Lead pollution could be reduced by 176 tons/year through Mogas

The GAfuels Blog is written by two private pilots concerned about the future availability of fuels for piston-engine aircraft: Dean Billing, Sisters, Ore., an expert on autogas and ethanol, and Kent Misegades, Cary, N.C., an aerospace engineer and aviation journalist.

We have estimated that aviation would produce 176 fewer tons of lead annually if all the aircraft that could be using Mogas (91 octane ethanol-free gasoline) in the U.S. would stop using 100LL (Avgas) and switch to Mogas. Here is our reasoning:

If general aviation uses about 200 mgy of leaded avgas/yr. (according to EIA in 2009) and 80% of these aircraft (those that could be using Mogas instead of avgas) represent 40% of that avgas consumption, that is 80 mgy.  Since avgas contains around 2 grams of lead/gallon, that represents 160 million grams, or 357,750 lbs., or 176 tons of lead that wouldn’t spewed into the environment each year.

The best part of the Mogas solution is that it costs very little to achieve, is a drop-in replacement for avgas (and can be mixed with avgas), has a 20-year record of safety and affordability, and will save pilots 25%-100% annually on fuel costs, depending on where they now buy 100LL.

What would be required to get Mogas at our airports?

  1. The EPA prohibits the blending of ethanol in premium (91 or higher octane) gasoline, assuring a supply of the fuel. There are millions of other consumers who would welcome this since hundreds of millions of engines in vehicles/boats/ATVs/snowmobiles/classic cars/etc. and most vehicles built before 2001 should not be run on ethanol blends.
  2. Airports are supported — through various federal and state programs already in place for airport improvements — in their acquisition of an additional small self-service fuel station for Mogas. Between 4,000 to 10,000 gallon capacity would be quite adequate for most.

No modifications are required of these aircraft other than in some instances the purchase of a Supplemental Type Certificate (STC) allowing the use of Mogas.  These cost well under $1,000.  There are already some 60,000 aircraft in the U.S. now with these Mogas STCs.

We estimate that within two to three years these pumps could be in place and, with it, a near halving of the levels of lead pollution now created by aircraft in the U.S.  The positive impact on the affordability of flying would be very significant.


  1. says

    I don’t like leaded gasoline because it has bad affect on my engine and will use an unleaded fuel when it is available at airports. There is no point in trying to get people to switch to “MOGAS”, when it is not available at airports. Big oil will fight to the death to keep a substitute from ever reaching the market.

  2. says

    Al –

    “Studies have shown (and you have quoted in the past) that about 20% of the GA fleet uses about 80% of the leaded avgas. A simple switch to currently available mogas would decrease aviation fuel consumption by 80%, …”

    Your numbers are not logical and your second sentence makes no sense and we have never quoted that in the past.

    Please supply documentation for your claim 20% of the GA fleet uses 80% of the 100LL. We have consistently claimed that 20% of the GA fleet might use 50-60% of the 100LL not the 30% uses 70% that is claimed by the alphabets and media, except GAMA.

    So if the 80% of the fleet that needs neither 100 octane gas or leaded gas switched to mogas then 100LL demand would drop 40 to 50%, not 80%. And producers are already making the economic decision to stop making 100LL because demand declines steadily each year, especially now that GA is tanking.

    Your conclusion is specious. The 80% of GA that doesn’t need 100 octane gasoline should use it to keep demand up and incur the additional costs for fuel and maintenance so that the 20% of aircraft that need it will have a continuing supply … maybe.

    A 100 octane replacement will be found. If TEL goes away, highly likely within a few years, or the refineries stop making 100LL, a possibility as demand decreases anyway, then there will be a crash program to find the replacement. But that is no reason to burden the majority of fliers with an economic penalty, thus driving more of them out of aviation and further shrinking GA.

    Our proposal has always been, there should be 100 octane gasoline on our airports for those who need it, and there should be ethanol free mogas on our airports for those who can use it, they are both approved aviation fuels. That’s all we have said. We have never said it should be one fuel.

  3. says

    More comments:

    Mark C – one needs to convince the EPA, FOE and our alphabet groups that they are saving the planet by supporting Mogas. In our recent contacts with the EPA and FOE, it appears that their thinking is moving in our direction. Aviation alphabet groups remain sadly nearly 100% focused on the 100LL situation, although it affects only 20%-30% of all airplanes.

    J Bouisseau – In your shoes I would have contacted the issuer of the MOGAS STC and sought a solution. Did you ? What did they say? Reports such as your have been very rare; Mogas has enjoyed a long history of safe operation, lower fuel and maintenance costs when used according to the engine/airframe combination permitted by the STC.

    Bruce – what engine powers your Cessna? I am not aware of any common engine with a Mogas STC that permits even one percent ethanol. It makes no sense to support ethanol blends in aircraft engines since the ultimate goal of the federal EISA 2007/RFS mandates is to take all fuel up to E85, i.e. 85% ethanol. E10, or the newly approved E15, is just an early phase on the efforts of the ethanol industry to use much higher levels. The lower energy and resulting loss of power and range in aircraft will make these intolerable. Where are you finding ethanol blends cheaper than ethanol-free Mogas? Ethanol is now more expensive per gallon than gas, making its use more expensive.
    Are you in Brazil by chance?

    Ray E – The EPA is aware and starting to pay attention. The FOE is perhaps the most responsive. The FAA and aviation alphabet groups remain nearly 100% focused on aircraft that need 100 octane fuels. Go figure.

    Cal – There is no prohibition today. We urge the EPA to do this, which would result in ethanol-free Premium. Since no state however checks on the levels of ethanol in fuels today, we’ll still need to check for ethanol as there will be cheaters, assuming ethanol is cheaper than gasoline, which at the moment it is not due to skyrocketing corn costs.

    Al – We are not suggesting that aircraft needed a 100 octane fuel use Mogas. We are focused on the needs of the 70%-80% of all piston-engine airplanes that could now run legally, safely and for less money on 91 octane ethanol-free Mogas. Clearly the smaller camp, those needing a 100 octane fuel, have plenty off people looking for solutions. But who is concerned about the needs for the majority of airplane owners, the entire LSA industry, Sport Pilots, flight schools and all others who struggle just to stay in the air in this economy? We have not repeated the 20/80 or 30/70 myth, and we believe that this is a myth. Based on our estimates the 80% who could run on Mogas burn around 40% of the 100LL used today. In Europe it is closer to 50% from a recent report there. With many heavy piston owners upgrading to turbines and light jets, and with the rapid growth in Mogas-powered LSAs, the percentage of airplane owners who need a 100 octane fuel will continue to decline. Most airports now just break-even on 100LL sale, making most of their money on Jet-A fuels. Supplying pilots with 100 octane and Mogas should be seen as services, not profit centers, just as airports install expensive AWOS systems, parallel taxiways, new FBO buildings, etc. Non make money and are not really necessary, but airports want to make their airports as attractive as possible to pilots.

  4. says

    Brad – this may be true but the EPA is solely focused on lead emissions from fuels. 100LL has lead in it. Mogas does not. That’s all that matters to them and the Friends of the Earth, the group that is putting pressure on the EPA to ban 100LL.

    Bill – there are plenty of refiners making and selling ethanol-free gasoline. See http://www.PURE-GAS.org for a listing of stations logged in the past year. There are some 16 million boaters in the U.S. who buy their fuel at these stations, and who knows how many owners of snowmobiles, ATVs, etc. Your analogy regarding the mass of the earth is irrelevant to the EPA and FOE – we have already lost that battle.

    Harry – we are not suggesting the aircraft needing a 100 octane fuel use Mogas. We are focused on providing the right fuel for the 70%-80% of all piston-engine aircraft that today could operate today safely, legally and for lower cost using ethanol-free premium gas, aka Mogas.

  5. Doug Rodrigues says

    Vapor lock is to be considered. I tried it in my Lyc O-360A1D. Seemed to run fine, but I notice that the mixture control had to be set to a slightly richer position for the same power output at high elevation. Anyway, on a summer day, my wife an I landed at a near sea level airport with a restaurant to have lunch. We found the restaurant closed and out of business. Without allowing for a cool off period, we got back into the plane and took off. Upon takeoff, the engine began runing as though it was starving for fuel. Within about 10 seconds, the engine smoothed out and ran fine. That never happened with AvGas. I continued using auto fuel often, where it could be purchased at small airports, but was always aware of the conditions which caused the vapor lock to occur.

  6. Andy B says

    Is it possible for someone to come up with a model for carbon offsets for GA? It’s easy for someone to do for an airline trip or a car so why not GA? If the engine manufacturers (say Lyc/Cont and Rotax) could provide the data, perhaps someone could put a system together allowing for offset purchasing by owners.

    I would spend a bit on offsetting my footprint if I knew the data was right and had a respectable source to do so (there are several). I also have Mogas STC on my PA22 but who can find it?

  7. Al Uhalt says

    You are pushing the wrong grape up the hill! You should be pushing for a suitable substitute for leaded avgas (which may very well be beneficial to automobiles and other conventional engines as is lead) rather than eliminating it which would ground virtually all of the conventially-powered, high-performance, supercharged commercial and private aviation fleet! FOR SEVERAL REASONS, mogas is NOT “a drop-in replacement for avgas” or we would have done that years ago for economic reasons alone — both from the consumer and the refiner/distributor standpoints.

    The the numbers you now quote have changed. Studies have shown (and you have quoted in the past) that about 20% of the GA fleet uses about 80% of the leaded avgas. A simple switch to currently available mogas would decrease aviation fuel consumption by 80%, making it hardly worthwhile for fuel suppliers to even service most airports — and doing so would decimate a national industry with consequential “domino effects” into other sectors of the national economy.

    Let’s all get behind the effort to develop a suitable substitute for leaded avgas which may well enhance national land world commerce rather than simply eliminate it with the resulting disastrous effects to our industry and beyond.

    Al Uhalt

  8. says

    If the EPA prohibits the blending of ethanol in 91 or higher octane fuels, then 5 of the 6 local gas stations are violating the prohibition. Except for one station currently selling ethanol free on all grades, the others have 93 octane mixed with ethanol to make E10.

    Just an observation.

    Cal Hoffman

  9. Ray E says

    Are the proper authorities getting this word? Is the EPA and the FAA aware of this immediate solution? Hey EPA, you can reduce the lead substantially if you would wake up and use some common sense. Get premium mogas to our airports without ethanol. This is not rocket science.

  10. Bruce Gustafson says

    I use multi-fuel aircraft in my aerial survey business. The aircraft are rated to burn LL/Mogas/Ethanol – all STC approved. Using Ethanol at $2 less a gallon than AV Gas and $1 a gallon less than Mogas is saving me about $800 a week in my fuel costs per plane and doubles my TBO to almost 4000 hours for a Cessna. Somthing else to look into – we really need all three options.

  11. J Boisseau says

    I tried using latest ethonol free 91 octane fuel in my stc’d Bonanaza 225 eng and had serious vapor lock. had to go back to 100LL

  12. Mark C says

    But how does anyone make millions off this solution? How can politicians leverage it to make it look like they’re doing something useful? And would the whiners and fun-haters accept it as a solution, or would they continue to wage a class war against all those rich, spoiled pilots who would rather poison children than give up their toys, while soliciting donations from frightened soccer moms?

  13. Harry Carter says

    Let them be the first to fly with this blend and see what happens. Its easy to say that mogas will work, but reality is it may work in low performance aircraft only. Remember the Mobil one oil problem, in theory the oil would have worked great, but ended in disaster. Remember when low-lead and no-lead gas first came out in the 70s and auto manufacture companies had not improved the valves. Again, the biggest problem is aircraft engine manufactures, government, and suppliers have all sat on their thumbs and now there is a big push. Many will suffer due to a few who think they know what to do.

  14. Bill Campbell says

    Though long in tradition and regulation, the idea of purchasing an STC for Mogas, when there is no physical alteration to an aircraft, is ludicrous. The FAA and EPA, as usual, are getting in the way of exactly what they want to accomplish. Pilots should not experiment with engines to see if they will fly on Mogas but the FAA should promote the publication of a list of approved airframes and engine types that are known to be safe on avgas.

    The real problem with Mogas is that we don’t have any refinery making alcohol free Mogas. The tree huggers created this law of unintended consequences.

    A solution with a useful STC would be a header tank, containing 100LL to be used only at takeoff and climb power. Almost all engines can operate at 65% power on high octane, alcohol free Mogas without detonation at cruise power settings. The throttle position could easily determine which tank should provide the appropriate fuel mixture. Between that and LOP operation fuel cost could be cut in half and emissions reduced 30%.

    BTW the earth weighs (has a mass of) 6,000,000,000,000,000,000,000 tons. Divide that by 176 tons and see if that number could possibly make any difference. Even the smallest volcanoes put tens of thousands of times more lead in the atmosphere than all of the avgas burners in the world combined. If we eliminated all 100LL the effect would be so negligible that it would be impossible to measure in the atmosphere.

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