The fuel of the future: Is it already here?

Ben Visser is an aviation fuels and lubricants expert who spent 33 years with Shell Oil. He has been a private pilot since 1985.

I recently received a note from reader Scott Shroyer, who is looking to buy a used Cessna 182 with an auto gas STC. He wants to know if it is worth his time to buy the 182 “in hopes of finding auto gas at an airport to fill it up?”

A lot depends on which state Scott lives in as to the availability of auto gas without ethanol. I then forwarded his question to Todd Petersen of Petersen Aviation, who has sold more than 34,000 mogas STCs worldwide since 1983.

Scott’s question raised several questions in my mind. First, is it worth considering the fuel requirement of an engine in the purchase of an aircraft? I would say that it does at this time.

There are two advantages to an auto STC’d aircraft. One is that you can be sure that whatever happens with avgas in the future, your plane will operate on the new fuel with no modification. And two, you will be able to have some control over your fuel costs because you can always buy auto gas.

Another question concerns the future fuels debate. Why is everyone betting the entire future of general aviation on the development of an unleaded 100 octane fuel? The chance of someone developing an unleaded 100 octane fuel, and being able to market it at a price that anyone but an Arab prince can afford, is about the same as finding an 80°F day in North Dakota in January.

And why does everyone seem to think that 100 Motor octane is a magic number and that any unleaded fuel that meets this number will satisfy any aircraft engine ever built? And finally, there is this thing called liability that some people think will disappear for the common good of all mankind, if we only had an unleaded avgas. I am a realist, and I do not like the odds of this bet.

A better bet is if the GA community really got behind the use of auto fuel in LSA and STC’d aircraft and tried to increase the availability of this fuel on airports, plus work with fuel manufacturers to lower the lead level in 100LL. This would demonstrate to the EPA, et. al., that we are working at reducing the amount of lead emitted. For this to work it will require cooperation in the aviation community and some common sense by the government, but, hey, at least it has some chance of working.

I have always looked at the use of auto gas in aircraft with some caution. For it to work, it requires caution and common sense by the user. It is critical that an STC is purchased for every specific aircraft. Some people think that if one Cessna 172 can be run on auto gas, then all models of the 172 can use auto gas. Not true. If you plan on using auto gas, make sure you get the STC for your specific aircraft/engine combination, and then follow all of the limitations outlined in the STC. For example if you are doing your own refueling, you need to check for ethanol on every batch and follow the proper fuel handling procedure like your life depends on it, because it does.

Todd Petersen passed on that if you are looking for ethanol-free fuel, go to And if you go to, you can sign a petition urging the EPA to eliminate ethanol from premium fuel.

You can contact Ben at


  1. Ray E says

    If ethanol is such a great addition to fuel, then it should be able to sustain itself as such a fuel. I don’t thing us tax payers should be subsidizing this industry. Let the free capital system work its course. If ethanol is so great, then let it survive in the free enterprise system. If it is not, it will not succeed.

    In the meantime, let’s keep it out of premium auto fuel in order for the 70% of GA aircraft capable of using this fuel be able to do so. This will actually help with the EPA concerns by eliminating unneccesary burning of lead.

  2. Dennis Reiley says

    Well it’s about time more emphasis was placed on MoGas or auto gas or whatever you want to call it. People tend to keep older aircraft flyable and many of those need a high octane fuel. But that does not mean new aircraft power plants should use high octane fuel. The technology is there to upgrade the amount of power produced while lowering the octane requirements. All new aicraft should be built to handle ethanol fuels including the problems associated with storage of fuels with ethanol.

    Right now ethanol production is subsidized and has been for some time. That means it may or may not be used in gasoline in the future. But building new aircraft, or even replacement parts for current aircraft, that are not compatible with the possible fuels of the future is just plain foolish.

  3. says

    Here at Barnwell, we stock 93 Octane Mogas, ethanol free. The key is ethanol free. Without state level legislation to protect Mogas from ethanol, this will also go away. Few aircraft are certified to run on ethanol adulterated fuel and some that were are having that rescinded by the manufacturers.

    Cal Hoffman

  4. says

    Thank you for explaining the different reactions of ethanol with fuel tubing. That is particularly important for aviation. The company that built our ethanol plant also flys aerobatic airplanes fueled with ethanol. What have they done to make this a successful fuel?

    Nearly all of the problems with ethanol production have been addressed. Anti-ethanol efforts generally are using data that is years old. The following are examples.

    1. Corn now produces approximately 2.8 gal/bushel rather than the 2.3 of a few years ago.
    2. My corn yields are approximately 40 bu/acre more now than just a few years ago.
    3. Fuel use per acre has been reduced by 50%, using new farming methods.
    4. Our new irrigation methods usually use less than half the water of previous years.

    Using ethanol is one way of putting solar energy to work for us.

  5. Phil D. says

    … and what about the big-bore engines? Are we concluding that anything faster than 125 knots and climbs higher than that loitering buzzard “dead” technology?

    Are we really supposed to feel comfortable (heck—even safe) schlepping 87 octane from that Sav-a-Lot gas station into aircraft that have been designed “out-of-the-box” as finely tuned, high-strung, and tempermental?

    Listen: there’s more to this than meets the eye. This has all the tell-tale signs and fingerprints of those “gun control” advocacy groups … if the gun can’t be controlled, make the bullets prohibitively expensive or unavailable. Likewise the personal aircraft: our government’s strategy is to ground or severely restricting the range and utility of personal aircraft by eliminating the fuel. I don’t know about you, but now’s not the time to sink your money into a Cirrus, Bonanza, or Malibu.

    The same folk that are “threatened” by gun ownership … and are trying to limit internet access … are the same folk who are trying to eliminate “those little planes”.

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