FAA Approves Testing Landmark For Unleaded Avgas Contender


The Eliminate Aviation Gasoline Lead Emissions (EAGLE) team announced today (Nov. 29) that the first high-octane unleaded aviation fuel has reached an FAA milestone. According to an FAA announcement today, the agency “has approved the advancement to full-scale engine and flight testing of unleaded UL100E aviation fuel for piston-engine aircraft developed by LyondellBasell Industries/VP Racing. The UL100E fuel successfully passed a 150-hour engine durability test under the Piston Aviation Fuels Initiative (PAFI), a collaborative industry/government testing program. LyondellBessell/VP Racing UL100E is the first unleaded fuel to pass the PAFI 150-hour durability test phase.”

Lyondell/Basell is an international petroleum processing company with refineries in Germany, the Netherlands, and four in Texas. VP Racing specializes in competition racing fuels, including supplying high-octane fuel for competitors in the Unlimited Class at the Reno Air Races.

The next phase of PAFI testing involves full-scale engine and airframe testing and is expected to last 12 to 18 months. Controversy throughout the general aviation community swirls around the difference between the PAFI ASTM pathway to fleetwide approval versus the Supplemental Type Certification (STC) route chosen by the General Aviation Modification Inc. (GAMI) for its G100UL product.

According to the EAGLE statement, the PAFI process “rigorously tests candidate fuels through various phases including evaluation of toxicology and environmental considerations, material capability, engine durability and detonation, and aircraft performance and operability.” The purpose of the trials is to help develop an industry consensus ASTM international production specification, leading to an FAA-generated fleet authorization for the fuel. “The goal of PAFI is to test, not produce, fuels that can ensure both capability and safety within the piston-engine aircraft fleet as well as commercial viability for deployment,” according to the EAGLE statement. It is noteworthy that EAGLE cites the factor of “commercial viability for deployment” in its statement.

Curt Castagna, EAGLE co-chair and president of the National Air Transportation Association (NATA), which represents a wide range of general aviation industry stakeholders, said, “The LyondellBasell/VP Racing achievement marks an important waypoint on the path to a more environmentally friendly future for aviation fuel and demonstrates the progress made through our government and community partnership. EAGLE celebrates this milestone and looks forward to more opportunities to recognize industry ingenuity and innovation.” Castagna’s EAGLE co-chair, FAA Executive Director of Aircraft Certification Service Lirio Liu, added, “This is another important milestone for a safe General Aviation transition to unleaded fuel and for our goal to eliminate lead emissions by the end of 2030.”

Mark Phelps
Mark Phelps is a senior editor at AVweb. He is an instrument rated private pilot and former owner of a Grumman American AA1B and a V-tail Bonanza.


  1. How is this “different” than the GAMI no-lead fuel–developed by private enterprise but spurned by the FAA after 11 years of development (according to Aviation Week (without saying WHY?)

      • Quite the contrary . STC v. ASTM certifications are concerned.
        More than just the ” headers ” on the paper shuffle.
        In so far as the legal beagles are concerned.
        Akin to doing your income tax returns yourself, verses having H&R Block do them.

        • Hardly. More like hiring H&R Block vs hiring your own qualified CPA to do your taxes. THe GAMI fuel has been fully and rigorously tested. Fleetwide STCs are not issued lightly.

          • A large percentage of STCs are obtained by third parties. The STCs only cover the changes from the aircraft’s existing certification basis (which is the original TC plus any previously installed STCs.) An STC may be for a single aircraft, a single aircraft type, or for multiple types (an “Approved Model List STC” or AML STC). To the contrary, an industry consensus ASTM international production specification, will lead to an FAA-generated fleet-wide entire General Aviation authorization to a higher degree of internationally recognized and accepted standards.

  2. For the love of all that’s holy, just make available unleaded Avgas or no-ethanol MoGas !
    Most of us GA planes do NOT need 100 octane.
    Keep working on the 100 octane users for the nest 40 years….

    • When 80 octane went extinct, I put in high-test auto gas in its place. Certified minimum of 96 octane–certified no alcohol–a floating suction system to be sure there is no water–a “dead-stop” if any water or filter blockage DID occure–and a bill of lading right from the refinery attesting to the content (it assures the pilot of the content, and protects us). We priced it $1 a gallon higher than auto fuel at the local station. More than a decade later, we still sell perhaps 10% of the volume of 100 octane. I use it in our own fleet, and the pipeline patrollers love it–but for far too many pilots, they just won’t burn auto gas–even with all of those safeguards.

      • Thank you! I have been using Mogas from the gas pumps for 30 years since 80 went away. I test each batch for alcohol with a simple fuel/water alcohol extraction test which is a small beverage bottle with an inked line, filled with water with fuel placed on top, capped and shaken vigorously. No level change, no alcohol. My engine has run well past TBO on two runs with very clean interior according to the rebuilder. I preferentially use and buy mogas from airports away from home but cannot get it at my based airport. I would gladly pay a price premium over street pumps just to avoid the hassle of transferring fuel. My oil analysis shows low but non-zero lead levels and all wear metals are acceptable in an O-470R. There is ample data from Petersen and EAA that mogas works well in aircraft if we can keep the corn whiskey out of it.

        As for the “one size fits all” we have never had a one fuel fits all in aviation. As far back as I can remember we had 100 (GREEN), 100LL (BLUE), and 80 (RED). There has never, until the demise of 80, been a one size fits all and I’m guessing that if the manufacturers had not said higher octane can be used in lower octane engines we would still have two grades of fuel.

        As for the ASTM v. STC, if we go the STC route, there will not be a blanket STC that says you can use manufacturer A’s 100UL with manufacturer B’s STC. What GAMI has done is to issue an STC for its fuel and only its fuel. It won’t work with SwiftFuel. So you need one from each. If more suppliers enter the field it’s easy to see where this leads. Already there are two STCs for mogas. Petersen which allows mogas with or without lead or the EAA which allows unleaded mogas only (I think). The paperwork process (and the cost) must be reasonable and multiple fuel STCs for each manufacturer is not for most operators who use their airplanes for more than 3 loops around the pattern every 90 days.

      • We need to listen to these people. There are already two tanks at most airports. Gasoline and Jet Fuel. The airframers and engine manufacturers have put almost no comparable effort to make material changes to the fuel requirements of their products. Its time for Cessna to approve (on their TCDS, not STC) an engine model of lower compression ratio (same horsepower, with compensating improved flow or ignition) on an existing legacy airframe. UL94 is approved avgas and we need to be using it in place of 100LL. — 44 year A&P/IA

    • This process has nothing to do with ” most of our ” puddle jumpers ” do not need 100 octane .”

      It is all about the the ” Inclusive ” factoring on an internationally accepted process now ; ASTM standards accepted only and ensuring that 285 hp Bonanzas and 300 hp plus Malibu’s are satisfied with a ” one size fits all ” 100LL replacement.

    • What about for those who do need 100 octane? Do you really think most airports are going to foot the costs for extra tankage on a low-volume fuel (compared to 100L) that may not pay for itself?

      Try talking to your local airport administrator and convince them to add the extra tankage.

      • Pay for itself? All it takes is a word from the FAA and 1/100000000 of what was thrown down the drain on overseas “projects” as of late.

      • Those airports had or have that extra tankage from when they carried 80 and 100. When 80 was still available most of the airports I flew into had both plus JetA. My based airport still has the 80 tanks and did switch to mogas for years. It decided to drop mogas a decade ago, and would like to drop 100LL and just sell JetA.
        What economic analysis changed that now makes it infeasible to carry two grades of fuel (3 if you count JET-A).

        • By now, many of those older tanks that carried and held 80/87 octane fuel and then in some cases, later on held mogas without ethanol for use by STC holders; are now obsolete to current standards as per the EPA, or simply no longer useable.

    • A partial solution is just that – partially addresses the problem – if the goal is to eliminate lead, then grounding a bunch of airplanes isn’t a good solution – we need something that works for everyone, and then we can move forward – I’m old enough to remember HD TVs (and before that.) It wasn’t until we had a solution for everyone that it came into being.

      • Waiting 40 years now for another “one solution”. It sure looks stupid that a convenience store can have diesel and 3 grades if gasoline but airports can’t have but one solution.

        • As for the C-store’s 3 grades, the Mid-Grade is just a blended at the pump fuel, so only 3 actual tanks are needed – 87, 91[2], and diesel. Some C-stores are now carrying the radically overpriced Non-Ethanol fuel at ~ $1.00/gal more than 91, especially near recreational lakes. Boaters loathe the “corn squeezing’s” in their fuel and most marinas have Non-Ethanol at “Marina Prices’, but the boat captains don’t seem to worry about putting Ethanol in their bellies. If the federal subsidies for Ethanol in gas went away, mogas would ALL be Non-Ethanol within a few weeks when it became more expensive to produce.

    • There’s plenty of no ethanol 80/87 fuel available available. Several gas stations sell Pure Gas in separately marked pumps and it’s good stuff. There’s even a nationwide published station locater. After 100LL got close to $7/gal, I purchased a Peterson STC and I’ve been using it for some years in my Franklin engine. For very little money I built a small fueling station on a cart, no 5 gal cans, it fuels just like the self-serve. Bought the pump,(12gpm) from a farm supply company with an inline particle and water filter and the 35-gal tank from a racing supply company. I power the pump with a riding lawn mower battery so I can just roll it into the fueling position. It’s so easy and fuel is under $3 gal. The setup is good for local hamburger flying, not cross-country, if you X-country you’ll have to pump 100LL which is still compatible. If you want more info on my setup and how I get the fuel, pbsroth@gmail.

      • Well aware of the non-ethanol mogas branded station map locator. Nearest one to me is 120 miles away. I too have the Peterson STC since about 1986. Used it all the time in my C-140, Ercoupe, Aeronca 11AC until ethanol whiskey was put into it on farmers demand. Now, I strictly use 100LL, lean like hell and a splash of MMO and TCP.

    • Two issues:

      One, the overwhelming majority of small-town airports cannot offer more than one type of gasoline-base fuel–they simply do not have the storage facilities.

      The owners with big money fly aircraft that require 100 octane fuel; they are the ones that policy makers listen to.

  3. Sounds like a rerun of the last 20 years. There is not going to be a replacement 100UL it is just a dream we revisit over and over again. Any chance we could quit torturing the 70% that don’t need this Unnecessarily Expensive 100UL that will never be. Can we start a program to distribute the 94UL by offering it next to the 100LL. At least we might be moving forward instead of going nowhere, which has been the normal for more than 20 years now.

    • Talk to your local airport’s manager and/or FBOs about adding in a second fuel tank. I expect you will probably be pointed to where the nearest door is.

    • I fully agree! And, get Cirrus to put their own unleaded engines (continental Jet-a) in their own airplanes. We are foolishly depending on Tetraethyl Lead because the engine manufacturers will not lower the compression ratios and make up the power loss with electronic ignition and more efficient intake and exhaust flow.

  4. GAWD! What a waste of time & money! I wonder how much time & money was spent coming up with the EAGLE acronym. I’ve been to many a planning meeting on K Street, and know first hand how politics and who’s brother-in-law owns the desired outcome. Sickening!

  5. Clearly; the FAA and the powers that be aling with and inclusive of the alphabet soup groups are proving that the fuel that becomes the 100LL replacement is the one that fully conforms and is approved by ATSM standard and not anything else.
    EAGLE has shown that to indeed be the case.

    We can forget STC approvals and processes.

  6. If one reads the above posted news release carefully and digests the statement of the FAA, one clearly sees that the focus is 100% on ” an internationally designed, approved and accepted standard. ”
    Internationally— and that means ASTM sanctioned .


    “The purpose of the trials is to help develop an industry consensus ASTM international production specification, leading to an FAA-generated fleet authorization for the fuel. “

  7. ASTM International, formerly known as American Society for Testing and Materials, is an international standards organization that develops and publishes consensus technical standards for a wide range of materials, products, systems, and services.

    Completely different route than STC and GAMI.

  8. The volume of AVGAS sales is too low to have two separate fuels. The TEL producers wouldn’t have a large enough market to remain viable. The FAA wouldn’t fund the installation of a second parallel fuel tank for fear of responsibility for leaking tanks.

    So we sit waiting for the clock on leaded fuel to click down to zero without a clear plan in place.

    • We see that the FAA, AOPA do not care about growing GA; failing to have even multiple tanks like any gas station in the country. No, getting rid of small planes sure seems to be a side goal of what they are doing.

      • The sad proof is General Aviation is just about impossible to grow. It’s very costly and that keeps new interest down. New aircraft to replace those out of service are too expensive for new entry owners. So, the 40 to 50-year-old existing fleet is all there is. And they fall off the registry at a far faster rate than new aircraft are currently produced. FAA and AOPA are aware of this sad fact and they react accordingly. Neither of them determines what fuel is available and how many tanks are at any FBO. That is a decision of the FBO owner and they already operate on very thin margins. Same old fifty-year old problem.

  9. GAMI took the initiative to identify the problem—spent a ton of money—came up with a solution—and submitted it for FAA approval—and the FAA DID SO. AFTER approving the STC, the FAA changed the rules!

    And the FAA wonders why people in the industry hold the FAA in such low regard?

  10. Perhaps the GAMI injector STC is itself detrimental to their cause. The original STC simply did what engine manufacturers should have been doing all along and after a time did. They simply matched the individual cylinder injector orifices to more closely match the actual airflow available to each cylinder. Nothing magic about that and some feel an STC to do that wasn’t even necessary. It’s akin to adjusting the mixture on your lawnmower. And the truth is that GAMI injectors really didn’t correct the root cause as the issue was the design of the air intake manifolds. It did make it better but their claims to safely operate the engine lean of peak as I recall wasn’t part of the STC and that became a very controversial subject. I will admit I’m now twenty years removed from those issues. I have no idea if GAMI has acquired any other STCs over the years that would improve their credibility but I can see why the FAA would treat them differently if that were the case.

    The STC approval process is in itself relatively easy. As FAA things go. You have to prove your gadget does no harm to the type certificate. Getting an STC for their injectors did not make them (GAMI) fuel experts in any way and hence the FAA would and should scrutinize them differently than a fuel refinery. But I agree the entire issue is of the FAA’s own making. There is really nothing that special in the operation of an aircraft engine over any other air-cooled engine. We all have been getting along just fine with our lawnmowers, ATVs, and whatever else burning that hated pump gas. You would think by now the engine manufacturers would have addressed any issues with updated internal parts just as the auto companies have. But as I recall, even with the highest-powered aircraft engines failures were seldom attributed to the fuel. More operational. Again, twenty years after leaving aviation I’m amazed this is still an unresolved issue. All IMHO of course.

  11. Makes me even more happy that I can just drive to any gas station and pump 90+ octane fuel into a tank to put in my plane. I only run 100ll when I HAVE TO. Ethanol has NO effect on my plane so I don’t even have to worry about that. My O-290 D2 will burn any fuel over 80 octane.I’m sure that when ever the powers that be make a decision there will be ONE fuel to replace 100LL and it will be at least $1 more a gallon than 100LL.

  12. I’m on board with the commenters who are saying that a drop-in replacement for 100LL is a pipe dream.
    It’s time to move to UL94 and be done.
    Yes, it will mean that some large-engine airplanes will need STCs and sometimes mods to burn the 94-octane. The FAA’s own certification processes are what makes that hard. Spend the money to develop those mods – it’s only a few engines – and make the STCs free. Heck, subsidize the parts.
    But let’s move on. We’ve been asking for 94 unleaded for decades. We keep getting told to wait for the mythical “one solution”. It’s not coming.

    • P.S. Once we do have 100UL (and now there are two) I expect it will be less than 2 years before there are environmental objections to the additives in them. And, we’ll also be back in the same situation we’ve been in, where the “secret sauce” is produced in one or two places and the fuel is a super-niche product.

      Between the technical challenges and environmental objections to new additives and the super-niche issue… it’s not coming.

  13. Regarding the difference between the PAFI/ASTM track and the STC track: How about an article from AvWeb or some feedback from some of the (at times) expert commentators on the two standards! If one standard is better, then why? What are the pros and cons? What kind of game is really being played with the GA (avgas) industry?
    Let’s get the facts out and forget politics and whether you might be a “D” or an “R” or even maybe not-partisan, which, by the way, is starting to be the most popular undeclared party we can attend!