Wherever and whenever I fly around this great country, our members have a big issue on their minds: When will they have access to the 100-octane unleaded fuel they’ve been hearing about? And is 100LL going away?
Those are important questions as there is a lot of information—and misinformation—swirling about, and it’s important that facts rise above the noise.
Let me say right off the bat that we in general aviation want lead out of avgas as soon as practical. As most know, industry and the FAA have established a goal of removing lead from avgas no later than 2030. This is an aggressive timeline and one that I believe we can meet. It’s going to take everyone to work cooperatively and in good faith to get there. But let there be no doubt, one of our highest priorities is a transition to unleaded fuel that is safe and smart—and deploying a solution that works for the entire GA piston aircraft fleet.
Before we address at what stage of development the new unleaded fuels are, it's important to get a quick review of what’s available now and what challenges we face in finding a widely available unleaded fuel for every piston engine in the fleet.
Swift Fuels' UL94, a 94-octane unleaded fuel good for lower compression engines, is currently available at 36 U.S. public-use airports. Before using this fuel, currently, you must obtain a supplemental type certificate (STC) specific to your aircraft and engine. Higher compression engines, such as those used on many Beechcraft Bonanzas and Barons, as well as Cirrus SR22s, cannot use this lower-octane fuel as it may not prevent dangerous, engine-damaging detonation. We’ve already seen some unfortunate incidents of misfueling.
There are also STCs available that enable lower compression aircraft engines to use ethanol-free automotive gasoline (mogas). About 75 airports across the country still sell this type of fuel, but it is increasingly difficult to find mogas that does not contain some percentage of ethanol.
While airplanes with lower compression engines make up 70 percent of the GA piston fleet, they only burn about 30 percent of the 100LL. Higher compression engines use 70 percent of the 100LL supply. This is, in part, the reason we need 100LL available at our airports during this transition. More importantly, it is a matter of safety—exactly why Congress has included language in the FAA reauthorization bill that would require that 100LL remain available at airports while we transition to unleaded fuel.
Turning to fuels in development, General Aviation Modifications Inc. (GAMI) has developed G100UL, a 100-octane unleaded fuel that is FAA approved, via STC, for all GA spark-ignition piston airplanes. Rotorcraft certification work is ongoing. GAMI is currently seeking a path to commercialize G100UL, which requires agreements with partners to blend and distribute the fuel nationwide. This is no simple feat, as national distribution will take several years if everything goes exactly as planned.
There are members and some in the media who have proclaimed that this FAA approval has solved everything, and they question why we are even looking at other fuels.
In short, the STC process is proprietary by its very nature, and engine manufacturers and fuel distributors simply want to learn more about the GAMI fuel. Although there is no legal requirement for GAMI to pursue an American Society for Testing and Materials (ASTM) fuel specification, some suggest it should do so. And while GAMI has reportedly incorporated many ASTM testing standards in pursuit of its FAA STC approval, the company remains hesitant to go through such a cumbersome and complicated process that could take years. I believe having some type of industry consensus—not necessarily an ASTM standard—would be very helpful in moving the GAMI fuel forward.
Swift has also pursued the STC pathway with its 100R unleaded fuel and is seeking an ASTM specification. Swift has indicated that it may receive FAA approval for its fuel by the end of this year.
Two fuel candidates are pursuing testing through the Piston Aviation Fuels Initiative (PAFI) pathway, which is administered by the FAA: one from the LyondellBasell/VP Racing team, and the other from Phillips 66/Afton Chemical.
Whether through the STC process, ASTM consensus specification, or some type of industry consensus, any new 100-octane unleaded fuel needs to be widely available and safely mix with 100LL. And if there are multiple 100 unleaded fuels approved for wide distribution, they all must be fungible with one another. This fungibility issue is an important one and should be addressed as fuel testing goes forward. Ultimately, the market will determine how many fuels can realistically compete in this space.
Moreover, most U.S. airports do not have the financial wherewithal to add additional fuel tanks (or trucks). And for those that do, there can be confusion in having multiple tanks with multiple fuels that may or may not mix with each other.
AOPA has been advocating for a program that would provide an opportunity for any FAA-approved 100-octane unleaded fuel to be demonstrated to work in a way to help build industry confidence. The demonstrations will produce data on whether the fuel(s) will reduce engine maintenance or have any impact on spark plug fouling, valves, and engine oil. And I am pleased the FAA has agreed to make significant funds available for this very purpose.
The Environmental Protection Agency endangerment finding, expected to be released in October, will require the removal of lead from fuel, something we’ve been focused on for years. But please don’t panic—100LL will remain available at airports during this transition. This endangerment finding kicks off a regulatory process that will require the FAA to develop a path forward for removing lead from avgas.
I have the privilege of co-chairing a government-industry partnership called Eliminate Aviation Gasoline Lead Emissions (EAGLE) that will be involved in helping develop these regulations. At the same time, it is important to reaffirm the role of EAGLE: It’s not to make fuel, not to approve fuel, but rather to facilitate information and communication among those involved in the safe transition to replace 100LL.
AOPA is working every day with a sense of urgency. It will take the FAA, fuel companies, engine manufacturers, fuel distributors, FBOs, and every other party to this issue to attain our safe and smart transition to unleaded fuel by 2030. I say, let’s get this done as quickly and as safely as possible.