Ethanol: A very real danger

Ben Visser is an aviation fuels and lubricants expert who spent 33 years with Shell Oil.

In a recent post I discussed the problems with ethanol and water in a plane’s fuel system. I received a large number of replies and most were very positive. However, I did get a number of negative notes. For example, one reader wrote: “Ben Visser, go argue with your wife to get your stupid little victory! I’ve been using ethanol mogas for over 20 years without a drop of water showing up…You’d make a great corrupt politician.”

Two problems here: First is that this guy is definitely not married, because if he were he would know that you never win an argument with your wife. You only think you are ahead sometimes, but you never truly win. The other problem is poor logic. When looking at a problem, some people just go out and try it to see if it works in one application and then claim it will work in all applications. They should also look at the science behind the problem.

When ethanol first came on the scene, we started to test it in the lab. The fuels with ethanol cleaned out our fuel systems and caused a number of leaks. Most people think that when a fuel line is made of neoprene or Buna-N rubber that the name completely defines what that rubber is. What they do not know is that there are a number of different compounds of each of these products. When we ran hardness and swell tests on a number of different compounds of the more common rubber types, we found that ethanol affected them differently. For example, we found that some neoprene rubber hoses worked well with ethanol-containing fuels, but others would harden or swell a great deal. This means if a person drove a car or flew a plane with ethanol-containing fuel and did not have any problems, it only means that the rubber components in that particular vehicle were OK. It does not in any way, shape, or form prove that ethanol will work on all rubber fuel components. Likewise, there are a lot of different aluminum alloys — many that work with ethanol, but there are some ethanol will corrode.

Peterson Aviation and the Experimental Aircraft Association (EAA), who would benefit economically if ethanol mogas could safely be used in aircraft, have done their homework and have looked at the large amount of data available and have concluded that ethanol, when used in aircraft, represents a very real danger.

What amazes me is that people will read this and then hear of a report from an ethanol salesman that claims that ethanol fuel can be used in any spark ignition engine and believe it. Or they will drive their car or even build a kit plane and fly it on ethanol-containing fuel and then tell everyone that that proves that ethanol is safe for every airplane ever built.

If these people really wanted to help aviation, they would accept the fact that ethanol and aviation do not mix. They could then start working to get Congress and the EPA to pass a regulation that requires that all oil companies offer at least one grade, premium, that is ethanol free. This would make it safe for aviation, old cars, boats, chainsaws, etc., to operate safely. They can then safely go crazy with the other grades.

Now I know that makes a lot of sense, but I am sure that there will be a few people who will be offended because their neighbor’s cousin’s boss’ brother-in-law heard a guy in a bar claim that ethanol is just alcohol and he has been drinking it all his life, so it must be safe. And this proves conclusively, beyond a shadow of a doubt, that that Visser fellow is full of you know what. Well, according to my wife, they may be right, so I will close now and go see if the fish are biting.

You can contact Ben Visser at


  1. says

    Mike Perkins –
    If you see “water” in a tank of E10, you are not seeing water. You are seeing all of the ethanol and all of the water it absorbed and you have phase separation, which is irreversible. You are left with a very corrosive compound of unknown properties and a fuel of unknown properties. It must all be drained out, treated as a hazardous material and the rest of the fuel system cleaned out and checked thoroughly. Just another of many reasons that ethanol blended gasoline is not appropriate for aircraft use, especially when you don’t have to use it, the gasoline producers can make ethanol free gasoline just fine, been doing it for decades.

  2. Mike Perkins says

    I believe that any water molecules wandering around in ethanol will attach to alcohol molecules and therefore remain in solution and be invisible. Is it not true that no one would ever see any water in a system containing ethanol except if there were so much water that no “free” alcohol remained?

  3. says

    Dennis Reiley – So what? The gasoline producers have been making ethanol free auto gasoline, a recognized legal aviation fuel, for many more years than they have been making E10. It is a universally available fuel today. Why would you want to fly with a fuel that provides less energy and presents a myriad of other problems when the fuel you need is readily available now.

    And you conveniently ignored the most important aspect of why “Today’s auto’s are fully capable of using ethanol fuels in all temperature ranges from the tropics to the Artic Circle.”, because modern car engines have computerized fuel injection systems that try to make adjustments for the changes presented by ethanol, if they have the proper fuel maps, which most of them don’t, yet. Probably why the mileage decreases we see in a lot of cars don’t match the physics, but then who really knows because nobody ever bothered to do statistically significant, large scale, independent studies to see if the promise of ethanol is really reducing our dependence on “foreign” oil.

    Besides, lets get to the real point of the Renewable Fuel standard in EISA 2007. It is to make E85. E10 or E15 is never mentioned in the act and it is NOT a mandatory E10 law. What we are seeing is an unintended consequence of a deeply flawed law that has serious economic implications that we are already seeing in the marine and aviation industry and will eventually result in a threat to public safety when the small engines used in portable tools don’t start or stop working in an emergency.

    Mr. Visser is spot on that the only sensible thing to do is prohibit the blending of ethanol in premium unleaded and let the ethanol industry and the politicians that brought us this foolishness “… go crazy with the other grades.” Ironic that there is this big push in the current political climate to get government out of our faces, but there must be no choice for those who need ethanol free fuel because the government knows what is best for us. That was pretty clear here in Oregon when the state legislature passed the first statewide mandatory E10 law in history with absolutely no exceptions.

  4. Jeffrey East says

    Thanks EAA and Ben Vissor for doing the research and keeping us educated and safe. The issues with Ethanol are very real and have and will effect every gasoline burning engine from airplanes to lawnmowers, from hoses to mixtures the problems are real!

  5. Dennis Reiley says

    Just because you accurately describe the problem with ethanol fuels does eliminate their use in aviation fuel. The auto industry discovered those problems “and” corrected them thirty years ago. Today’s auto’s are fully capable of using ethanol fuels in all temperature ranges from the tropics to the Artic Circle.

    The corrections include changing the materials in all seals that come in contact with ethanol and replacing all fuel system steel parts to one that is not conducive to rust.

    If the auto industry could do it thirty years ago the aircraft industry can do it now. For one thing the solution is well known and much easier to implement now.

    The aircraft industry needs to switch over its manufacturing to parts conducive to fuels containing ethanol, and they need to do it now. The aircraft parts industry also needs to switch over, ceasing to build any part that is not compatible with ethanol. This should include fuel tank replacements compatible with ethanol.

    I have never seen an industry so adamant (and so foolish) about not changing to accommodate necessary changes.

  6. Roger Reeve says

    I have used etanol in cars for several years. If you can buy it at
    .50 cents a gallon cheaper it pays off. I am not ready to put it in
    an aircraft engine at any cost.

  7. says

    I think this Visser guy is pretty good. But it really is time to get cracking on a suitable lead free avgas that won’t screw up our obscenely expensive engines. Or else pray that the diesel folks get their act together.

  8. says

    Ben Visser – always the refreshing voice of reason, and you are dead on with the comment about the futility of arguing with your wife. The EASA (European FAA) recently published findings on exhaustive testing of ethanol blends on engine components. It confirms what Ben and Cessna found. Swelling of rubber compounds was in many cases quite extreme. You’ll find the study here:

    Ben is right – we need an ethanol free fuel, and the onus is on the FAA and the EPA to preserve a supply of it since Mogas has been a legally approved fuel for 70%-80% of the piston engine fleet since the late 1980s. If you have not already, please sign the petition to the EPA asking for this:

    I received an email from an Argentine pilot who claimed ethanol blends worked fine in his Cub. His proof was that his engine has yet to fail in flight, and if it did, he has miles of flat ranchland in his area to use when his airplane becomes a glider. It’s these sort of rogue, irresponsible statements from pilots that get us all in trouble. If you are going to break the law and use an illegal fuel in your airplane, just make sure you don’t take any passengers along and you don’t tell the public what you are doing. When you do crash – and it will eventually happen – make sure you are far from people and property. Better yet, just fly responsibly and use the best of the approved fuels in your airplane.

  9. Nick says

    Unfortunatley, the guy that is using ethanol fuel in his aircraft is not only violating any STC that he may have, he is also one of those people that will eventually plow his aircraft into some unsuspecting innocent ground pounder and maybe take a passenger with him. He is the individual that will give USA Today fodder to bash all pilots and GA.

  10. says

    “Hi Test” Mogas without ethanol would work very well for aviation and the auto industry. Makes more sense than anything else I have read.

    One consideration/ Just how much lead pollution is admitted through 100LL as compared to all the pollutants just from the Trucking industry? No one is trying to come up with an alternate way to transport on the surface. Just the other day I heard on talk radio how much objection there is to modernizing and building a new Rail system in the US. Imagine the crude oil / pollution savings that would make. Oh BTW I bet the economy would sore for at least ten years while it was being built, especially in the private sector!
    Personally, I would make a large bet that the amount of lead pollution from 100LL world wide would be comparable to a small grasshopper fart in a Hurricane the size of Katrina.

Leave a Reply

Your email address will not be published. Required fields are marked *