Sleepwalking To 100UL


In yet another milepost in the galactically slow train wreck that is finding a replacement for lead-spiked avgas, the EPA has finally announced its intent to declare leaded fuel environmentally hazardous. And this time, says EPA, we’re serious so all you FAA footdraggers better pay attention. No, really. We mean it. But wait, hold up. What the press release headline said was this, exactly: “EPA to Evaluate Whether Lead Emissions from Piston-Engine Aircraft Endanger Human Health and Welfare.” The waffle word here is “whether.” If the answer is no, no endangerment, then what? Or was this just sloppy prose? Try not to think about it.

Let me again apologize profusely for my unbridled cynicism, but I’ve been covering this unleaded fuel thing for a long time and can’t help but believe that by the time we get this well and truly done, your car will have its own hydrogen fusion reactor and Elon Musk will be opening his second hotel on Mars. But seriously, where are we now on this interminable regulatory grind?

The EPA’s announcement on Wednesday puts a kind of mushy marker down saying the agency intends to issue formal findings by the end of 2022 and from that will emerge specific rulemaking sometime in 2023, the details of which won’t be known until the ink is dry on the documents. Presumably, the FAA and industry have now been put on notice that tetraethyl lead will no longer be permitted as the excellent octane enhancer it has been for so many years. But will that be a date certain that’s soon or another distant deadline to allow the industry yet more developmental time because, after all, 40 years is just not that long? Or will the rules allow some of the half steps proposed in the National Academies of Sciences, Engineering, and Medicine Transportation Research Board report that appeared last year? That august body was tasked by Congress to untangle this avgas problem and make recommendations. Read it for yourself here, but warning: No easy, clean fixes are to be found.

I wouldn’t take a bet on any of this, but my guess is, given the FAA’s recent panicked reorganization of what sort of looks like the moribund Piston Aviation Fuels Initiative, this time we might actually blunder toward a solution of some kind. But nothing is certain, including the EPA’s own findings. In a summary report issued in February 2020, the EPA itself said this of research into hazards posed by leaded aviation fuel: “The two reports are based on the best available, recent data, and use sound analytical methods, but they do not draw definitive conclusions about actual lead levels or risk (AVweb emphasis) and should not be used to evaluate attainment of the lead NAAQS.” That acronym stands for National Ambient Air Quality Standard and applies accepted standards for various pollutants, including lead. EPA research does suggest airborne lead concentration around some airports may approach or exceed NAAQS limits. In other words, despite the uncertainty, EPA is pushing ahead with the potential endangerment finding. Or so it appears.

This is not an argument for retaining lead, by the way. We should have eliminated it years ago, in my view. Only lack of commitment from regulators and industry kept that from happening. Recall that in 2013, the FAA formed the PAFI group with the goal of shepherding a fleetwide unleaded fuel to the market by 2018. Never happened. PAFI was the classic governmental machinery into which money was poured, but nothing emerged. Then, out of the blue, it seemed to rise from the dead with a surprise meeting last November whose goal was, in classic FAA speak, to “invite industry to work in collaboration with government/ FAA toward a lead-free future for aviation gasoline.” I thought we had been doing that since 2013. One task for the November meeting was this: “Socialize Initial Framework with Stakeholder Community and Obtain Feedback/ Collaboration.” There’s a full-throat call to arms if ever there were one.

I’m not sure where this process is going because Shell, once thought to be a leading contender, exited PAFI, Phillips never entered it and the only company to produce a certified fuel, General Aviation Modifications Inc., was never in it, either. Swift also bailed. We don’t know if there are other candidates, but if there are, they better get busy. Despite the EPA’s waffle—and “whether” is a waffle—it could drop the rulemaking hammer eliminating further use of lead. And suddenly, there would be no solution. Except there is. GAMI’s G100UL is approved for hundreds of engines and the list is being expanded. Through Avfuel, it has already graduated to the production and distribution phase, although AVfuel told us at AirVenture in July that this will be a slow, deliberate process.

There’s still some pushback against the fuel STC idea, both within the FAA and the industry. The agency is hung up on a fleetwide approval process which literally requires an act of Congress, since the language has to appear in the FAA’s annual reauthorization. To be fair, it’s not unreasonable to pursue other options even if G100UL is in the bag. GAMI says G100UL will cost more to produce and sell, although whether a 60 or 80 cent price delta matters is open to conjecture. There’s nothing wrong with having another choice in the market to promote price competition. Price notwithstanding, we should all cheer an unleaded future. No fouled spark plugs, cleaner oil and cylinders and none of the nasty lead salts that promote corrosion and crankcase gunking. Whether lower maintenance bills will offset higher fuel cost is further conjecture, but the trend is promising.

We have, in the aviation press, generally assumed that a two-fuel ecosystem—low octane for the low to modest performers and 100-octane for the Cirrus crowd—wasn’t viable. But in this blog, I found more support for the two-fuel idea than I imagined. If force feeding Cherokee drivers with 100-octane they don’t want or need gets them sufficiently up in arms, maybe a two-fuel market is realistic. In its UL94 avgas, Swift has the product, it’s competitively priced with 100LL and users seem to like it. Unfortunately, it’s manufactured in Indiana in low volume. If demand were sufficient, I suspect Swift could find more geographically favorable production sites.

That this may hinge on what the EPA does 24 months from now might be a little disquieting. But in the world of leaded avgas replacement, we should all be used to that by now. The only certain thing is uncertainty.  

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  1. The writing is on the way and 100LL is suffering a death by a thousand cuts. Whether its individual state (like CA) or cities or companies that mandate the end of 100LL, the trickle has begun. That process is only going one way, and 100LL will slowly die out. Between municipalities that don’t like airports, the green lobby, or companies/schools that want to appear green, each time one switches it furthers the death of 100LL. I’ll be glad to see it go, tetraethyl lead is a nasty poison that has super nasty effects in people.

  2. 100UL is the end state, the only question is how we get there. The reality is that any contest that pits the environmental lobby against private aviation is a sure loser for GA.

    This is the time for everyone to pull together and articulate a plan to get there from here.

  3. It is interesting to learn that credit is given to several US companies about unleaded AVGAS.
    The truth is that Hjelmco Oil in Sweden already 40 years ago introduced unleaded grade 80 AVGAS with nationwide distribution and this fuel was used also by the Swedish Air-force.
    In years 1991, i.e. 30 years ago Hjelmco introduced grade 91/96UL which the same year was approved by the Swedish Civial Aviation Authority. The grade UL94 circulating in the US is an attemp to copy the sucessful AVGAS Hjelmco 91/96UL® which today is the most used AVGAS in Sweden. Already in the year of 2006 (yes more than 15 years ago) Hjelmco introduced the unleaded grade 100 UL which at the same time was tested and evaluated by an other European Civil Aviation Authority . That fuel meets ASTM AVGAS standard D910 parameters (100 LL standard) in all respects except for energy content (gives 1-2 % potential higher fuel consumption). In order to get this fuel certified Hjelmco spent 10! (yes ten) years in the ASTM to get the active component certified to be included in an aviation gasoline meeting ASTM standards. This component now has a current US standard.
    In the Dec 2021 unleaded AVGAS meeting with the industry arranged by the FAA Hjelmco Oil was banned by the FAA to participate in spite of a formal written request from Hjelmco.
    The 100 UL AVGAS invented by Hjelmco:s Lars Hjelmberg carries several fresh US patents, as well as patents in Canada and many more countries in the world. The patents are also owned by major world leading international AVGAS oil companies. You can Google yourself to find them.
    It is interesting to see how uncomplete information to the US public can be and sadly the potential censorship ? that evidently is existing.

    • Lars, combined with Art Wesley ‘s note that follows, has hit the nail on the head without actually saying so. They both detail solutions already in place that are being ignored by industry and the FAA. Not that the FAA has ever been a leader in innovation of course, they are far better in their roadblock mode. Another fine example of that is the 5G squabble currently going on.

      What both men say, without putting it into words, is that this is a clear case of “Not Invented Here”. The FAA banned participation by Lar’s company in the meeting in Dec. The FAA has tons of old rules about innovation in modifying the engines as needed to meet currently necessity. Art is right, the old 225 slant 6 Chrysler motor was beast but it worked, ALWAYS! Had three cars with one and my Dad’s orchard spray rig ran on one all summer long. year in and year out… with no maintenance beyond oil changes and a tune up every three or four years.

      It is simply beyond belief that the various manufacturers can’t come up with solutions to this problem with the myriad of electronics and sensors available today. Look at auto engines, those of us from “way back then” find very little that is recognizable under the hood anymore yet they work fine, produce good power and mileage, and seem to require less “fixin'”. It is long since past time for the public to get on the government’s case about the stupidity of the various “lettered” waste of time and money agencies that are sucking up our hard earned tax dollars and producing no results worth publishing on the rolls of 4″ X 4″ paper found in every home today…

  4. There are a number of things that can be done right now. One is alcohol free mogas availability. Overnight this will reduce the use of 100LL. My airport refuses to carry it so I tanker it in. It is available at the pump in premium grades 91/93, although my STC says it’ll run fine on 80/87. Some airports I regularly fly to carry it. One switched back from Swift to mogas.

    Gas isn’t the only problem. I’d love to replace my carbureted engine with FI, but then I can’t use mogas.
    Yet, Dodge produces a 3.6L V6 burning 87 unleaded fuel that produces 300 HP in a 227 cid engine that weighs pretty much less than my 470 ci engine producing 230 hp. Yes, car motors are different, with different operating parameters, but the efficiency gains in motor engines since the phase out of leaded mogas in 1971 are phenomenal. A Dodge 6.4L/390 CID weighs 500 lbs and produces 480 hp.

    How do they do it? With EFI and electronic engine controls. My old ’65 Plymouth wagon with the slant 6 got 22 mpg and 145 HP at a massive 445 lbs. It also knocked (we called it pinging) when the timing was set to spec with leaded mogas. The FAA has only two electronic ignition systems STCs available. One does not permit timing variability the other does not allow the dual mags to be replaced. Add a knock sensor, and a more sophisticated ECM refit and I suspect most aircraft engines could use high octane alcohol free mogas, provided ignition controls could predict and limit operating ranges of our aircraft engines. Add an EFI retrofit and I’d bet we could do more with injected engines and make 100LL or its substitutes obsolete.

    If we could fast track ignition system and fuel distribution modernization in exchange for aviation fuel that costs (in my area) $2.00/gallon less and improve burn rates from 12 – 16 gph to 9-10 gph, at a cost of conversion of about $5000/engine the fuel savings will pay the cost in 3-6 years in fuel savings alone.

    • There are modernized engines right now unfortunately because of certification and liability costs they aren’t $5000 they are $60,000-$100,000. There was a push to add FADEC about 20 years ago and the mods were around $5000 then. The idea that we can get fuel modernization now for $5000 per engine seems ludicrous. What is more likely to happen is what happened in Europe where most people fly 100hp LSA and everyone who has enough money moves to turbine and everything in-between just goes away. The people with the lobbying money in GA all fly turbine engine aircraft anyway

      • European light aircraft generally either use Rotaxes running on Mogas, or diesels running on jet fuel.
        New aircraft with piston engines requiring leaded fuel simply don’t sell in Europe.
        There is no earthly reason someone cannot produce a fadec for common aircraft engines that will let them run on premium Mogas; the only problem is certification, and a US legal system which preys on innovation.
        Most privately owned piston aircraft will run happily on 91 octane Mogas already, it is only the few firebreathing engines that need 100 Octane, and there are products available for them.

    • Art – you are so right. Some 20 years ago Hjelmco tested its 91/96UL® AVGAS with GAMI in the GAMI engine test-cell in Oklahoma City and with one of the most demanding octane wise engine, a Lycoming TIO 540 100 LL engine from a Piper Navajo. All parameters were in the red and the test run was observed by people from AOPA and the engine did not knock. An article in size 1 by 1 inch? was published in the AOPA Pilot magazine if I remember it right. The engine was equipped with the GAMI PRISM system, a system that not yet has seen the market and which adjusts the ingition on the engine to avoid knocks.
      By the way – Paul indicates if I understand it right? he now might think dual AVGAS fuels would be a solution? Hjelmco took this decision already 40 years ago so as the leading AVGAS company in Scandinavia we provide both AVGAS types with nation-wide distribution where the market so asks for it. The reasons: unleaded Hjelmco 91/96UL® is so much cheaper to produce than 100LL so why should the ordinary Piper Cherokee owner or Cessna owner pay one dollar more per gallon for the 100LL fuel he does not need and further will contaminate his engine. Lycoming engines with TBO of 2000 hours typically operate 3000 hours on the Hjelmco unleaded AVGAS. With 30 years on the market for the 91/96 UL®– the statistics is there.

      But the train has already left the station in the US. Talking about an unleaded AVGAS 100 is history. The Hjelmco 100UL AVGAS invented some 15 years ago is a BIO-AVGAS. The future is not an unleaded AVGAS but a BIO-unleaded AVGAS and the US is still waiting for approvals of non-bio products when train already has left the station.

      • “The engine was equipped with the GAMI PRISM system, a system that not yet has seen the market and which adjusts the ingition on the engine to avoid knocks.”

        How does the system know that a knock is coming so that the ignition timing can be adjusted before a knock occurs?

        Most knock sensors detect knocking and then adjust the timing. Problem being that once the sensor has detected knocking in some cases it might be just a tad too late.

        • The GAMI PRISM system monitors cylinder pressure in real time through a port in specially made spark plugs, if I remember correctly. It then retards timing to reduce the cylinder pressure to a level which won’t detonate. Knock sensors haven’t been adapted to air cooled opposed engines, to my knowledge, because they are just too noisy.

          There are EFI systems available for experimental aircraft that adjust timing and fuel delivery using a fully user programmable map. The user can choose to retard the timing from the advanced setting by a certain number of degrees based on MAP every 100 RPM and save it to the map. There is also a feature to bump the timing advance by however much the user programs when running LOP. If the new map causes it to run hot meaning possible detonation, he can revert to the previous map and tweak it again later. This setup could certainly be used to tune an engine for unleaded fuel and could probably allow it to run on pretty much any reasonable octane.

  5. Hi Paul,
    Pumped a bunch of purple 115/145 back in the day. Burned a few tons of red 80 then, flying for a living, green 100/130. Now blue 100. Still use a little bit of blue, here in retirement, in my old Piper Cub. Recon I don’t much care the cost per gallon any more: Ya gona fly this thing or not?

    At 78 yo . . . will I live to actually see the demise of tetraethyl lead? Hmm . . . wondering what color 100UL is.

  6. Doesn’t this draw a parallel to the COVID-19 vaccine? It takes 7-10 years to develop a drug but somehow a vaccine emerged within 18 months +\-

    If the FAA were to drop the hammer I bet we’d have 2-3 alternatives. Until push comes to shove no one is incented to do anything.

    • I’d like to think so but COVID vaccine was needed by a majority of the population. Unleaded 100 octane avgas is need by a small minority of the population. As another poster said we might end up with low compression and turbine engines in service. The other scenario is that the 100ul alternative will be priced significantly higher than current 100LL (and I don’t mean .60-.80 cents per gallon).

    • You have it so backwards. It wasn’t the government demanding a vaccine that got it done. It was a bunch of determined scientists who did it simultaneously despite the government and because of the government. Truly, they did it because it was their calling, their dream, but also for reasons such as pride, money, and recognition. They did it in a weekend, but that’s misleading because they had been becoming ready to do so for many years. They were operating like a business which constantly seeks to solve a problem, create a product, sell that product, and repeat the process.

      In the end though, they were held up by a bunch of “alphabets” who had bad incentives and culture. Some of that was mitigated because some “fools” with no idea how wrong it was wrote huge checks to have production start before the vaccines were approved. I call them fools because there was every reason for government employees not to do that, but they did it anyway. Bless them.

      I don’t care which side of the aisle people come from, if they cannot see the problem is that there is too much government and complexity in the scenario, there is something intrinsically wrong with them. Most likely, it’s having spent too much of their lives dealing with needless levels of government bureaucracy.

      All of this occurs while we are supposed to be a democracy run by the people. People who have not the time nor the ability to understand their own government any longer.

      There is a lot of room for reasonable disagreement, but I think two things should be generally agreed upon first. One, an immediate carve out for no ethanol fuel marketed to non automotive users should be enacted. And two, there should be a general agreement that the current situation is one created by our government which should be resolved at the expense of our government, and with a goal that the resolution be one that does not lead to a repeat in the future.

      We are stuck with the fuel and engines available because the government has created a regime where the market cannot function freely enough to offer choices. All the proof one should need is that the government is currently involved in choosing the fuel which will be the solution. We will burn it in engines which are positively antiquated in design to fly planes which are decades old because of the certification regime which is designed to protect the flying public from unsafe operators of piston aircraft for hire. Exactly what percent of our fleet is used to fly paying passengers?

      It’s all insane. We know better. The regulation needs to be minimal. The choices need to be restricted only by necessary boundaries rather than by proscription. These are the ways we get most of our nice things. This is The Who’s our country has led the world for decades. We defeated fascism and communism using these ways. We should not now be living under a statist dystopia.

    • What exactly does the STC really do? Repay the company doing the test? If the government is going to choose the winner, they sure as hell ought to pay for it. If they come up with a standard, then walk away, then the STC makes more sense. I suspect the testing is beyond reasonable though.

  7. Avgas is not hurting kids, it’s our terrible schools which are ranked worst among industrialized nations.
    The, when the kids are dismissed from school, they go home and smoke dope and play video games. (OK, flight sim is OK)

  8. Lead is bad for people and for engines; the footdragging on unleaded AVGAS is nonsensical.
    As one comment above points out, Sweden has had unleaded 100 Octane fuel for years; guess they are smarter than Americans who cannot figure out how to do it.

  9. All I know is that I’m glad I didn’t sell the original -E2D 80 octane burning engine from my 172. IF necessary, I could rebuild it and then use MOGAS.

    Just tonight, I took an IA renewal webinar hour by Eagle Fuel cells. They pointed out that even 100LL formulation has changed in recent years and is — itself — now more detrimental to rubber and other like products then when it was first introduced.

    I saw a meme that fits the comments about the alphabet soup organizations lack of proactivity. It showed two slices of bread on END with the mean hanging over the small edges. The comment was, “If Gov’t came up with a sandwich making standard.” (sigh)

    • You are correct, Klaus, that there are alternatives in the experimental world that could make life simpler for we muggles in the certified world. But, the people who use them are usually individuals who understand what they are designing and will adhere to any unique operating requirements of those systems. The FAA, for all its warts, feels they have to stupid proof everything so that we muggles don’t kill ourselves when we forget to control the mixture properly or some other misstep. Engine designers don’t help much either due to liability concerns. There are small signs of hope though. They now allow electronic ignition with adjustable timing and other items on the NORSEE list that have make life better and more affordable. In government, change comes slowly.

  10. This is not a joke. They are going to develop this endangerment thing, throw it at the wall, and it is going to stick. Nothing will trump the health endangerment of lead and kids. The environmental laws already on the books were passed decades ago with a great deal more political resistance than will be seen here. Big energy, auto, and oil companies could not out lobby it in the 1970s. Fighting for the survival of 100LL is not a winnable fight. The leaded gas battle was lost in the 70s even when it had a great deal more political horsepower than it will now. They still lost.

    Today, there is nothing but a 0.01% of the population and their airplanes which the general public already feels is an unreasonable endangerment despite the fuel. They will ground thousands of airplanes if they don’t come up with an unleaded alternative. The FAA is going to have to become more flexible and approve some of these unleaded alternatives.

    I have been expecting the shoe to drop on this one for a long time. AOPA has been mostly silent on it. They need to get engaged and get the FAA to approve unleaded fuel alternatives. And start providing MOGAS everywhere. Many planes can use MOGAS but airports dont want to deal with it. They will be forced to change.

    Tetraethyl lead is only manufactured by one company in the world. The environmentalist could sue them for making it. Or some environmental magnet like Soros or Bill Gates to buy it and shut it down. 100LL is untenable by many counts.

    • Lead is not great, but there is no current health risk associated with 100LL. Period. Full Stop.

      Of course the unhinged and politicos don’t care about reality because “the know they are right” and “think of the children”.

    • “AOPA needs to get engaged on this!” Surely you jest, Kenalanlewis? That’s an oxymoron. EAA might do something and then AOPA will claim credit for it … in between selling wine in their wine club and printing magazines full of turbine aircraft ads.

  11. It is correct that the Swedes have a 100UL fuel that they have used for years. But, as Larry noted above, changing the chemical composition of our current 100LL is more complicated than just giving it enough octane value to not knock under full power. It also has to be compatible with the sealants and rubbers in fuel tanks, hoses, carburetor floats and gaskets that are used in legacy aircraft. It also has to pass standards for aging, vapor pressure and a whole host of other issues that make a new formulation much more difficult. Again, the government doesn’t help because there are several octane enhancers that the EPA says are not permitted for use (benzene, MTBE, etc.). The current 100LL is produced from mostly common refinery products that are mass produced, and therefore relatively inexpensive. (I emphasize “relatively”) Both the Swift and GAMI substitute fuels use chemical compounds made in specialty chemical operations in relatively limited quantities. That makes them more expensive to produce, thus more expensive for the final fuel. I don’t know how much the Swedish 100UL costs, but I’ll bet it is much more than the $4-$5 a gallon range we see here for 100LL. Yes, there are alternative fuels available, but none are cheap or easy to produce. Like Larry’s government designed sandwich, having the government involved rarely makes the process any better, or less expensive. And, unless there is a good profit motive involved, private companies aren’t likely to be interested either. The problem may look simple, but it is far from it.

    • John … during the hourlong webinar by Eagle Fuel cells, they were saying that 100LL USED to be very very stable and could be left for long periods of time in airplanes, et al. I knew that so at my hangar in WI, I’d fill my various small engine vehicles with the stuff prior to leaving for the winter half of the year. More recently, I’ve noticed that the fuel isn’t that way any longer … supporting the comments I heard in the webinar about the formulation changing in recent years. I’m not a fuels engineer so I can’t specifically enunciate what the difference is other than … there IS a difference. I shudder to think of what’ll happen if airplanes that’re parked for long periods in winter start having stale fuel issues suddenly … especially if some new concoction is blessed as usable. Lets hope the same FAA engineers who allowed MCAS to occur or designed the KC-46A boom camera system don’t get involve.

      So one part of Government is doing one thing while at another, they’re doing something totally different. Can you spell 5G ?

      • Sadly, Larry, there are many government agencies that work at cross purposes. 5G is a good, current example, but there are so many more. It seems to be in the nature of government. In the FAA’s case, they not only fight with other agencies, but they also are up to their eyeballs with internal infighting and poor communications. The PAFI program is an excellent example of that. Several years ago I spoke with George Braley of GAMI about why they avoided the PAFI program and went the STC route instead. He said that GAMI was not interested in competing with other companies, just working to find a formula that met all the standards. WIth the STC route, he just had to work with engine manufacturers and get their approval for the final product. Then GAMI could petition the FAA for STC approval, already having the support of Continental and Lycoming. He correctly predicted that PAFI would ultimately fail, which it did when both Shell and Swift pulled out in frustration. We didn’t talk about fuel stability in detail, but George did say that it was an issue they were addressing with an additive package. You are right to be concerned about stability and what effect southern heat or northern cold could have on the fuel. When (not if) leaded fuel is banned, I hope we have a gradual phase in of whichever unleaded fuel is chosen so that problems like long term stability can be explored in real world conditions. Unfortunately I am not optimistic of that happening, because gradual is not in the EPA’s dictionary.

  12. I know I’ve said too much already, but…

    Why can’t the government promise no fuel taxes for ten (?) years on replacement fuels meeting the needs? It’s much simpler than these tax rebates they use on electric cars which also pay no taxes in an often vain attempt to reduce pollution.

    Have the companies send in the usual paperwork, but reduce the tax to zero. We can monitor the adoption rate and retain the statistical data while the public pays for the public benefits. The FAA gets funded by reporting the lost tax revenue and getting a check from the program.

    Why not?