operators. While the proprietary STC process provided a pathway for FAA authorization to use the fuel in engines and aircraft, deployment by other stakeholders such as producers, distributors, FBOs, airports and engine/aircraft manufacturers must also have an adequate understanding of a new fuel necessary to make the business decision on whether to accept the risk and liability of purchasing, producing, distributing, transporting, handling, dispensing and supporting the operation and use of the fuel and continued airworthiness of their respective products, including warranties. 

Broad Industry Acceptance and Understanding of Fuels Needed  

Traditionally, much of this stakeholder understanding and acceptance of a fuel is gained as the developer works through the consensus standard process to obtain a production specification through ASTM International.  ASTM is the globally recognized industry consensus body in which the producers, distributors, providers, users and many other subject matter experts regarding aviation fuels conduct peer review assessments of proposed fuel definitions toward the establishment of broad industry stakeholder consensus and acceptance of a fuel specification to facilitate production, distribution and its use (ASTM specifications are also used for commercialization of automotive and all other transportation fuels). This consensus process includes review of fuel definition data provided by developers such as composition, performance properties, applicability of test methods and production quality considerations which are fit for purpose in terms of intended use for aviation. Producers, distributors, FBOs, airports, OEMs and consumers are being asked to make business, financial and operational decisions that affect their short and long-term viability and the provision and use of fuels which directly impacts aviation safety therefore require the information necessary to understand such fuels.   

The EAGLE initiative provides broad government and industry stakeholder support for the development and deployment of a viable unleaded fuel to replace 100LL that meets the safety needs of the fleet with the least impact.  This includes fuels assessed and authorized through the industry/FAA PAFI test program and traditional FAA type certification program such as STC. The PAFI testing protocols were developed by an expert group of aviation manufacturers and FAA and the test plans and fuel data support both obtaining an FAA fleet authorization and ASTM production specification for consensus agreement among all stakeholders.  

The FAA type certification process is proprietary with no visibility of test methods or information about the fuel. If a fuel developer chooses to not pursue the fuel industry custom, practice and norm of establishing an ASTM consensus standard production specification that stakeholders rely upon for all other aviation fuels, a fuel sponsor must undertake themselves alternate means for socializing and providing a level of understanding necessary for stakeholders in the supply chain to support deployment and use of a new fuel. Phillips66/Afton Chemical and LyondellBasell/VP Racing’s participation in PAFI will provide the data utilized to obtain an ASTM production specification.  Swift has stated that it also is seeking to obtain an ASTM production specification. 

EAGLE Commitment to Supporting All Unleaded Fuel Candidates 

EAGLE’s efforts to support all fuel sponsors continue as member companies of the sponsoring associations provide technical support to the PAFI testing of the Afton Chemical/Phillips66 and LyondellBasell/VP Racing fuels.  Additionally, GAMI and Swift Fuels are supported in their efforts as sponsoring associations and member companies, including producers, distributors, FBOs, and manufacturers who continue to work to facilitate stakeholder understanding of the fuels to enable support for deployment and use.  Two aircraft manufacturers, Cirrus Aircraft and Robinson Helicopter, have entered into agreements with GAMI to conduct independent assessments of the new fuel.  EAGLE’s R&D pillar lead is facilitating status updates with other stakeholders.  EAGLE recently participated in a meeting hosted by AOPA with the leading avgas distributors and both STC fuel developers GAMI and Swift to discuss respective business needs to support deployment into the marketplace.  

EAGLE supports each of the fuel developers Phillips66/Afton, Lyondellbasell/VP Racing , GAMI, and Swift Fuels.  EAGLE understands that each company makes their own business decisions in choosing what path to pursue for FAA approval/authorization and their approach to commercialize and deploy into the market.  However, regardless of their approach, FAA safety approval/authorization and acceptance and support of key stakeholders who must make the business decision to produce, purchase, transport, store, dispense and use a new fuel are necessary in order to be successful in commercialization and deployment into the market. 

The Transition to Unleaded AvGas is Underway 

Of the nearly 20,000 landing facilities in the US, approximately 5,100 are public-use airports with the balance consisting of military, private, helipads, or restricted facilities such as hospital or offshore oil rig landing platforms. Approximately 65% or 3,300 public-use airports sell fuel, principally 100LL low lead fuel, while 30 or so currently sell 94UL unleaded fuel as well 100LL low lead fuel. A handful of public use airports sell only UL94, leaving a critical safety void for high compression aircraft still needing 100LL until a high-octane unleaded fuel is widely available across the US.  

Airports experiencing significant community pressure to reduce or eliminate lead emissions are finding ways to maintain 100LL while also reducing lead emissions. Centennial Airport (APA) for example, recently  provided a path to allow the addition of 94UL unleaded avgas on to the airport by working with their local flight schools and an FBO willing to make an extra tank and fuel truck available for unleaded fuel use. Flight training is critical to feeding the demand for commercial airline pilots. With the addition of 94UL, APA expects to lower lead emissions in and around the airport to close to 80 percent by some estimates. Other airports are following suit, resources permitting. In some cases, airports are assisting FBOs and tenants by contributing to costs associated with aircraft authorizations to utilized 94UL. Communities are encouraged to assist resource-challenged airport with funding to help airports purchase and install tanks and trucks for unleaded fuel storage and sale in the short term.  

EAGLE is committed to coordinating pathways for infrastructure development from refining, blending, storing, and distribution into wing. This is no small task given the number of airports involved; however, the sale and use of UL94 is a great interim step in reducing lead emissions at the source while establishing the infrastructure for one or more fuels in the future, much like the ‘regular’ and ‘premium’ blends we find at automobile  gas stations.  

Respectfully submitted on behalf of EAGLE, the associations representing the general aviation and Petroleum industries, as well as the Federal Aviation Administration— 

Lirio Liu, FAA 

Mark Baker, AOPA  

Pete Bunce, GAMA 

Jack Pelton, EAA 

Ed Bolen, NBAA 

Curt Castagna, NATA 

Greg Pecoraro, NASAO 

James Viola, HAI 

John Cudahy, ICAS 

Todd Hauptli, AAAE 

Prentiss Seales, API 

Robert Olislagers, EAGLE