Going Direct: Ready for Rehab? GA’s Unseemly Addiction to Low-Lead Avgas

There are things to love about flying and there are things to hate about it. Turbulence, ramp fees and mid-TBO overhauls make the not-so-nice list. As do fuel prices.

One thing that doesn’t make the list of things most pilots hate about GA is our contribution of lead to the environment. The use of just a tad of lead in our avgas is the leading contributor of lead to the environment, but given the relatively small size of the GA fleet, we don’t take much heat for it.

Which is a good thing, because there aren’t any good options available just yet. In a very real way, we are addicted to 100LL.

I’m halfway joking, of course, because none of us want to use the stuff. It’s expensive, it costs a lot and then there’s the price of it. If it cost a buck a gallon, we’d all want to wrap our arms around it and give it a big hug, but for now, it’s the thing standing between us and really affordable flying. I know, I know. If you can’t stand the heat, stay out of the engine block, but as much as many of us are ready and willing to pony up the dough for 60 gallons of $5 or $6 fuel for a one-way leg in a Skylane to somewhere cool, the “able” part of the equation is missing. For a lot of pilots, spending four hundred bucks for a trip that’s 300 miles out and 300 miles back seems like a lot. And if it seems like a lot to an airplane owner, then by definition it is a lot.

The problem is that there are few options.

Electric power is the Holy Grail. If it were here today as a viable replacement for avgas or Jet-A burning engines, those electric motors would be flying off the shelves. But they’re not here and they’re not really even close.

The other savior technology is diesel, and I’m a fan of diesel. Diesel aero engines are fuel efficient, quiet and cheaper to put fuel into because they use less of it and because you can put cheaper fuel into most of them. That 600-mile round trip referenced before in a diesel-powered Skylane would be about half the price for fuel, again, because it’ll burn a lot less fuel along the way and because they fuel could be cheaper, especially if the engines were approved to use diesel and not Jet-A only.

But diesels haven’t caught on because the engines themselves are expensive, a lot more expensive than the gas piston engines they replace, and when you work in the cost of the retrofitting, they’re hard to justify. This fact is being blamed for the slow sales that some assay is the reason Textron Aviation’s decision to discontinue its Skyhawk 172 JT-A program. (You can still get the same basic plane with the Continental diesel engine installed by STC after the fact, an option few are likely to ask for, though.

The conclusion is that we’ll be sticking with our conventional aero engines for a while but putting unleaded fuel in them, if there winds up being a commercially viable and affordable 100UL out there.

That is a far bigger “if” than it was just a few months ago. In June the FAA announced that it was pushing back the date for its approval of a 100 LL replacement after it found there were too many differences between the two candidate fuels, from Shell and Swift, and 100LL. What this means is anybody’s guess because the FAA has offered no details. But it presumably means that coming up with a plug and play fuel won’t be as easy as we’d all hoped, though none of this almost decade long program has been easy.

What remains to be seen is how available those 100LL replacement fuels will be and how much they’ll cost. Will they be cheaper than 100LL? With all the investment that will need to be put into development and production and delivery, it’s hard to see how they could be anything but substantially more expensive at the pump than 100LL. Though I hope I’m wrong about that. Because 100LL is going away soon, and we’re definitely going to need a new fuel to do our avgas thing.



17 thoughts on “Going Direct: Ready for Rehab? GA’s Unseemly Addiction to Low-Lead Avgas

  1. Christ, there’s been more talk than action on this subject more than ADS-B even! Let’s get with a replacement NOW as well as STC’s for auto -gas. These both exist just too much ass-dragging waiting for teh 100LL to go dry and maybe that’s what it takes vs. writing about it, again.

  2. What about Swift Fuels’ 94UL? What typical GA planes is it usable in? Why aren’t ordinary pilots flocking to it?

    I suspect the real reason that GA is holding on to 100UL and not beating a path to Swift Fuels’ door, is that old bugaboo “market resistance”. Put into human terms, that means that a large share of pilots have no interest in whatever innovation is being “market resisted” and want to stick with the tried – true or not.

    As for spewing lead into the atmosphere, I don’t get a sense that most pilots care that they’re doing it.

  3. Most of the price I pay for 100LL Avgas goes to pay for special handling (verified quality, no water!) and for the excellent network of controllers, navaids, airports, and services that make flying in America so great. I guess I’m in the minority, but I am delighted to pay for such freedom and capabilities through the fuel tax. Even if my Bonanza with IO-550 is certified to fly with unleaded fuel and it is available, I expect to pay close to the current price for special handling and aviation taxes.

  4. Great article. Leaves me curious though – what about a mogas option? Infrastructure is there. Price is definitely right.

  5. I have always liked reading your writings Mr. Goyer, but I have to say, “that the price of avgas 100LL will and never go down in price. As far as the industry making a replacement for 100LL, its not the difficulty of making a new fuel that can take the place of 100LL, their main concern is,” how can we change 100LL to a different fuel and still continue to charge the incredible high price we do today”. It’s all about ripping off as much money from you and me, it’s been going on for so long no one want’s to sell it for less money!!! That’s all it is, fuel is easy to manufacture, the big problem is how can we go about it and still charge 400% more than it cost. I remember in the mid 1960’s when Standard gas stations had the red, white and blue gas pumps, blue was regular, red was ethyl, and white pump was called custom supreme, it was 100 octane leaded gas, same as 100LL. The cost was 0.33 cents for reg. 0.35 cents for ethyl, and 100 octane was 0.39 cents per gallon, we used to fill up our race cars with custom supreme and go to the drag strip and race all day long. Having said that I must say, “fuel is like anything else” that is in demand. The good old american way to continue ripping people off as long as the demand is there, meds for people with diabetes, meds for people with cancer, and the list goes on and on. I suppose if we dare boycott these products we would only hurt ourselves. Sorry don’t mean any harm, just my unbiased opinion. thanks

  6. We should consider high-ethanol avfuels, ie 30-50% ethanol (perhaps higher) and the rest, gasoline hydrocarbons.

  7. Great article. Made me curious about mogas though. Seems like the price is right, and the infrastructure is there. Is there a reason that isn’t pursued?

  8. …to preserve general aviation in this country, there needs to be congressional and presidential action taken to convert all currently registered aircraft to diesel power funded by emergency money derived from the accumulated fuel tax, often mis-spent since July 1970…otherwise, we all say goodbye to general aviation…captain mike McKenna, 1668380 ATP, CFI

  9. How about non-ethanol mogas?? Duh!!
    My Skylane likes it better than 100LL. Not really a problem getting it and fueling my airplane. I use metal NATO jerry cans and standard fueling safety procedures.
    No Lead! Most GA airplanes can burn it with STC (something like 75% of small aircraft).
    How about making the fuel readily available at GA airports. Duh!!!

  10. A couple of years ago in an article in Flying (I think) about diesel aircraft engines they said the same thing this article said about diesel in small aircraft. One thing they pointed out was that GA in Europe would like diesel engines much better then GA stateside because diesel in Europe was less in price then regular gas, which it use to be here in the U.S. until they ( the oil companies) found out we not only want it, but were putting diesel engines in everything from pickups, to farm tractors and some cars. My question is why is diesel more expensive in the U.S. then Europe, not to mention our cetane rating here is only 40-45 and in Europe it’s 60 a higher grade diesel. Diesel here is usually the price of high test or higher.

  11. The alternative is engines that are fuel efficient, modern and run on mogas………..see the ADEPT range that is now moving into production. lighter, more economical (fuel cost per hour half the cost of current engines running on Avgas. Diesel weight and vibration an issue. Visit the ADEPT stand 659 at Oshkosh to see real technology.

  12. The low cost solution for most GA aircraft today is ethanol free Mo-Gas sometimes referred to as “Rec Fuel”. Getting more of this into the fuel distribution system at FBO’s.

  13. There is an alternative to 100LL that will benefit the vast majority of the GA fleet. It is called UL94 Unleaded Avgas. I have been using it for years, and found it superior to 100LL and mogas. It is approved for over 70% of the GA fleet, costs slightly less than 100LL, does not produce the spark plug fouling, oil fouling, or sticking valves that we have all learned to live with. Also, no worries about mogas vapor lock, or fuel spoiling. If your aircraft is approved for 80/87, or mogas you should consider UL94. It is available at airports around the US, more are being added. Many of these airports have a chart next to the pump to confirm if your engine is approved for UL94 (most are).

  14. Most GA aircraft can burn non-ethanol Mogas. Most people don’t want to go to the trouble of figuring out how to get it to their airplanes. It’s worth it. 2.26-2.40 a gallon. Engines runs cleaner. I’m running an O-470 R and it runs great. Check your TCDS and you’ll see 80 octane was what the engine was designed to burn. I have 140 gallon tank in my pickup. Even if you just use 5 gallon cans and mix the fuel you’re saving a fortune. Just sharing what I do.

  15. The only thing you omitted from the article is the addictive smell of 100LL. This unique, memory inducing, odor has been part of my life off and on for 50+ years. Please tell me it will at least be around long enough for me to share with my future grandkids….no pressure to my sons of course.

  16. Capitalistic economies deplore vacuum’s, there will be a replacement. Necessity is still the mother of invention.

Leave a Reply

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