EAGLE And GAMI: Not A Transparent Process


Big league pitcher Gaylord Perry was famous for his goofy, hard-to-hit Vaseline ball, but he was equally renowned for his anemic bat. That led Giants manager Alvin Dark to observe of Perry, “There’ll be a man on the moon before he hits a home run.” In the third inning of a game against the Dodgers, Claude Osteen grooved a fastball that Perry knocked over the fence in Candlestick Park. It was around 1:45 p.m. on July 20, 1969. Apollo 11 had touched down 30 minutes earlier in the Sea of Tranquility, although Neil Armstrong wouldn’t step off the LM for several hours more.

Were I to surrender to my black-hearted cynicism, I might be tempted to say we’ll be on Mars by the time the FAA’s PAFI program spits out an approved unleaded 100-octane fuel, but I don’t want to be too discouraging. And anyway, it’ll be a woman on Mars, so there’s that.

This week’s press conference with the FAA and EAGLE industry consortium brought this fuel thing back into focus reminding us all that the traditional way routing fuels through ASTM has still not yielded a suitable unleaded 100-octane gasoline. Just to bottom line it here, the FAA is at least now admitting there are two paths to getting to a new unleaded avgas, the FAA/fleet authorization/ASTM path and the STC or supplemental type certificate path. GAMI’s G100UL has already been approved under the latter process; nothing has yet made it through the former process.

The EAGLE consortium—for Eliminate Aviation Gasoline Lead Emissions—is an industry group meant to jolly things along, and PAFI—Piston Aviation Fuels Initiative—has been resurrected to do the testing. Two fuels are grinding their way through this process, one from Phillips and Afton, an additive company, and one from Lyondell Chemical/VP Racing. In that ideal world where Unicorns dance, these will emerge from the PAFI gauntlet as suitable aviation fuels and then move on to ASTM to be assigned an approved spec, like the D910 spec used for leaded avgas. Absolutely no over/under on how likely this is to happen soon or ever.

But one thing is clear: The industry really, really, really prefers the ASTM path and although the press conference gave lip service to the STC path, the participants made it clear an ASTM spec fuel will just be easier. To be fair, they’re not wrong. Try this thought test: If you could somehow wave a magic wand and remove the lead from a D910 fuel and have it retain its octane and call it D910a, problem solved. Everyone’s happy and everyone has the universally, internationally agreed to specification sheet to keep in the filing cabinet. They imagine—rightly or wrongly—that this assures quality and performance and minimizes legal liability. For airframers, engine builders and FBOs, the STC is less confidence inspiring because they’re less familiar with the process and apparently draw some comfort from having ASTM bless the fuel with a spec.

What this appears to be building up to, in my view, is an effort to stymy GAMI’s market development until the two other fuels can make it across the finish line. (Or, more generously, to have alternatives to G100UL in case it falters.) EAGLE sprang out the ground by surprise in November 2021 when it appeared that GAMI would finally get STC approval. The case against STCs takes the form of three phrases: transparency, we don’t know what’s in the fuel and we don’t know how it was tested. These reservations have been repeatedly raised when EAGLE has been involved with fuel updates at shows and events. Yet anyone with technical facility with patents can look up GAMI’s G100UL filing and get a good feel for what’s in the fuel. It does have a proprietary additive package, but that’s what makes it work. If the testing shows that it works, why is knowledge of the formulation relevant? (Works means it reliably has the octane, ages well, has acceptable distillation points and vapor pressure and materials compatibility.)

You don’t know what’s in a D910 fuel either, since you don’t know how good the base alkylate is or how much toluene or other aromatics are in the fuel. D910 is a manufacturing spec that specifies a range of certain chemical constituents that have been proven to work in aircraft piston engines. It’s not a recipe. Shell’s is different than Exxon’s which is different than Phillips’. In GAMI’s case, G100UL fuel will be delivered with a similar conformance spec sheet. It won’t have an ASTM logo. And yes, I get how that makes some people nervous.

The mystery of the testing is a curious one. GAMI has invited numerous key people to Ada, Oklahoma, and given over a day or two to run through the entire, FAA-approved and specified testing protocol for G100UL. Those folks had to sign an NDA, but got a nice barbeque lunch out of the deal. Of the major airframers, I think only Cirrus has had a persistent interest in doing this.

Cirrus has also done its own flight testing of G100UL. (Cirrus was not represented at the press conference. Piper, Textron and CubCrafters were.) The engine manufacturers have been mostly indifferent to the details of fuel development, with the exception of Lycoming’s former GM, Michael Kraft, who, before he moved up the ladder at Textron, spent several years on the brat and beer circuit reminding the industry that loving the problem would indeed make sure it wouldn’t get solved. That said, he wasn’t a fan of the STC path, either. 

The call for transparency gave me a good giggle. The PAFI process was maddeningly opaque. It was a black box. Despite the expenditure of north of $30 million in public funding, the FAA refused to answer any technical questions on the process or the findings and even GAMI and Swift have been unable to access the PAFI lessons learned in a meaningful way. I wonder if this will change in PAFI 2.0, but I doubt it. The federal regulations under which PAFI runs testing haven’t changed. The only thing in its favor is the timeline. EAGLE is pushing for a solution by 2030 and EPA has yet to issue lead prohibition rulemaking.

In the press conference, EAA’s Jack Pelton made a surprising statement by saying homebuilders can’t use STCs. Well, that’s not surprising because it’s true. They don’t have type certificates so a supplemental couldn’t apply. Pelton left the impression that to use an STC fuel, the builders would have to embark upon a test program of their own, but wouldn’t with an ASTM fuel. But in the real world, this doesn’t happen nor is it likely necessary because it’s not specified anywhere in the regulations. Builders are the manufacturers and they can write any specs a DAR will approve. This is the point of experimental aircraft. I asked EAA to clarify this and they replied that there’s currently no process to gather the data to show an STC fuel would be suitable for an E/A-B. I suspect we’ll hear from builders who don’t agree with that view.

I’m guessing that there’s a lot of not invented here going on. GAMI went with the STC process precisely because it was less cumbersome and mired in pitfalls than the fleet authorization path. And despite intransigent FAA resistance at every level, and resistance from the engine manufacturers, they improbably got the damn thing across the finish line, albeit it 13 years later. Vested interests resist going against the agreed upon flow and that’s what GAMI did. AOPA’s Mark Baker observed that if this fuel replacement was easy, we would have done it by now. In my experience of covering this for 30-plus years, it’s just that no one took it seriously enough to conduct research worthy of the word because there was no need to. The government could never pull it together enough to ban tetraethyl lead. GAMI has shown us that the fuel itself wasn’t so hard; the politics are the grind. Unknown is how much influence the extant refiners are exerting on this process. Avgas is a big margin product but not a big dollar market, but companies will protect what profits and market share they have. Market inertia, bureaucratic sclerosis and agency politics favor their efforts.

I think EAGLE and the alphabets are making a mistake by the not-so-subtle dissing of the STC approval method and, by association, G100UL. The fuel is out there. It has been through one of the most rigorous testing programs ever overseen by the Wichita ACO. It is, by all appearances, a suitable fuel for a 100LL replacement. It’s true that it doesn’t have to be and might not be the only one. Perhaps Phillips or Lyondell—or both—will develop better fuels that are less expensive to produce and sell. So be it. They should go forward with the support of the industry and GAMI deserves nothing less, not watery excuses about lack of testing and not knowing what’s in the fuel.     

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  1. The issue for GAMI is that right now G100UL is a solution in search of a problem. Leaded Avgas is legal, available, and has no promulgated date where it will no longer be legal to manufacture and supply.

    I am going to make myself really unpopular here and say the problem is actually the EPA. Paralysis by analysis will continue until there is a firm drop dead date for 100LL. When (if ?) that happens the regulatory log jam will get fixed because action will not be optional any longer.

    • Take out the EPA and any environmental or health concerns over 100LL, and what are the pros and cons of that fuel? Pro: It’s here now, runs in all existing engines, and is slightly lighter per gallon than unleaded equivalents. Cons: TEL is manufactured by a single provider, the lead causes fouling of spark plugs and contaminates oil (requiring more frequent oil changes).

      So there are actually plenty of problems with 100LL that have nothing to do with the environment or human health.

  2. By 2030 most all commercial aircraft will be Jet-A and the private owners of certified aircraft will be paying the price. Either they change their engines to a lower horsepower and use lesser octane or join the crowd and go turbine power.

    The wises thing for the private piston aircraft owner is to build or buy a Homebuilt aircraft. The FAA will never certify modern day fully electronic controlled engines that can burn autofuel. The majority of the certified aircraft are near the 50 year old mark. Time to let the antiques move on. By time the EAGLE and PAFI committees approve this drop-in 100UL fuel it will be $15 to $20 per gallon.

  3. Paul, thank you for pointing out the fallacy that ASTM somehow guarantees a “proper” avgas while GAMI’s STC is witchcraft, not worthy of the flying public’s trust. As you point out, D910 does not mean all producers create an identical fuel, just one that meets a consistent specification. None of the major refiners will tell you exactly what ingredients are in their fuel, just that it meets the D910 spec. How is this any different than GAMI’s proprietary additive package that has been well tested to meet the various FAA fuel requirements? Several years ago, when PAFI 1.0 was in full swing, I had the opportunity to sit at a dinner table next to George Braley. I asked him why GAMI did not enter the PAFI competition. He said that, based on how the FAA structured the process, it was virtually guaranteed to fail in producing a useful result and he felt that going it alone gave him more freedom to test and make changes to arrive at a useful end product. With PAFI, the formulation you came in with could not be changed, which defeats the purpose of a science-based process. I agree with you that the not-invented-here syndrome has played a part in the FAA’s continual obstruction of GAMI’s process, and EAGLE is just another roadblock set up in the hopes that some magic unleaded avgas will appear from the usual suspects and save the day. Maybe it will, but if (when) the EPA delivers a finding of endangerment, it is possible that the one producer of TEL then calls it quits. In that case we, and the FAA, will be in a real pickle without GAMI’s UL100. As for EAA’s concern about homebuilders not having access to an STC, I suspect GAMI would be willing to sell them the engine STC, providing they are using a Lycoming or Continental engine. After all, both manufacturers have said that G100UL will work in any of their spark ignition engines now, or previously, in production. If the builders are using another engine, they are probably using mogas anyway.

    • I’m puzzled by the statements about homebuilts and STCs. Homebuilts do not have type certificates to supplement. Want to burn GAMI fuel (or gas from Costco for that matter)? Put yourself (back) into Phase I, do your testing, write your placards and documentation accordingly.

  4. I’m hoping GAMI will get its G100UL in the field in California this summer and start the process of its public retail rollout. That will put more pressure on the industry to get it available more broadly, not just were LL sales are banned.

  5. Another irony in this EAGLE/ASTM mess is that GAMI’s G100UL is to my knowledge the only aviation gasoline that has an FAA-approved specification and QC program, thanks to the STC process. As Paul B points out, the cries of lack of transparency, ring hollow here. No 100LL avgas has an FAA-approved spec, only consensus legacy ASTM. I can assure you, that were 100LL being developed today, competitor companies would not be able to agree on an ASTM specification for it for their own economic interests.

    Also, thank you Paul for pointing out that among the engine and airframe companies, only Cirrus has accepted the invitation of GAMI to actually come to Ada for a full technical briefing and demonstration of the fuel, the testing process, and a full performance disclosure in their engine test cell. For what they describe as an existential issue, you would think due diligence would demand to at least a first hand investigation (and some OK BBQ).

    With a proven solution at hand, this is feeling more idealogical, political, and ego driven than rational or scientific. Reminds me of many other bureaucratic dysfunctions. Meanwhile, as the alphabets argue and posture and procrastinate, GA aircraft owners and pilots continue in UL avgas purgatory.

    Personally, as a E/A-B builder/manufacturer, the limitations section of my POH for my RV-14 with Lycoming 390 engine specifies any minimum 100-octane avgas as an approved fuel for my aircraft. No STC required.

  6. As an EAA member, I too was surprised by Jack Pelton’s comment on an STC’ed fuel for experimental aircraft. While technically correct, STCs do not apply to non-certificated aircraft, the business plan for Swift and GAMI require buying the STC to in order to purchase their fuel at the delivery point. Perhaps a better process for GAMI/SWIFT use for E/AB aircraft is to require a one-time purchase of a “use-license” to buy their fuel. Cost would be based on the same engine HP rating system use for aircraft requiring an STC and would get your tail number in their purchase authorization system. My Honda powered E/AB does not like 100LL and it is almost impossible to find MOGAS or any UL fuel at airports in the southeast. Fortunately, non-ethanol 93UL is widely in costal Florida even though you have to haul to the airport.

    As to fixing the problem, I expect it will take an Act of Congress to force the FAA off the EAGLE/PAFI path. They could start with simply declaring G100UL as an approved replacement fuel for any application requiring D910 rated fuel and waiving any fuel-based liability associated with using it. Or they could use the EAGLE funding line in the FY24-FY30 FAA budget to buy the G100UL technical data from GAMI and publish it as the ASTM specification. The only way you can fix the bureaucrats is to take away their money and authority.

    • I was blown away by Pelton’s position. I already quit AOPA after being a member since 84, over their refusal to correct their 100LL page that incorrectly stated that you need an STC to use Swift UL94. You don’t, if you have a grade 80 engine.

    • Art Wesley (below) has the right idea, that I have expressed previously about having to buy STCs for different fuels, but I think you have the right idea about an act of Congress to mandate G100UL across the board without an STC. Anyone else would be free to develop a competitor if they can meet the same standards. Despite the AOPA and EAA bragging about their role in getting BasicMed through the FAA, I saw no significant progress until it was mandated by Congress. Unleaded fuel has been going on a lot longer with very little more progress. Where is Senator Inhoffe when we need him?

  7. I agree with “[email protected] “. The FAA should negotiate with GAMI and buy all the rights to G100UL. Publish the specs and tell the refiners to start making it. Get rid of the STC process but make sure to pay GAMI what they deserve… which is a lot! Do that and we could be rid of 100LL by 2025; not by maybe 2030.

    • I second your motion. But I still would like a UL 94 path, where the feds build the infrastructure, as they owe the entire country for dragging their feet on this. UL91 has been live in Europe for a very long time.

    • Sounds good. Maybe you could do like the Tesla owner who got tired of range anxiety and began carrying a portable gasoline generator in his car to recharge the batteries if he ever got stuck away from a charging station. 😎

  8. While G100UL is the only fuel that provides a solution to the leaded fuel issue, the present STC process is acceptable. But there will, eventually, be competition. Right now, Swift UL fuels work in my 230 HP 80 octane engine and G100UL will. So does alcohol free mogas (leaded or unleaded) (Petersen STC) and has given me over 3700 hours of trouble free operation and long exceeded overhaul intervals. The cons: I have to find ETOH free fuel, and I have to cart it to my base airport who discontinued it years ago for unexplained reasons. I paid to use mogas. Now, if I travel to California I might have to buy a GAMI stc. Swift runs in my 80 octane engine under the ASTM spec. but if I needed their higher octane, then a second STC. and when FuFuFAA Fuel company gets the next STC on their fuel, now my third, fourth, … , STCs at $230-460 or more a pop, just to buy 50 gallons of gas? Or my fuel planning becomes a nightmare, and a programming nightmare for Airnav.com and fleet managers and flying clubs.

    As a longtime STC mogas user, which allows any alcohol free mogas which meets octane specs and also covers Swift Fuels 91UL, but not GAMI’s, I can see it for a broad class of fuels, but GAMI has taken it in a new and alarming direction. Imagine if you had to buy STC equivalents to buy automotive fuel from Exxon-Mobil, Marathon, BP, Getty, and Shell to fuel your car where you needed to, and a separate collection for your SUV and your pickup?

    The STC is untenable for equipment users and anti-competitive for fuel producers. Monopolists always have a rational for maintaining a monopoly and the end users always have to pay if the monopolists’ product is mandated.

    Fuel is a commodity. Attempting to make it into a part or component is an unreasonable approach. That is why the EAGLE/PAFI/etc is continuing and should continue, but in a more open source form, with much more transparency and reasonable flexibility, and independent from the current government grant style review processes where preconceived prejudices may rule.

    We do need a requirement for any potential standard to be publicly available through NIST so that we can all review standards relied upon by the government without having to pay a private agent large sums to view the standard, but to enter the STC process into the mix is guaranteed to create an expensive mess and render the whole process untenable. If GAMI were to take the approach of licensing its intellectual properties, we would, through the sales process chain, pay GAMI for its work probably on an per gallon used cost, but the fuel would remain competitively priced or other entrants would enter the market.

  9. Paul B., excuse my ignorance, but just who is it that establishes the ASTM fuel specification? The FAA? The oil companies? ASTM is an independent entity that is not a part of the FAA or any other government agency, but I don’t know the mechanics of getting a specification approved. It would seem to me that drawing up a new spec that has the same performance requirements of D-910 for unleaded fuels should be a no-brainer since it does not specify the chemical formula except to prohibit certain materials that would be deleterious to an airplane’s fuel system.