Our expert’s take on the future of fuel

Every fall I help local farmers haul grain to the elevator. This year we had a very good harvest and the lines at the elevator were long. To pass the time, I brought along magazines from this summer to read and reread. I noted that every magazine had at least one article about the future of aviation gasoline. Since my byline in General Aviation News says I am an aviation fuels expert, I thought maybe I should address the subject and shed some light on it.

Now that harvest is over, I have also cruised the Internet and found a lot more “information” about the subject. So what has changed since my last column on this subject over a year ago? In reality, nothing.

The question then arises as to the meaning of all of these articles if nothing has changed. Do the writers not understand the “show?” That may be part of it.

For example, the head of Lycoming’s effort stated, “If you throw us a fuel, we can tell you within two weeks if it will work.” This indicates to me that they are testing a fuel only as to whether it will run knock free in their test stand engine.

What about all of the other engines in all types of conditions? What about fuel handling and compatibility with all rubber and plastic components? What will it do to a rag-covered aircraft when spilled on it? The questions go on and on. I think that most of the authors are writing from the viewpoint of what do we want and not from the viewpoint of what we can really expect.

Now I hope you do not think that I know all the answers, because I don’t. Just ask my wife. She could talk for several hours about what I do not know and never repeat herself. But I have worked for an oil company for more than 30 years and I understand a little about how they work.

The biggest problem with these articles is that they do not address the liability issue. Writing about future fuels and not discussing liability is like talking about childhood obesity and not mentioning poor diet or lack of exercise. You can put a lot of information forward, but you may not understand the whole problem.

I hate to sound like a broken record, but liability in the GA world is the most important controlling factor in what a company will or will not do. In this column, I would like to rate the future fuel options from a refiner’s point of view.

A little drum roll please: The number one choice by refiners is 100LL. Now I know that 100LL has received some “bad press” but it is the only fuel that meets the needs of all of the GA community and it has experience. I know about spark plug fouling in LSA and old 80/87 engines, but that is a problem that people are aware of. And it works with the fuel distribution system. Let us say we have learned how to live with it. In general aviation it is always the fear of the unknown that concerns everyone the most.

The second choice is a 94 unleaded fuel. This is basically 100LL without the lead. The beauty of this fuel is it is a proven commodity. It works in all of the distribution systems, it does not cause any aircraft fuel system problems and the refiners are all familiar with how to produce it — and the octane rating is well below that of 100LL. This means that every aircraft will need to be more or less re-certified on the fuel. This removes the liability of knock-related problems from the refiner and places it on the engine manufacturer or modifier. This is a huge difference.

The third choice is to get out of the business. Shell and Exxon-Mobil have partially removed themselves from the business, and others may follow. If you do not believe this, remember that Shell scraped a complete refinery in the middle of the world’s largest gasoline market (LA) just because the liability risk was too great.

Finally the fourth choice is one of the new 100 Motor Octane unleaded fuels. For this discussion I have lumped Swift Fuels, GAMI and all other candidates into one choice. There are several problems with this choice. The biggest is that these fuels are being sold as a direct replacement for 100LL and that they will meet ALL of the performance perimeters of 100LL. Not some, or maybe similar, but that they meet all of them. This puts refiners into the world of “the fear of the unknown.”

Until you put these fuels out into the market, no one knows how they will work in all of the fuel systems and aircraft that are out there under all types of conditions. When the industry went from 100/130 high lead to 100/130 low lead, the average lean rating went up several numbers and the average rich rating went down several numbers. The result was that we received a lot of knock complaints on the new fuel from end users.

Now, if one changes from 100LL to an unleaded 100 lean rating fuel on which you really cannot accurately measure the rich rating, we are expecting it to run knock free in every application and under all types of conditions. In addition, we lose the “lead bonus,” which has shown that leaded fuels have less knocking tendencies in the field than unleaded fuels of the same octane rating. And we are expecting the new fuel to perform as well as 100LL in all fuel systems and aircraft with no problems or issues.

If it does cause a problem, there is an army of lawyers just waiting to sue the refiners and get into their deep pockets to share the wealth. Maybe, just maybe, this may explain why none of the oil companies are waiting in line to jump into this business.

You may have noted that I did not include auto gas in the choices. That is a subject for another column.


  1. says

    Absolutely right. What you said about the “liability” issue. I appreciate if you extend your discussion and comments about the “potential Ethanol” to replace the LL100.
    How do you see the future regarding the “rare” and “expensive” LL100.

  2. Chris Hodges says

    What about butanol? Butanol is an alcohol that is equivalent in energy to 100LL, has a higher octane rating, can be produced from most sugar feed stocks (such as sorghum, beets, sugar cane, etc..) and does not cause the corrosion issues like ethanol. No engine modifications are required to run on butanol. The best part is that ethanol plants currently operating at 20+ billion gallons/year can be converted over to butanol operation and many companies such as GEVO are already working on producing iso-butanol from biomass. Considering that GA only uses 200 million gallons/year annually of 100LL, shouldn’t we consider testing butanol as an alternative fuel??

  3. PB says

    The thrust of the article is liability – so tort reform, long overdue, can address that. That’s if the lawyers who make up the majority in Congress and the Senate can have the guts to legislate to limit liability.

  4. Jeff says

    Like it or not TEL is going away. And if the wrong court get hold of the issue it will be much sooner. So lets just keep that in the back of our minds.
    Two things are driving the fuel issue, TEL and high prices. TEl is going away so we need an alternative and sooner than later. High prices are because we are a very small fish in the pond. As long as we use a boutique fuel the prices will be high. So what is the solution there?
    We can’t just throw out the 20% of planes that need the higher octane fuel, I would be willing to bet they may be only 20% of the number but buy a far greater percentage of fuel than 20%!
    We need to be very, very careful of EPA mandates. They are out of control. Just look at the permeation standards and venting on fuel lines and portable fuel tanks in the outdoor equipment and marine industries. They ended up with hoses that disintegrated from today’s fuels, clogged fuel systems and cause catastrophic failures to engines, yet the EPA didn’t back down.
    The new non vented fuel tanks similarly cause carburetor overflows, and flooded engines, costing the boating public millions in repairs. Bought a 5 gallon jerry can at Walmart recently? 3X the cost and being non vented the fuel pours at 1/3 the rate and causes spills! These are just examples of what has happened in the boating arena, and the EPA did not back down. Even though I suspect the new mandate causes more spillage and air pollution!
    So what do you think will happen if they get their teeth into aviation?
    The sooner we can get TEL out of the fuel the better. Head the EPA off at the path.
    I for one would rather see the 94 no lead alternative out there right now. 80% of the aircraft can use it with no modifications. Then lets look at engine modifications, engine timing and the development of additives that can be used for the other 20% to keep them in the air as well.
    (A company Valvtec makes an additive for the old marine inboard engines that seems to work well)
    94 no lead will also have the price advantage, get more GA small planes flying and should be available anywhere. What’s not to like?

  5. Kent Misegades says

    I look forward to the comments on Mogas. The suggestions above are for the small percentage of aircraft, under 20%, that currently need a higher octane fuel. That group will continue to decline as new mogas-burning aircraft replace older planes, and high-performance aircraft continue to move up to turbines.

    • Bill says

      The mogas solution is always pulled up as so simple. Yet it is not. The companie making migas do not want it used in aircraft.

      The 20% of planes that need something more are not going away overnight.

      • says

        Bill –

        “The 20% of planes that need something more are not going away overnight”

        They will if Innospec stops making TEL.

        Unless they are willing to support ADI STCs like those being developed by Air Plains.

  6. Rich says

    Of course the simple solution is to disband the EPA.

    We have been able to remove ALL the lead from trillions of gallons of auto gas but this just isn’t good enough for the fanatical “conservationists”.
    So we burn corn, which of course takes the corn out of the food chain and drives up the price of food while lowering the miles per gallon garnered from the gallon of fuel burned while not doing anything to lower the price of fuel. In fact increasing the price per mile traveled by lowering the amount of energy in each gallon you buy.

    The only people screaming about this are the few insane.
    Mr. and Mrs. America don’t give a wit about this because in reality it doesn’t affect them.
    And never will.

    I suspect there is plenty of stuff in the air that will harm you worse than the infinitesimally small, microscopic amount of lead coming from airplanes that is dispersed into the air thousands of feet above us up in the atmosphere.

    This is a solution in search of a problem,

    • says

      Rich –

      “This is a solution in search of a problem,”

      Actually it is more complicated than that. It was the removal of TEL from those trillions of gallons of auto gas that make TEL commercially untenable. The single company that makes it will probably stop making it long before the 100 octane replacement camel is in production because the miniscule amount that is necessary for the approximately 200 million gallons of avgas needed per year, and declining, will force the obvious business decision.

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