Airworthy AutoGas prepares for takeoff

Mark Ellery doesn’t understand why aircraft owners “want to purchase fuel at a higher cost” than what he pays for the autogas that fuels his Citabria.

“What I don’t understand is, given the imminent demise of 100LL, and given that autogas is suitable for use, and has been approved for use for over 30 years now, why on earth is all of the focus on identifying and certifying one fuel, 100UL, which, at the end of the day, really only serves 20% of the GA fleet? That sounds like the tail wagging the dog to me.”

“I am a member of the 80% of the GA fleet that doesn’t want 100 octane, doesn’t need 100 octane, and doesn’t want to get stuck having to pay for 100 UL that, trust me, if and when one ever does get ‘certified,’ will end up costing more than today’s 100LL,” he continued. “The solution to the 100LL problem is complicated, and 100UL, in and of itself, is not the answer. Airworthy AutoGas will be an affordable alternative for 80% of the GA fleet, at less cost to the pilot. Airworthy AutoGas also is not the solution — it is part of the solution.”

A pilot and chemist who is the force behind Airworthy AutoGas, he admits he’s frustrated. He’s actually had FBO owners slam doors in his face.

And during a flight to this year’s AirVenture in a Piper Archer fueled by Airworthy AutoGas Premium 93 Unleaded, when faced with having to ship drums of the fuel to four airports, “not one FBO helped,” he said.

But that didn’t stop Ellery — at least not this time.

About six years ago, Ellery’s father-in-law, Roy McCaldin, a B-17 commander during World War II who regularly burned autogas in his personal aircraft, took him to Ryan Airfield in Tucson to meet with the airport manager, to discuss autogas.

“To make a long story short, he said that the airport manager wouldn’t allow it on the airport,” Ellery said. “That took the wind out of my sails, and I decided that if I was going to get that kind of response, then why bother?”

He shelved the idea for five years, then decided it was time to move forward with it. He began tinkering in the lab and came up with his patent pending formulation that meets the D4814 spec.

“In order to get approved in as many engines as possible, I decided that it not only needed to meet the D4814 spec, but it also had to meet Lycoming SI 1070,” he said.

Of course, it also had to make economic sense. He had to convince his employers, who also own a very large motor fuel terminaling facility in Phoenix that supplies a large portion of the fuel in the region — including 100LL — that it was worthwhile to go into this new business.

Airworthy AutoGas Facility“Aviation is such a tiny little segment of the market,” he said. “We had to downshift to get into this little — but important — business.”

He crunched the numbers and although it was a “tough sell,” was able to show “there is money to be made,” he said. “I demonstrated that we could make a living — not a killing — but the whole angle is to drive the cost of flying down.”

The company’s owners agreed and set up a separate company, Airworthy Autogas, LLC, which is set to begin production on Oct. 28, with a capacity to produce 500,000 gallons a month.

He said he’s talking with a lot of different entities, but can’t reveal, just yet, who.

Airworthy AutoGas Load RackHe does admit he hasn’t “sold a gallon,” but anticipates that his initial clients will be flight schools, and that they will get this business “off of the ground.”

He realizes that there is a lot of educating to be done to get Airworthy AutoGas into airports and flight schools, but he is willing to keep his nose to the grindstone until it catches on. As the producer and wholesaler, he can’t set the retail price, but does say that Airworthy AutoGas will be “substantially” cheaper than 100LL.

“I’m plugging away here with the idea of eventually serving North America with Airworthy AutoGas,” he said. “I’m in it for the long haul. I burn autogas in my own plane. It’s a better fuel for many aircraft than 100LL.”

What about your plane?

Experimental and homebuilt aircraft can use Airworthy AutoGas without an STC. Aircraft certified for any other avgas must get an STC for autogas.

Ellery reports that work is underway with manufacturers to TC airframes.

“Lycoming has pretty much approved 93 UL in most of their engines, so it really is up to the airframers to take it from here,” he concluded.

For more information:


  1. Vaughn S. Price says


  2. Jeff says

    I have a STC for mogas. But I don’t use it because of the hassle in testing the fuel, hauling it in, getting on a ladder to fill up with 5 gallon jugs etc. I would love mogas at my airport but 100LL is a secondary fuel here, Jet A is the big seller. Of the 100LL customers at least 50% can’t use mogas. They simply aren’t going to put in the equipment the time and expanse to offer what is a small part of their business.If they carried mogas it would only be maybe 5 to 10% of overall fuel sales. Got to love the fuel purchases by business jets!
    While understanding all that I am still pushing for mogas at my home airport, just not getting very far. It’s all economics. Why spend $50,000 to carry mogas when everyone can use 100LL?

  3. says

    It will be a very good thing to get rid of the lead as it really fouls up an engine. And it will be terrific if the price is something that GA can live with. But for me, if it has the same affect on me as does auto fuel, I can’t use it. To me the vapors of auto fuel are very toxic and if I get any of it on me, there is no way I could get in a small plane with those fumes. Apparently this bothers no one else as I never hear talk about it. Auto Fuel, just plane stinks.

  4. Sarah A says

    Back when I was learning to fly there were four different grades of aviation gasoline out there and I remember both 80 octane (red) and 100 octant (green) available everywhere. The for some reason somebody decided that we had to have a one-size-fits-all fuel and 100LL (blue) came on the scene and it has been nothing but trouble for the majority of the GA fleet ever since. We need this choice to be available again and if 100UL is really expensive, keep in mind it is only needed by a small fraction of aircraft. To force it on the rest of us to help keep cost down is outrageous. Lets go with a fuel that the majority can use and the rest will have to work it out for themselves. That may sound selfish but the tail should not be wagging the dog. Let the 20% adapt, not the 80%

  5. says


    Yes the Lycoming SB approves some automotive gasoline. Lycoming however does not approve the airframe. EASA’s airframe approval only relates to aviation gasolines. The reason your Comanche isn’t already approved for autogas is because it failed our flight testing, and not because there is a prohibition on fuels with an RVP higher than 9. That is a Lycoming requirement, not an FAA prohibition.

  6. says

    Todd Petersen;
    The latest copy of Lycoming SI 1070 S does list two unleaded auto fuels; one manufactured under ASTM D4814-09b in both 91 and 93 AKI, and the other manufactured under EN 228:2008(E) in 93 AKI. EN standards are European standards.
    Lycoming does permit the use of these two unleaded auto fuels in some of its engines.
    Both fuels must had a vapor pressure that falls under Class A requirements which are a maximum of 9 psi Reid Vapor Pressure. Auto gas from the local station does not have that requirement and that prohibits it from being approved under STC on certain tightly cowled airplanes–at least that’s what I concluded after reading the reason why my Comanche hasn’t been granted an autogas STC.
    No ethanol or methanol is permitted under either manufacturing specification.

    • says

      “Both fuels must had a vapor pressure that falls under Class A requirements which are a maximum of 9 psi Reid Vapor Pressure. Auto gas from the local station does not have that requirement …”

      While it is true that the “local station” does not have an RVP requirement, the EPA and states air quality departments do. If you’ve seen the OPIS terminal reports for all gasoline production across the U.S., gasoline universally available today is maximum 9 RVP throughout the year and 7.8 RVP in most urban areas during the summer. The reason that essentially all gasoline is max 9 RVP today is because that is the EPA limit for the entire continental U.S. during the summer.

  7. Mark Priglmeier says

    At less than 4 bucks a gallon, I have been using autogas for quite some time now here in MN. Right from the local gas station. Non-ox 91. It’s here. It’s now. It’s available (in MN anyhow).
    Don’t forget that option to get gas right from the local automotive fuel station pump TODAY! Good luck in your area with getting non-ox fuel. But if you can get it, test it and save some big bucks…right now!
    Don’t forget, per the FAA, you are allowed to self fuel.

    I am on mo way!

    Take care, save some dough and see you in the air!


  8. Kent Misegades says

    The myth of liability for mogas was explained in this GAN blog posting:

    Contracts with Avgas suppliers that forbid the sale of mogas would probably not stand up to any legal contest. It is clear however that an Avgas supplier will not extend insurance coverage to mogas provided by others, but the additional cost for it are quite modest and readily available from aviation insurers.

    • Dj Merrill says

      Kent, how do I get in touch with you? Local airport manager says if I can make a good business case for mogas he would consider putting it on the field.

  9. EdB says

    My gas facility sells 100LL ($4.60/gal) which is less than I’ve found AutoGas. I’ll stay with Av gas until it goes off the market for two reasons: It’s cheaper in my area and I understand that av gas has a longer “shelf-life” than autogas.

  10. Jeff Scott says

    And where are the alphabet soup guys on this? They are out there demanding a 100LL drop in replacement that will be so expensive it will drive many of us out of aviation. Sure glad I have them representing me. Way to go Mark!

    • Kent Misegades says

      Way to go also the 115+ airports across the country that have been selling mogas for decades, despite a concerted campaign from our so-called representatives to force a single fuel on all of us, whether we want/need it our not.

    • Kent Misegades says

      7B3, Hampton, NH airfield, 27 miles east of KMHT, sells mogas. Why not work with their mogas supplier until Mark can get his fuel distribution network setup?

  11. says

    Steve – EASA granted blanket approval in Europe for new “Aviation” fuels, UL91 and Hjelmberg’s Avgas. It had nothing to do with automotive gasoline. People are easily confused, looking just at the numbers – thinking 91 means it is autogas but it’s not. UL91 is an aviation gasoline with an aviation vapor pressure. EASA has not issued blanket approval for automotive gas.

  12. Len Assante says

    Great story. Part of the problem is the entrenched old guard of fuel distributors, FBO owners (some of them) and airport authorities (some of them). I’ve been told by more than one FBO owner that they’d love to offer mogas on their fields, but their contracts with their avgas distributors don’t allow it or their airport contracts won’t allow it or their insurance companies won’t allow it.
    The very industry people like Mark Ellery are trying to save is in many cases hindering progress towards that salvation. When GA dies out, and avgas suppliers are left holding a bunch of empty hoses, tanks, and trucks, they’ll have no one to blame but themselves. Lower the cost of flying (via cheaper fuel), and the number of hours flown will increase. That’s Economics 101 day 1. More hours, more pilots, more planes means more business for this industry.
    For once, let’s look big picture instead of today’s bottom line.

    • Kent Misegades says

      Well put Len. Ignorance among so-called aviation leaders regarding mogas is shocking. Even the head of aviation fuels for Phillips66 had no idea that mogas was approved by the FAA 30 years ago when I asked him why they would not offer it in a chance meeting in Oshkosh two years ago. With industry leaders like this, it is no wonder it has been an uphill battle for mogas. One of the biggest advocates for mogas, Paul Poberezny, was ignored by the same people who profit from AirVenture these days.

  13. says

    At AirVenture this year I learned (from Mike Kraft of Lycoming) that the European Aviation Safety Agency (EASA) had done an across the board approval of all airframes that have an engines listed in the latest Lycoming approved fuels Service Letter (SL 1070S).
    SL 1070S includes all the Lycoming engines that were approved for 80/87 and 91/96 octane av gas.
    I’d love to see the FAA do the same.

  14. Mark says

    Finally! Clear thinking, and a connection to a vendor. This could work!

    If you get as far as Texas, please let me know.

    Carry on!

  15. Tom says

    This IS what we have been waiting for – 93 with no lead and no ethanol. I will probably seriously consider getting the STC when this fuel becomes readily available. What is going to happen though when the public finds out that they might be able to get the stuff at the airport and use it in their autos in order to avoid the ethanol? When the ethanol folks find out that there is a way around buying their stuff, then they are going to be on the politician’s door step don’t you think? Also these auto driving folks would be paying the aviation fuel taxes but not the highway taxes when driving their autos? How does that work?

      • Kent Misegades says

        But some airports do any in most cases this is perfectly legal. Highway versus aviation fuel taxes make this a bit complicated, but not if the fuel is for off-highway use, eg boats, power tools, race cars, etc. Airport managers simply need to check on the rules and think a bit outside the box. The issue of liability is also a myth.

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