Losing Lead Doesn’t Drive Fuel Development, Preserving The Status Quo Does


I was talking with Alan Klapmeier the other week about a topic we both hold, if not near and dear, then certainly in the top five reasons why general aviation remains such a frustrating backwater. The story he told me related directly to the slow-motion train wreck we’re watching as the industry stumbles toward finding an unleaded replacement for 100LL avgas. I would urge you to keep it in mind as you read news reports about “efforts” to find a replacement and how hard the FAA is working with “industry stakeholders” to find a solution.

But first, a word on the plumbing here. The stories in the AVweb news well are what we call straight news. Something happens, we describe it and report it as faithfully as possible, bereft of any opinion or comment. But, as the grizzled city editor once told the cub reporter, “we don’t print the truth, we print what people tell us.” In this space, the AVweb blog, we’re free to comment on what people say is going on between the lines but which they won’t commit to on-the-record comments for various reasons related to politics, economics and interpersonal relationships. This is a backdoor way of saying that what we report in the news well, quotes and all, is often tainted by industry efforts to have something appear to be true merely to support a desired narrative. That’s hardly unique to aviation.

Klapmeier’s story is relevant in that it shows how hidebound aviation can be. People who participate in it—that’s you and me—are generally conservative and resistant to change and many of the companies in the industry will say and do things to keep it that way. When Klapmeier was doing early work on development of the Cirrus, he gave a presentation about avionics and what he thought the industry needed going forward. It was obviously sophisticated glass. Someone in the audience asked a lot of curious questions and after the presentation, approached Klapmeier for more, leading him to conclude the company was interested in developing such things. But no, said the avionics person, he wanted to make sure such things were never built and needed to know how to achieve that.

Cut and paste this on top of the GAMI G100UL fuel project and things come into focus. First, some indisputable facts. There is now no government mandate for unleaded aviation fuel. The EPA is expected to issue a finding of endangerment against lead sometime this year, but it hasn’t happened yet. And even when it does, if it does, the timeline for rule making is at least three years out, if not longer. This is one reason the FAA’s EAGLE program can dawdle along for eight more years sleepwalking toward a possible solution. A handful of refineries now make 100LL and it is a profitable, if minor, product for them. Business inertia being a thing, there is no obvious reason why these refiners want to either stop making 100LL or rush into making an unleaded 100-octane fuel that could very likely cost more to manufacture and possibly have lower margin. In other words, an early migration to unleaded fuel is counter interest for them.

Aviation gasoline is, at best, a flat market. It has been gracefully declining since after World War II. In 1992—30 years ago—the volume was 860,000 gallons a day. Now, it may be stabilizing at about 500,000 gallons a day, but maybe less. It seems unlikely to grow. Phillips, Chevron, Exxon and Shell divvy up this market, but Phillips seems to have the largest chunk of it. Developing a new unleaded fuel is more expensive than you might imagine. Paul Millner, who worked in the refinery business for many years, estimates it might require $20 to $30 million. By oil company standards, that’s not a staggering investment, but it’s not a very attractive one, either, when the market is small and fractured. If I were a refinery manager, I’d probably say no to that project.

The airframers and engine companies obviously have a vested interest in a stable fuel supply. But what they absolutely, positively do not want is to get bogged down in a lot of expensive testing to approve these fuels for myriad engine and airframe combinations. They would prefer someone wave a magic wand at a fuel that is instantly approved for every piston engine. The possessor of that wand is the FAA and basically, by the power vested in the administrator by congress, the administrator can approve the process by which a fuel attains so-called fleet authorization—not the fuel itself, the process. That’s why the airframers and the engine makers are smiling signatories to EAGLE. It’s OPM—other people’s money—toward an approved fuel. They may also believe the EAGLE testing program will be more competent and thorough than GAMI’s was and, in any case, will have the full faith of the government behind it. This ignores, of course, that GAMI’s test program went on for 13 years and was minutely supervised and approved by the FAA. From what we can tell, the Wichita Aircraft Certification Office left no stone unturned in overseeing the GAMI testing, but the details remain opaque to the outside world.

In the middle of all this are the alphabets—AOPA, EAA, GAMA, NBAA. All of these organizations are supportive of EAGLE because that’s what the FAA desires and, through Congress, the agency will be the source of OPM to ever so slowly and uncertainly stagger toward approved fuels. GAMA has openly disparaged G100UL by suggesting liability concerns, the need for refining it under license and the inability to know the composition of the fuel. GAMA, of course, doesn’t represent pilots or owners, but aircraft manufacturers. In any case, the alphabets support EAGLE and are, at best, neutral toward GAMI’s STC approach to an approved fuel. They may be reluctant to publicly endorse G100UL for fear of getting sideways with the FAA.

The FAA’s intransigence in the final approval of the G100UL STC may be the result of a multitude of factors. As far as we know, the Wichita ACO did a thorough job of overseeing the test program and sent a complete package to FAA headquarters where it has languished unapproved since March. Resistance to approval may be related to the mess the FAA made in overseeing the Boeing 737 MAX project—bureaucratic gun shyness, if you will. Also, the agency may want to siphon more money from Congress to support EAGLE over the next eight years in an environment where the EPA still hasn’t legislated against lead in aviation fuel, where there is no groundswell of demand for unleaded gas and where 100LL is still available. It’s not known if the oil companies who have a vested interest in the status quo exert enough influence on the FAA’s bureaucratic minutiae to stymie the approval, but their resistance doesn’t help. There could be other factors we don’t know about.

In the Technical Advisory Board review of the STC, the issue of detonation testing was raised. Evidently, the TAB questioned how the GAMI testing was done, even though it was completed under a method carefully reviewed by the FAA itself, including what expertise was available from FAA HQ. This review is not an unreasonable thing to do, given the stakes. However, having done it, FAA HQ will now need to lead the Wichita ACO line by line, data point by data point through the process to reveal where they went wrong. Detonation testing may have been a dark art once, but it isn’t now. It doesn’t take Merlin the Magician to figure it out.

If questions about detonation are other than a smokescreen to simply delay the STC approval and preserve the status quo, the FAA will have to produce hard data on the right way to do detonation testing. Thus far, it has not and has refused to explain why or why the approval remains in limbo. The TAB raised other issues, but without agreement on detonation protocol, the others don’t matter. As it proceeds with EAGLE, the FAA will have to reinvent this wheel and I’m sure we’ll be writing stories about how complicated and difficult this process is, all of which serve maintaining the status quo.

Ideally, in a world unconstrained by reality, you can imagine a testing program far more ambitious than GAMI’s STC work. It could include thousands of hours of detonation testing in test cells and fleet trials over a year or two in various operations and climates. Maybe three or four fuels could be trialed and compared. The FAA would have to fund this because it’s very unlikely that industry will. And honestly, is this problem so difficult to require much less justify this kind of effort and expenditure? Personally, call me skeptical. To insist that it does strikes me as just more loving the problem, as former Lycoming general manager Michael Kraft was fond of saying. He, by the way, wanted the FAA involved but opposed fuel approval by STC.

If the GAMI STC were approved, thus rattling the status quo, GAMI and Avfuel, which will manufacture and distribute G100UL, face the daunting challenge of selling an unleaded fuel in a market that doesn’t require it and which will be more expensive. The fuel would probably gain traction in California and among pockets of early adopters elsewhere, but this is far from a certainty. A profitable, going operation is by no means assured but the risk will be shouldered by GAMI and Avfuel, not by the FAA nor backed by taxpayer dollars. In my view, the sales rap for unleaded fuel doesn’t relate to health concerns, but cleaner running engines with less plug and valve fouling and maybe longer TBOs.

As EAGLE unfolds, we will duly cover all the meetings assuring us that it is on track to approve a fuel or fuels by the end of 2030. This will give the impression that the problem is so difficult that a massively funded, multi-year program is necessary to really solve this problem, thus allowing you to believe the GAMI STC approach is somehow inadequate. Could this, in fact be true? In my view, the best and only way to find out is to approve the STC and get G100UL in the field. It is supported by a good-faith testing program buttressed by a mountain of FAA-approved data. But there’s nothing like real world experience to reveal the cracks in a concept and if G100UL fuel isn’t what GAMI says it is and falls short, then it will either get fixed or it will fail. Anyone who thinks about this honestly should accept that this is a possibility, but that’s simply not a valid reason to withhold approval. Yes, there’s risk here. But that will be true of whatever Shell, Phillips, Swift or anyone else comes up with. Fear of failure is not justification for blocking progress in favor of the status quo.

Neither is the claim that a license-refined fuel would create an anti-competitive monopoly. Nothing is stopping other companies from entering this space other than lack of will. If G100UL gets into the market and finds success, the status quo will wobble and this appears to be the last thing FAA, the established fuel suppliers and industry stakeholders want, at least for the next eight years. I would suggest you filter all you hear and read about EAGLE through that lens.

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  1. What I would like to know is, what was the genesis of EAGLE? Who or what was it that made the case that PAFI was a failure but EAGLE will be a success? Was it industry, the FAA, or something else? It wouldn’t surprise me if the creation of EAGLE had something to do with the then-apparent imminent STC approval of GAMI’s G100UL, and that there’s some connection to the delay in the EPA’s expected lead fuel endangerment finding.

    • It shouldn’t surprise you because that very well could be true. Recall that last summer at AirVenture, the limited STCs for G100UL were approved. Then out of nowhere in a big rush around November, EAGLE appeared. It looked very much like the FAA organizing an effort to stymy an expansion of the GAMI STC and enlisting the rest of the industry to help.

      That fits with the FAA sitting on the approval for no apparent reason. PAFI was likely also a response to GAMI’s early STC work.

  2. “The EPA still hasn’t legislated against lead in aviation fuel.”

    And, as SCOTUS recently pointed out, the EPA CANNOT LEGISLATE ANYTHING. It is an agency of the Executive Branch of government. ONLY the Congress can LEGISLATE ANYTHING.

    ‘Bout time that somebody read the damned Constitution.

    • Well, EPA sure thinks it can do things.
      Does it have for example Congressional approval to label carbon dioxide as a very bad substance?

      A court did whack EPA back recently on something, but I expect the eco-bleeps in EPA will keep trying.

  3. AvGas is an insignificant market.
    Lead from AvGas is even less of a significant concern.
    Why can’t legislative people understand that any action they do will neither help the market nor save the planet. Sometimes it’s actually better if you don’t “do something”.

    • The earth only has 12 yrs before everything dies (at least that’s what we are told). This issue is moot unless we all agree to change how we live by returning to the pre-industrial age and dedicate half our income to new taxes for “green” energy while the ruling class upgrade to bigger jets and buy more mansions around the world.

      • It’s working. Every summer tell them it’s getting hotter. I acknowledge that the solution here is upgrading from being a loser GA pilot to flying a private jet, if only for the stable supply of JET-A but I’m curious why 12 years rather than something more ominous like 13. Is it a multiple of election cycles or the length of time it takes for the public to stop questioning the basis of a lie? Kids spoon fed this bunk will now be voters? A dozen – just to make it sound like some imperialist measurement? Hmm, you sure about 12 – like exactly? Either way I still look forward to the end of the world in 2030, just like I did in Y2K. Fear aside, we have something to look forward to, something I dream about it when I’m deep in the throttle – watching California burn to the ground. Fire up those engines boys, were gonna cleanse the planet.

  4. The Chinese, who own Continental, Superior Air Parts (which makes parts for Lycoming engines), Cirrus, Diamond Aircraft, Mooney and a host of other GA suppliers, will not lift a finger in solving the leaded fuel problem. They simply want to have a stranglehold over the free world General Aviation industry. If the EPA threatens to shut down leaded fuel users, the Chinese will threaten to shut down GA.
    The real solution is development of reasonably priced Jet A piston engines, or even better, cheap turboprops.

    • As the “manufacturer” of my RV-14, I establish the operating limitations for it. In my case, the POH limitations specifically requires 100-octane avgas, either 100LL or G100UL. So, to my knowledge, it is the first aircraft to approve the use of GAMI G100UL. Now, where can I buy some?

  5. The switch to Mo gas should have happened long ago.
    But like the AM air band radios that should have gone digital 20 years ago… I don’t see anyone that is interested in increasing the cost of flying by inventing new and better equipment.

  6. Paul,
    I read some time ago that electronic ignition systems from manufacturers like Sure Fly, Smooth Power, Electroair and others could be a tremendously effective detonation prevention system and thus help allow fuels without lead (and even current 100ll) to be used without the risk of engine damage.
    While I know the FAA is not going to foot the bill for we owners to install those systems, would it make sense, in your opinion and mathematical formulas, to divert the FAA’s spending to helping certify those systems to work on unleaded fuels?

    As an owner, I don’t love the idea of having to replace a magneto or two in my one airplane (I know the fleet owners won’t love this either). I did not love the idea of spending money on an ADS-B compliant transponder or WAAS upgrade for my panel-mount GPS – but I have reaped some benefits in improved traffic awareness and being able to fly precision approaches at airports inaccessible in the past.

    These electronic solution manufacturers tout reduced fuel use and other performance benefits – which be a long-term benefit to help recover the investment…
    Interested in your thoughts as always!

    • There are great detonation detection systems available. Problem is that detonation has to occur first so that it can be detected. The first instance of detonation can be so severe as to cause engine damage. By the time an engine control unit gets word of detonation, it may be too late.

    • Except the benefits weren’t there. This ground is pretty well trod. Almost 30 years ago, Aerosance developed what became the Continental Powerlink system. Electronic ignition, pulsed fuel injection and rudimentary diagnostics. They certified the system for both aftermarket and OEM use.


      Again, conservative attitudes of both customers and OEMs resulted in almost no adoption. For high output engines, 100-octane was still required and this system otherwise just didn’t do much for the additional cost, weight and complexity.

      Lycoming’s IE2 engine has done better, with a launch customer in the Tecnam P2012. But it still requires 100-octane fuel. So not much help there. The engine is getting good reviews in the 2012.

      There’s also Air Plains’ Inpulse water injection system. Works well, but is kind of stillborn for lack of an AML list. Basically applies to only two airframes and one is an agplane. If it were expanded, the $12,000 price might come down quite a bit. It would allow burning mogas and/or UL94. But it would also require serious and persistent marketing, which has not been done. It would be a big investment to make it work, but it might find traction.

      • The Inpulse ADI system is approved for Beech Barons, Cessna 210’s and the Cessna 188. It’s not been widely adopted because it’s expensive and old tech, but it works. You can shave 12 or 13 octane points off an engine using this system. If the FAA had spent half the time and money on mods like this instead of a drop in replacement, the problem would be solved by now.

    • Good point.

      Modern high-performance cars use electronics and detonation sensors to accommodate regular gasoline, though they perform better on high octane.

      Detonation sensors may or may not be easily retrofitted, the automobile examples I have come across were designed in at the factory (Chrysler 3.5L morphing of V6, and Corvette). I don’t know what hot rodders are doing, much equipment is available in general.)

  7. When the first unleaded fuel is approved, I expect to see an explosion of local government restrictions eliminating 100LL similar to what happened in SoCal. Local governments have a means of social engineering through taxation so unleaded fuel will most likely become the only fuel available at airports by simply taxing 100LL into oblivion. Does anyone really believe a local government doesn’t see this as a money-making opportunity?

    The suppliers of 100LL could see their market rapidly evaporate and have to make changes, hence their institutional roadblock to G100UL approval. The overseers would have no need for EAGLE, nor its associated funding for the next 8 years. GAMI is in the unenviable position of having an eloquent solution to a problem that those profiting from the problem don’t want fixed.

    I thought the end of GA would happen when 80/87, 91/96, 100/130, and 115/145 went away, but I was wrong. I’m looking at the other side of that coin now, but this time it could hurt us more deeply if we’re not prepared.

    • “by simply taxing 100LL into oblivion”

      Local government can try that. But aviation fuel taxes are a Federal issue. If a LOCAL tax is levied then the entire funds collected must be returned to aviation. Otherwise, it is revenue diversion.

      Been there, seen it attempted, it fails if correctly challenged.

  8. Perhaps there is no chemical or substance known to man that can take the place of lead so as to maintain a given octane level in gasoline. Or which is not toxic in and of itself or which is not cost prohibitive. Perhaps a solution is being sought when there is none available.

  9. To paraphrase a long published poster, even when there’s an obvious solution there’s good money to be made by prolonging a problem.

    Is it too much to hope for SOMEBODY in government to have an attack of good sense and stop this messing around?

  10. In October 2019, AHIA issued a report on engine durability in R22 and R44 helicopters in which avgas of various aromatic content, distributed in Australia, was determined to be causal to reliability issues in Lycoming engines. This was disputed by CASA and its independant findings in December 2020. At the same time, Lycoming published Service Letter L282 stating that a “slight increase in exhaust gas temperature” was found using fuels of higher aromatic content. The stated increase is considered “negligible.” Regardless, Robinson Helicopter revised its POH regarding hot weather operations and cooldown rates. They also encourage bulk fuel facilities to ensure their avgas meets all correct fuel specifications.
    Is it any wonder no one wants to own this dog?

  11. there is also the basic problem that bureaucrats (which the FAA has many ) do not get rewarded for doing something good and taking a risk. they get fired if something goes wrong. Therefore it is far safer for his/her job for the government employee to say no and or work to push the responsibility off on someone else.

    I know this personally. just try to get a modern electronic ignition approved on a seabee which has a breaker ignition off a 48 Ford pickup or similiar. the modern stuff is far more reliable and safer but it is not “legal”

    we need to reward people for trying to make things better.

  12. at one time there was a proposal in a plan by the Faa for an owner to put his old aircraft into experimental (like Sweden does) so it could be easily upgraded. As a Seabee owner I do not want to make the choice between legal and safe

    by the way what ever happened to that proposal? I have been unable to ever find out what happened.

  13. I’m a bit confused as to the situation with AVFuel and GAMI’s agreement and how it would work. They would need the existing refiners to make the fuel under contract correct? So the refiners would necessarily have to know what they are making. Am I wrong?

    Is there some justifiable concern that the introduction of G100UL into the system would cause some players to exit the market? I always assumed GAMI would be collecting a royalty on every gallon, but letting all the existing players continue to supply the market.

    • When you say “existing” refiners, if you’re thinking just the ones that now make leaded avgas, the answer is no. It could be any refiner capable of doing the blending. Avfuel will essentially be the manufacturer and distributor, which they have done before and are doing with SAF, a new expanding market.

      The refiner needs high-quality aviation alkylate probably shipped in by rail, then adds GAMI’s proprietary octane package to produce the finished fuel for distribution. An existing avgas refiner could do this to if they see it of interest.

      • I find it hard to believe that a refinery could have an ingredient in their system which they do not know the ingredients of. Interesting.

        So, let’s say the Phillips plant down the road is now producing Avgas, they could switch by buying GAMI’s product, and sell that to the local airport? What’s their reason for caring then, which fuel they make? Is it more competition?

        • Oil companies horsetrade on licensed products all the time. Not a new thing at all.

          “What’s their reason for caring then, which fuel they make?”

          Their reason for caring is that leaded fuel is a profitable product for them, they’re dominant in the market and protected from new entrants by the barrier of installing lead handling and the lack of suitable base alkylate capabality. I imagine they would be quite happy to continue that status quo for as long as they can.

          • Okay, I guess I haven’t got the full picture. Im still a bit unconvinced. I keep hearing how our refineries are in need of reconfiguring and that no one wants to try because of the red tape and lawsuits. So I’m making assumptions, but I don’t have the full lay of the land.

            Thanks for the responses.

  14. As I see it, the problem isn’t lead or no lead, the problem is avgas. As Paul B. notes, the volume sold has been declining for years. Many governments are hostile to gas in general and the oil companies are disincentivized to add refinery capacity, period. The FAA now wants to approve an unleaded fuel by 2030. Meanwhile, California has already legislated a ban on gas-powered vehicles by 2035, just five years later. This is only small-fry GA’s problem, as the airlines and the global warming elite will likely continue to truck around on Jet A for much longer.

    The right time to have switched to an unleaded fuel replacement for 100LL was 10 or 20 years ago. In today’s political environment, I believe James C.’s comment above is correct: a number of locations will mandate an immediate switch to an FCC-blessed no-lead fuel for various political reasons. However, it’s quite possible few of the oil companies will want to manufacture that new fuel, and no-lead could become no-fuel at all for the GA fleet. I wonder how much of the FAA’s kick-the-can down the road intransigence comes from fear of that possibility.

  15. Assuming Paul’s inferences are correct, the infuriating thing is not the competition among divergent interests to prevail over others; that’s the American marketplace at its best, both spurring innovation and rewarding efficiency. The infuriating thing is the involvement of government, meddling in the market to hobble winners and boost losers. Congress and the courts should have a close look at FAA’s meddling in the civil aviation fuels market(s). FAA’s involvement appears to have precious little to do with its safety mandate and everything to do with manipulating markets to please monied and connected interests.

  16. Consider this: The bulk of AvWeb pilot/readers will have quit flying before there is a firm decision or a sound distribution system for a universal unleaded fuel, so it is now and for the foreseeable future, this discussion is moot point.

  17. Why don’t we call the status quo what it is: Stupid.

    Think about it–Look at the hourly cost to fly. Two biggest components: Fuel and Engine Reserve.

    Why is there the big cost delta between pump gas (which has a higher tax btw) and 100LL? Most–and yes, I get not ALL–of that cost premium is to deliver a fuel with performance specifications that ARE NOT REQUIRED for most GA Aircraft today. Yes, I get there are high performance engines that require every bit of the technical specifications that 100LL provides; but everyone else is paying for a fuel that delivers performance they don’t need to complete THEIR mission with. The many are subsidizing the few when it comes to GA fuel.

    There is a reason that the flight schools using LSA’s that can run on E10 are filling up their tanks at costco.

    Second, there is is real opportunity to meaningfully increase the TBO (or on condition) life of engines by avoiding leaded fuel. There is a reason that ROTAX engines, which can even run on E10, require more frequent fuel change intervals when running on 100LL vs. unleaded.

    Between the two factors, I can see a single easily having a ~$30/hr lower operating cost.

    • Nearly 70% of GA fleet can safely burn 94 Octane Avgas such as UL94 from Swift Fuels. It is preferred by Rotax, endorsed by Lycoming but is not available everywhere. And most GA aircraft other than LSA’s can’t use Mogas with ethanol without some concerns about fuel system components or other specs. In Calif, ALL Mogas has some ethanol in it, so going to Costco isn’t an easy option, except for Experimental owners…

  18. I know I’m peeing into the wind, but what bugs me about this whole issue is that, as far as I know, there is no data to support the fact that lead in aircraft exhaust poses any risks to humans in the vicinity of airports. In fact, I remember reading something about the ambient lead found in the vicinity of one of the California airports was no higher than the ambient lead found away from the airport; and that there were other sources (I don’t remember what) which released more lead into the air. Sure lead is bad stuff, it’s toxic; but don’t drink it, bathe in it, snort your aircraft exhaust, or let your toddlers chew on the window sills of your hundred year old house. So, where I can I read the study about how much lead aircraft are pumping into the atmosphere? Like I said, peeing into the wind.

    • We’re based at Reid Hillview Airport in San Jose, CA, where the dreaded “Lead Study” was used to justify outlawing the sale of 100LL and to “expedite closure of the airport” so that the county could offer the land to real estate developers. The EPA studied the air at the airport in 2020 to model airborne lead for every other airport in the US, as they did at Santa Monica in 2010 . That study with monitoring devices did not find elevated levels beyond the airport boundaries. The County’s study in 2021 found slightly elevated levels in children’s blood by a business professor who correlated data from other studies but didn’t measure anything. And the county’s own data showed several higher levels in zip codes nowhere near an airport, tied to paint, plumbing, legacy lead from cars and lead arsenate insecticides used through the county for years. The most comprehensive rebuttal study is:
      https://calpilots.org/wp-content/uploads/2022/03/Response-to-EPA-regarding-Lead-Final-20220228-2.pdf Finally, in 2022 the County spent another $70K actually testing the soil near and around the airport, and found lead levels well within safe levels prescribed by the EPA and consistent with or lower than other lead levels in soil throughout the county…

  19. As a plane owner at one of those Calif. airports where sales of 100LL are banned, I’ve been using Swift’s UL94 for a year, and it is a great (if more expensive..) replacement. No problems.. What PAFI and now EAGLE are struggling with is that the refiners want an easy to make lead-free replacement without having to pay royalties. And they aren’t working on it themselves.. They want the government to develop and “guarantee” it and then mandate it so it can be rolled out smoothly and efficiently. Both GAMI and Swift (which also has a viable unleaded 100 octane fuel in “testing”) have based their business models on licenses, STC’s and royalties for their proprietary formulas. The FAA and Industry groups seem to dislike the royalty/proprietary formula model as well, and would prefer a competition of at least two viable options, with the winner getting a plaque but no pennies per gallon for their development. PAFI collapsed because the only non-proprietary formula left was too expensive to produce and more harmful than the lead in 100LL. And so we wait. For those whose airports are going to see protesters and see 100LL banned over the next few years, hopefully Swift’s UL94 will work in your plane…

  20. Lead is not good for engines or people.
    There is no earthly reason for the ridiculous delays in approving the new fuel.
    Unless; Lycoming has no alternate engines that don’t need AVGAS?
    Continental has diesels to replace most categories of gas engines at the next overhaul cycle; just need the STC’s.
    Much of the GA fleet could use existing AVGAS without the lead; those engines that don’t really need 100 octane.
    For those fire breathing engines that really need the 100 Octane, they probably spend a fortune on overhauls regularly anyway; give them five years to switch to Jet A burning diesels; they will save on fuel thereafter.

  21. I remember the day that 100/130 was replaced with 100LL. I do not remember any committees discussing what seemed to be an overnight replacement to 100LL. 115/145 was discontinued with very little public input and 80/87 just priced itself away. 8 years from now, less then 15% of the GA fleet will require 100 octane and the industry will just discontinue 100 octane everything. Besides, we’ll all be flying eUnicorns powered by rainbow fuel in 8 years.

    • By tradition, by common law, and by the absolute refusal of pinheaded politicians to reject their life-long fantasies for common sense fantasies, there can be no selling of rainbow fuel without having a verified “no harm, no fowl” Santa Clause in the agreement with the Eagle Fairie Queen. The fuel prophets will determine what profits go to whom (or what), with everyone else just receiving a tolkien.
      We just have to hope that a wise LL Leader such as Saint Jose rises up to lead us up.

  22. Like all difficult problems things have to get worse before they can get better. Until there is a crisis there will be the usual paralysis by analysis on the part of all involved parties.

    I predict it will take actual dry Avgas tanks and stranded airplanes before there is any meaningful progress.

  23. Paul-

    Thanks for continuing to write definitive articles on the development of no-lead fuels for high performance aircraft engines.

    I agree that the real benefit may not be so much for the environment and public health, but for aircraft owners. Getting the lead out will help reduce lead salt deposits on exhaust valves which can cause valves to stick and damage valve trains, etc. Getting the lead out may allow us to increase the time between oil changes, perhaps in addition to some other oil refinements as has been discussed in Aviation Consumer.

    I have noticed a lot of variability in the amount of lead in my oil measured by mass spectroscopy. There’s been no difference in oil added (1 quart per 25 hours), time the oil is in use (25 hours), or difference in leaning (on the ground and in flight I am LOP, I climb ROP in my normally-aspirated, IO-550 with altitude compensating fuel pump). I just got results back from AvLab that were 6 times what it was 6 months ago and 3 times what it was 3 months ago. This suggests to me there is a lot of variance in how much lead there is in the fuel and that could raise the concentration to the point of increasing the risk of valve deposits and valve sticking.

    Cleaner engines, as discussed above, may, with experience, eventually lead to higher TBOs or greater comfort with running past the manufacturer’s recommended TBO. That is worth paying a little more per gallon if it comes true, not only for less down time and lower cost, but possibly greater engine reliability and somewhat lower risk of engine failure related to valve problems.

    I have personally had a valve stick on my IO-550, which is supposed to be relatively rare compared to Lycomings. I ended up having all my valve guides reamed. The top of my piston struck the valve and my push rod was very slightly bent. Mass spectroscopy on the valve deposits showed lead bromides and other lead salts. Until we get lead-free fuels, it is important to run your engine at high enough temperatures so the lead scavenger in aviation fuel can work, but even if you do so, lead deposits can form.

    We need to get the lead out of our fuel. I suspect a fair number of engine failures are indirectly related to lead issues. But since there was no option in many cases to go without lead, implicating the lead was not stressed in the tear down report.