GAMI Crosses The Finish Line


When George Braly and Tim Roehl embarked upon the should-not-have-been-so-hard task of developing a 100-octane unleaded fuel, I was still a young man. Pretty much 11 years younger. That’s how long it took for the FAA to stop dragging its feet, cease erecting bureaucratic barriers and refrain from changing the rules after every test proposal. But as of Tuesday, the deed is done. General Aviation Modifications Inc. got its STC for G100 fuel.

Now the interesting part begins. How to integrate a fuel into a broad system that kind of stumbles along on an uncertain will by the oil companies to continue supplying a leaded fuel when a perfectly suitable unleaded alternative is available. And how the two fuels will coexist peacefully until the unleaded variety can displace the leaded version. The trigger point turns on two factors. What regulators will do about finally stamping out lead and what the major oils now producing leaded fuel decide to do.

Last week, I asked the EPA where they are with the finding of endangerment that would finally declare lead to be a hazard worthy of rulemaking to bar its use. The answer: ongoing work, no timeline. Ditto in Europe, which is generally more stringent about such things. I don’t see anything certain about the timeline there, either. But it may not matter. With a suitable unleaded fuel available, the momentum may shift because of the inevitably of leaded fuel being phased out. I can’t imagine lead will still be in fuels five years from now. But then I couldn’t imagine it would take 11 years to get a workable lead-free fuel developed. And it really took more than 30, since this work began in the late 1980s. Dozens of alternatives were tried, none worked. As long as the EPA’s lead dispensation for GA existed, the work was barely serious.

The major oils have been backing out of avgas production in slow motion. Chevron used to make it at its Salt Lake City refinery, but stopped when the equipment reached end of life. It still makes it in Richmond, California, but who knows for how much longer. By history and tradition, Phillips seems to be the most committed to aviation fuels and is reportedly developing a 100-octane product of its own. We have no reliable information on this, so it might as well not exist. Exxon is still in the game. Who knows if they want to bail out of messing with dangerously toxic lead.

As refinery products go, avgas is profitable, but not much. Demand is about 150 million gallons a year and Paul Millner, who spent a career in the refinery business including avgas production, estimates the total profit in avgas hovers around $50 million a year and is probably in graceful decline. This could mean that some of these companies will be happy to scrap the lead shacks and convert to producing G100 under license from GAMI. As Braly told me, if that does or doesn’t happen, GAMI has engaged Avfuel to produce and distribute G100. Since it’s a blended component fuel consisting of available alkylate and a readily manufacturable additive package, this should be technically doable, although ‘twixt cup and lip there are potential stumbles. One is that if states and/or cities begin prohibiting leaded fuel before a credible production system is in place, demand could outstrip supply. And suppliers and oil companies have routinely engaged in counter-competitive contracts to exclude certain fuels from a presence on the airport. These companies tend to have well-staffed legal departments always looking for court challenges.

I’m trying to look on the bright side, though. The STC at least offers a glimmer of hope that there is finally a 100-octane alternative and that airplanes that require it, won’t find themselves beached if the push against lead pollution reaches critical mass. I would love to have parked an HD-recording fly on the wall in FAA HQ to see what finally broke this loose. I can’t help but wonder if it was a sense of panic that it would finally be revealed that the reason it took this long is not that some miraculous chemical had to be discovered or there was some demon lurking in the dark corner of the detonation envelope or that some obscure federal regulation gummed up the works, but because certain factions in the FAA tried to prevent it, aided and abetted by certain factions in the GA industry itself.

But it’s done now. Let’s just move forward and see what happens.

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  1. The technique of approval by way of an STC is still problematic for a drop-in or blended product. For example, even if GAMI gives away the STC approval for free, how do they ensure that their fuel product isn’t sold to an airplane that doesn’t have the STC “installed”? I know George says he can print out the STC on the fuel receipt, but installation of an STC on an aircraft isn’t something a pilot can do. Even a garden variety A&P can’t do it. A major alteration needs to be accomplished by an IA with a form 337.

    Or perhaps this is one of those cases where we decide that the presence of an STC doesn’t mean something is a major alteration? (Rosen sun visors anybody?) If it’s not a major alteration (if it is a minor alteration) then we’re back to only needing an A&P to sign it off.

    If we’re saying it’s not an alteration at all, then do we care what airplanes are covered by the STC in the first place?

    It’s a slippery slope.

    • You know, this GAMI fuel is kind of like the Covid vaccines. Either it works, or it doesn’t.
      STCs for this are like masks for the vaccinated. It’s all about control; not “the science.”

      • Agreed that this fuel either works or it doesn’t so the need for an STC is moot. But this fact is poorly served by a bogus analogy. All analogies no matter how clever break down at some point along the way. This one didn’t have a chance from the git go.

        • Well,..
          – it isn’t that simple, ‘works’ is somewhat variable, various deficiencies/sensitivities can occur in engines due to fuels, including coking and deposits.
          – the question is how to convince other people, especially the gummint, otherwise you must have a neat research project into which you sunk a pile of money.

          • And vaccines against SARS2 in fact do not always work and have side effects.

            Some are significantly less effective than others, supposedly the case with vaccines rushed out by Communist China and Russia.

            Side effects vary, such as the blood clots with one brand. (Rare but does occur.)

    • Keep two things in mind about STCs:
      – they are well known, one-off/field approvals are not
      – the FAA forced George to gat an STC in order to sell matched sets of fuel nozzles, to even stress on cylinders.

      Never mind he had not altered any parts, just was reselling them in sets selected by flow testing.
      Never mind that SOP in aviation for bearings and tiny light bulbs for cockpits were selected. (In those cases only ones within tight tolerance were kept, the rejects were sold to other users.) Bearings were tested for vibration at low rpm, a measure of non-uniformity of balls/rollers. Bulbs were aged first – a good idea for incandescent bulbs, then selected for brightness.

      FAA was so constipated despite George’s engineer-lawyer skills that the debate rose to the gutless Administrator, who convinced George to obtain an STC.

      • I once debated for four hours with an individual in Seattle MIDO about permits for flight testing. Smart guy, usually helpful, but he had a hangup.

        And that MIDO office was ignoring HQ policy that clarified.

        That was in the era when FAA had issued a permit for a prototype airplane to fly from Oregon to OSH but it never arrived. FAA was probably sued.

        One outcome was a standard policy of limiting permits to 500 nm radius. So one day I find myself directing an avionics flight test out of the Seattle area, in a good DC8-73. One item in the testing was to be performed in clear air at altitude, for extra safety.

        But weather was deteriorating in the region, so we decided to go to Great Falls MT if necessary. Oh! that’s somewhat over 500nm. Fortunately weather improved so we stayed local. (Do that test over the ocean for extra safety, the rest of the testing was at low altitude.)

        In making sure the permit covered what we needed, we did not think about the limit, we had no need to go far and didn’t think that weather would deteriorate. But FAA were silly in not differentiating between a proven fast airplane with modest modifications and an experimental category slow airplane.

  2. There’s already states that will increase the taxes or outlaw leaded fuel by year’s end. This transition will be sooner and faster then people are reporting. As for STCs, most aircraft that eligible for autofuel have acquired an STC with no problem that I’m aware of. Why should this be any different?

  3. This is yet another illustration that the FAA really doesn’t want to bother with General Avation, but they can’t bring themselves to get their foot off the neck of GA. That’s why I refer to them as the “Friendly Airline Agency”. In their perfect world, GA would not exist and they would only have to deal with airlines and manufacturers like Boeing and Airbus. No one at the FAA has any incentive to take a chance on approving something new that could come back to hurt their career path. Also, in our economics driven world, the engine manufacturers have no incentive to change their engine designs to adapt to unleaded fuels. Continental and Lycoming could/should have seen this coming over 30 years ago – plenty of time to develop engines and ignition systems capable of accommodating lower octane fuels. But jumping over the many hurdles of the FAA – both in terms of time and expense – was not worth it when they could continue selling the existing engines that people were willing to buy. I congratulate George and the GAMI team for sticking to their guns and producing tangible results. It will be interesting to see how the flying public accepts it.

  4. There is zero evidence that 100LL use is causing health issues. There is zero measurable evidence that piston GA affects the global climate.

    What we have here are unelected “regulators” who are squashing things they just don’t like and don’t think we should be doing. It’s a mad world.

    • The problem with the unleaded push is more the politicians, like Hanoi John Kerry, and media regurgitating claims of eco-activists.

      There may be more gummint employees who are more collectivist than the average outside of the gummint, but there is clearly a push by politicians and agencies other than FAA.

  5. There is no minimum safe level of environmental lead. Even small amounts can have devastating impacts on children. More and more environmental activists are documenting residual lead near GA airports.

    Banning lead from fuel is a no brainer for politicians as there is no down side from their POV. I am frankly surprised that leaded Avgas has survived this long and so now the challenge is going to be an orderly transition to a UL 100 without local supply outages during the change over.

    The thing I am afraid of is that GAMI has a monopoly on UL Avgas. The overall market is probably not big enough to encourage serious competition and so I think keeping Avgas prices reasonable is going to be a real issue.

  6. More fundamentally it is a distribution problem.

    Beyond the basic underlying g cost of fuel, the two big variables in fuel cost at the pump are taxes and transport. Where is the refinery?

    Where is the terminal holding inventory?

    How far will trucks have to carry it?

    Who will pay that price at the pump?

    I have also wondered, frankly, if lead serves to reduce detonation at high power settings, would merely adjusting timing and derating engines a bit solve the problem?

    Force=mass X acceleration.

    A slight loss of force (with other appropriate adjustments) would seem viable, …certification and bureaucracy aside.

    The power to weight of my Cessna 337 is plenty. If I lost a bit of power, physics would impose slightly longer takeoff run, a bit less payload, slower climb etc.

    I realize not all aircraft have excess power to spare, but consider the alternative.

    With all the variables, at the end of the day what counts is delivered thrust, yes? Which can be measured in pounds.

    Anyone out there interested in tying a giant fish scale to a tree and the tail of an airplane, to give us some numbers for resultant pounds of thrust as a function of power settings?

    • No need for a big fish scale. Just find an airport with a long runway with no obstructions near the end. Then try taking off with less than full throttle. How much less? Try it at 95% power. Then 90% and so on until you find the minimum acceptable to get safely airborne. Oh, and be sure to do this on a hot summer day with high density altitude. You migh be surprised how quickly your plane’s performance degrades.

    • And when one your Skymaster engines resigns, what then?

      I assume you have a twin for a reason.

  7. No minimum safe level of lead? Compared to leaded paint and lead pipes, both of which are now rare as the proverbial hen’s teeth, all other general sources of lead ingestion by children are truly infinitesimal. Given lead is a naturally occurring element present in the Earth’s “environment”, at what point do you stop? You can carry any good idea to excess.

    • “:You can carry any good idea to excess.”

      Indeed, which is the problem with bureaucrats like FAA, and with eco-activists who have no perspective in their endless push.

      The EPA under POTUS Obama was actively trying to silence people skeptical of its climate catastrophism push.

      Aviation is under attack by anti-human activists in any case.

  8. OK; Lead is bad for people; if you don’t understand of want to believe that; fine; Lead is also bad for your engine!
    Lead shortens valve life; that nonsense that it “lubricates” valves is propaganda which is long since disproved.
    Engines operated on unleaded fuel have much longer cylinder life; 50 percent more in the cases I know best.

    Most GA engines could easily operate on 91 octane unleaded; think premium mogas with no ethanol (Shell)
    Many do with great happiness.
    The problem is the firebreathing engines that actually need 100 Octane; this is driving the rest of the market.
    The crazy thing is, that the engine companies could have developed electronic engine controls for their current engines, making them perfectly capable of operating on unleaded fuel; long ago.
    Why didn’t they do that?
    Likely the American Legal System which implies that if you change something, it was previously defective; cue the lawyers!
    Current car piston engines operate very high compression on ordinary pump gas; this is more difficult but not impossible on AirCooled engines.
    Our engines have primitively low compression ratios; it can be done.
    In any case; in a few years, as gasoline for cars disappears, it will be come a more expensive boutique product for aircraft;
    Better to get yourself a diesel airplane, because jet fuel will be around a lot longer; sustainable jet fuel is coming fast.

    • “The crazy thing is, that the engine companies could have developed electronic engine controls for their current engines, making them perfectly capable of operating on unleaded fuel; long ago.”

      This is not really true. Aerosance/Continental tried it with what became the PowerLink system. Aerosance’s intent was to eliminate the need for 100-octane by manipulating timing to control detonation. They couldn’t make it work. Lycoming tried with the IE2 system. Similar results. The engine still needs 100-octane.

      One reason, I was told, is that acoustic knock sensors don’t work well enough on these engines to respond quickly to detected knock. Also certification challenges.

      • Interesting, thankyou Paul. Certainly air-cooled piston engines are structurally different from liquid-cooled automotive engines.

        Not many people hotrodding puff-cooled VW automotive engines I suppose, though they were used in Porsches and 1981 VW air-cooled engines have computer control. (VW switched to liquid cooled engines in 1982 for its Vanagon line, identifiable by a grill at bottom of front and a label something like Wasserboxer, boxer describing horizontally opposed cylinders.)