Avgas in 2011 — Logic will prevail

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.

As an engineer and a pilot, I believe that logic, combined with the amazing ability of free markets to decide between winners and loser, generally prevails, and even when do-gooders, politicians and bureaucrats do their best to throw a wrench into the works. Ben Sclair entertained us last month with some predictions for the New Year, so here’s mine concerning aviation fuels: Logic will prevail and we’ll resolve the uncertainty surrounding aviation fuels with a multiple-fuel solution that includes Mogas. Let me explain my reasoning.

It is a fact that 100LL consumption has been in decline and for many years. While some of this can be explained by a reduction in the number of hours flown annually in piston-engine aircraft, the bigger explanations are to be found at both ends of the power spectrum. At the high end, owners of heavy piston twins have moved in recent years to light jets and turbine singles such as the Pilatus PC-12, Socata TBM, and Piper Meridian. Cessna is adding to this trend, as evidenced by the grainy pictures that emerged late last year of a single-engine turboprop based on the company’s successful Mustang entry-level jet. Missionary aviation groups too are moving to all-jet-fuel fleets as 100LL becomes scarce in developing countries.

At the other end of the spectrum we have a huge array of new Light-Sport Aircraft, nearly all of which are powered by miserly engines from Rotax and Jabiru designed to operate best on 91+ ethanol-free gasoline, aka Mogas. There exist now at least two twin-Rotax aircraft available, the Italian Tecnam P2006T and the French DynAero TwinR, both of which offer a modern four-place cabin while burning 9gph (total!) of $3 Mogas per hour. With these two trends, it is only logical that 100LL consumption would decline, as evidenced by a slow decrease in the number of FBOs that offer avgas in the U.S., according to numbers we track at FLYUNLEADED. Refineries, of course, see this trend, explaining why there remain fewer than 10 that produce the fuel in the U.S. and perhaps only two in western Europe, one being Hjelmco Oil, maker also of the popular 91/96UL unleaded avgas.

With 100LL on the decline and now representing less than 0.2% of vehicle fuel made in America, it is illogical that a fuel producer would see the market for its replacement as anything greater. Replacing 100LL with an unleaded 100 octane fuel will also not change the decline in the need for that fuel, barring any sudden increase in the use of engines that require it, something that is highly unlikely. With all new products, there are major costs for development, testing, certification and distribution that must be amortized through the product’s sales over a reasonably short amount of time. Either this new “boutique” fuel must be produced in significantly greater volumes than 100LL, or it must be priced significantly higher than 100LL to compensate for these startup costs. It is therefore illogical to assume that 100LL’s replacement will be cheaper, and it is logical to assume that it will be more expensive, if any company is found to produce it, that is. Given the diminishing revenue current avgas producers must be seeing, it is logical to assume that some will leave the market, which could even include the world’s only producer of Tetra Ethyl Lead (TEL), England’s Innospec. Without TEL, of course, there is no 100LL. As avgas producers leave the market, supplies decline, driving up the costs to pilots, forcing more to give up flying … you get the picture, and it’s not pretty, but it is a logical conclusion.

With all the talk of 100LL and the efforts to find a replacement in the U.S., it is illogical not to consider existing alternatives. One of these, mentioned above, is Hjelmco’s 91/96UL unleaded avgas. While it would not be adequate for those who need 100 octane fuels, it would satisfy a very large percentage of the existing fleet of piston-engine aircraft. But it’s in Sweden, and we need it here. It’s also certified for essentially all piston-engine aircraft in Europe (most of which are the same planes flown in North America), but the FAA has chosen not to accept this European certification. That’s illogical.

The other FAA-approved, affordable and – until ethanol started contaminating our gasoline – generally available aviation fuel is the same stuff found at 160,000 gas stations across the country, Mogas, or more specifically ASTM D4814-compliant, lead-free, ethanol-free, 91+ (AKI) octane gasoline. Since it has been established that Mogas (sans ethanol) could power 70%-80% of all legacy piston-engine aircraft and essentially 100% of the new fleet of LSA ships, one should logically expect the FAA, EPA, EAA, AOPA, FOE, DOT, NATA, GAMA and other groups to enthusiastically support the expanded use of Mogas at our airports. After all, it’s cheap, has an enormous distribution infrastructure, produces exactly ZERO lead emissions and lead deposits in our engines, and it is the recommended fuel for the future generation of engines now found on modern sport aircraft. The fact that — with the notable exception of LAMA (Light Aircraft Manufacturers Association) – the nice people at the alphabet organizations mentioned above have virtually ignored Mogas as a solution to the avgas quandary is illogical at best, and irresponsible at worst.

One could speculate all day why this is the case.  Conspiracy theorists would claim that it is the strong arm of Big Ethanol quashing any attempts to allow consumers to have what they want – a choice of an ethanol-free fuel.  Or perhaps it’s the triumvirate of the EAA, AOPA and GAMA that has proclaimed “though shalt have one and only one AVGAS and it will be 100 octane”.  It might even be the lead industry’s lobby that fears the end of their existence, but that’s hardly likely.

The one factor that bureaucrats, politicians, lobbyists and the aviation alphabets ignore is the will of the consumer, who generally is a whole lot smarter than given credit.  There is a growing cacophony of them who are seeing the deleterious effects of ethanol in fuels and they are “mad as heck and aren’t going to take it any more.”  Just as the replacement — by edict — of the good-old, cheap, warm, non-toxic Edison light bulb by the Mercury Curly Fries Lightbulbs (CFLs) has resulted in hoarding of the former and disdain of the latter, so too is the damage to property and the environment caused by ethanol leading to increased calls for changes to the EISA 2007 RFS mandates that have resulted in contamination of America’s gasoline with ethanol.

Logic would lead one to conclude that lawsuits and changes to our laws should be the consequence of unpopular legislation such as EISA 2007. The many comments among the 5,000+ signers of our petition to ban ethanol in Premium gas are proof of rejection of ethanol among consumers.  A growing number of industry lawsuits opposing the EPA’s recent approval of E15 only strengthens what consumers are saying – please give us a choice to not use ethanol in our fuel!  Three such lawsuits have been filed since November from three powerful organizations: The American Petroleum Institute (API), the National Marine Manufacturers Association (NMMA), and the National Petroleum and Refiners Association (NPRA). All share the NPRA’s concern that E15 “could harm the engines owned by the millions of Americans we serve”.  Since ethanol at any level in Mogas is damaging to aircraft, one would logically expect to hear similar protests from any one of the aviation alphabets as well as the Congressional General Aviation Caucus. All one hears however is a loud echo. Ben Stein put it so succinctly, “anyone, anyone?”

At the annual meeting of the Petroleum Equipment Institute last fall, Dr. Phillip Verleger, a professor at the University of Calgary and a noted expert on the oil industry, called the U.S. mandates on ethanol production a “gimmick” devised to benefit primarily the agricultural and ethanol industries. As Verleger accurately described the situation, America’s ethanol policy is “a train wreck in progress.”  If we wish to avoid this train wreck, the unattainable mandates for ethanol must, logically, be amended. The Johnny Mercer 1954 hit tune, “Something’s Gotta Give” comes to mind.

Mogas is the safest, cheapest, most widely-available and affordable, long-term solution to most of the problems surrounding the future of aviation fuel, providing ethanol is kept out of it. That it must become one of the two fuels powering piston-engine airplanes in the future is simple logic, really.


  1. says

    PB, AVGAS sales have been dropping at about 4% the past 8 years during a time when Mogas has disappeared from our airports and ethanol has contaminated gasoline at the pumps. AVGAS sales are not dropping as a result of Mogas, but are due more to the shift of heavy twin owners to turbines and the low fuel consumption of new LSA aircraft that are becoming more popular for training fleets. Modern piston engines from Rotax, Jabiru, ULPower, SMA and others are designed using mass-produced automotive components and fuels, great news for aviation that has traditionally used boutique, low-volume products. In the future there will be two primary aviation fuels, MOGAS and Jet-A. Expect continued disappearance of 100 octane fuel and prices to climb. 100LL will probably remain for years at a high price for those who need it, but expect to pay the same as high-octane racing fuel, above $10.

  2. PB says

    Most general aviation aircraft do not need 100 octane fuel, and can operate at about 92 octane – which is the present level for the same fuel that we have now with the lead removed. However, the “market forces” sentiment of the article is germane since dividing the supply for aircraft that can use 92 octane unleaded fuel and for those that need 100 octane is another inefficiency that the supply market doesn’t want. The reason why we have just 100 octane now is due to the supply chain wanting just one type of fuel.
    This will sort itself out as long as there is a profit motive to drive supply, but $5 fuel is killing GA at the present time and the concept of $7 to $10 fuel may halve the existing fleet.
    Great article – but a difficult picture ahead.

  3. says

    Thanks for the good comments. Notice that my predictions are aimed at all the pilots who do not need a 100 octane fuel. That does not however mean that we should abandon 100LL or its replacement. As far as infrastructure is concerned, it already exists other than a small, modestly-priced fuel station. 160,000 gas stations in the U.S. now receive their fuel via trucks that drive by virtually every airport. If these contained E0 Premium, there is little doubt that many would be happy to make a quick stop at airports to unload a few thousand gallons of Mogas. Small fuel stations or even a fuel trailer can be had for well under $50,000.

  4. JS says

    Your arguments are spot on. But, (there’s always a big but) there needs to be a fuel available for the big horses that require 100 Octane fuel. Most airports have such low fuel flowage that they are not going to go to the additional expense to set up and insure a second tank to dispense a second selection of fuel. They will have to make a choice of which fuel to sell. The high dollar 100UL boutique fuel that might make it to market some day for the big horses that everyone else can also burn, the possibly more moderately priced 96UL that the vast majority of the aviation fleet can burn, or the significantly less expensive mogas that only some of the fleet can burn. It’s a no win situation for the FBOs.

    The ethanol lobby and ethanol contaminated fuels is a whole different subject. But in short, just like for pilots, alcohol and aviation should never be mixed.

  5. Randy S. says


    My fuel tanks are fiberglass and built into the fuselage and wings as many other carbon fiber aircraft. The recent change to ethanol even in premium Shell a few years back has caused a significant problems, and there’s simply no way to upgrade them. It’s time to stop subsidizing this junk and let the market shed it naturally.

  6. Ken Leh says

    It isn’t just about the engine. My auto engine powered experimental is entirely compatible with E10 and runs fine on it with its automotive injection. However I’ve seen the alcohol separate out in as little as 48 hours just sitting in the hangar when the humidity was high. A slug of separated alcohol will immediately lean out and stop the engine. Unlike sealed tanks and gas caps on injected cars, airplane fuel tanks are vented to atmosphere and take in moisture every time the temperature or pressure drops. Overnight temperature variations can do this. Flying can make it happen even quicker. It doesn’t take much moisture to cause separation.

  7. Dennis Reiley says

    It’s a good start but most automotive fuel stops consider 91+ octane to be premium. The aviation industry is way behind the automotive industry when it comes to fuel types. An average Sport/Recreational aircraft should be able to taxi up to an out of the way service station and fill its tanks. About the only thing that will keep ethanol out of aviation fuels is if the government stops subsidizing its production and we are charged its actual costs. We have only begun to see the push for ethanol fuels. (Read the history of automotive fuels from TEL to unleaded to 10% ethanol.) So until that happens plans should be made for aviation engines to use a partially ethanol fuel. That means aviation fuel systems including fuel tanks must be rust resistant like automotive fuel systems.

  8. Bart says

    As an Architect, I appreciate your engineer’s “logic”, however, as my dad used to say, “it’s pointless to use logical thinking when dealing with an illogical mind”. Therein lies the rub, there is little logic being applied to the problem of a replacement 100LL fuel for GA. Note, I said, ” a fuel”. There will NOT be two fuels! The infrastructure cost of having three fuel distribution systems on any GA ramp is simply too high. The requlatory hoops related to the storage and distribution of fuel will see to that. So, logically, there will be only two fuels, Jet A and the replacement for 100LL, whatever that is.
    You’re entirely correct about the ethanol issue, it is a gimmmick. But, having a 91 octane unleaded, unpolluted, gasoline doesn’t solve the problem. We need a single fuel that will work with the legacy engines, including the large displacement, high compression recips, and the newer LSA types, period. If that means we need a 96 octane, unleaded fuel, that FAA should approve for ALL currently operated piston engines, then LOGICALLY that’s where the emphasis should be placed. In the final analyis, FAA is the dog and fuel is the tail. Only FAA can resolve this issue. There is little doubt that most legacy engines, even the high performance ones, can run on 96 octane, unleaded fuel, with minor modifications or operational restrictions.

  9. Larry says

    Good logic, Kent, except for that part about free markets.

    Dr. Verleger has it right, ethanol production is a “gimmick devised to benefit primarily the agricultural and ethanol industries.” There’s nothing “free market” about this industry. It lives by lobbyist and is immune to desires of the consumer.

    Let’s hope the recent stirrings of protest, and the law suits, are able to establish a beachhead.

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