Last week, the FAA issued a report on its plan to replace 100LL with an unleaded alternative. The goal of the new Unleaded Avgas Transition Aviation Rulemaking Committee is to develop a entirely new fuel to replace 100LL. After attending a presentation at Santa Monica’s Museum of Flying this weekend, I’m wondering why.
The presentation was held by Lars Hjelmberg, owner of Hjelmco Oil – a company from Sweden that has been producing unleaded aviation fuels for more than three decades. The most widely distributed version, 91/96 UL, has been available since 1991. Since then, millions of flight hours have been flown in many different types of airplanes using this fuel, according to Hjelmberg. 91/96 UL is available today at more than 70 different airports in Sweden.
In addition to being unleaded, there are other benefits to Hjelmco’s 91/96 UL over 100LL, according to the data presented by Hjelmberg. The emissions released into the air are dramatically lower with this fuel than with 100LL. It is apparently even 35 time more pure than car gas on selected environmental parameters. Hjelmberg also claims that the airplanes that have been using 91/96 UL fuel experience better performance and the engines that normally require a 2,000-hour TBO have been able to reach 3,000 hours. In addition, 91/96 UL is “100 percent mixable with leaded avgas” according to Hjelmberg, so it could conceivably simply be filled directly into the old 100LL tanks. And, unlike 100LL, 91/96 UL can use the same distribution methods as mogas (car fuel), so it’s less expensive to transport.
Cost-wise, the product has been able to compete with 100LL. Hjelmberg claims the cost for the unleaded fuel is generally less because of lower taxes and because of the lack of lead, which has become extremely expensive with only one supplier available. Kristianstads Flygklubb, a flying club in southern Sweden, sells both fuel types for the same price. And if the product would become more accepted in the industry and production rates increased, the cost would likely decrease.
The fuel complies with U.S. standard ASTM 910 (the same as for 100LL) and has been approved specifically by Lycoming (as early as 1995) and Continental for many of its engine models. In May of this year, Cessna released a service letter approving most Cessna 172s and Cessna 177s for the use of Hjelmco 91/96 UL and another European unleaded fuel called UL91 based on ASTM D7547. Unfortunately the service letter only applies to airplanes operated in Europe.
The European Aviation Safety Agency (EASA) has also issued a safety information bulletin, 2010-31, which approves the use of Hjelmco 91/96 UL in “orphaned” airplanes – those whose manufacturers are no longer available to modify the pilot’s operating handbooks – that use fuels that qualify under certain standards, including ASTM 910.
In order to use this fuel, the only requirement for 70 percent of general aviation piston airplanes is to use an oil that contains certain additives, such as Shell’s 15W50, W80Plus or W100Plus, according to Hjelmberg. For an additional 20% of the fleet, mostly light-sport airplanes, the fuel can be used with no special requirements. But for the remaining 10 percent, it’s a little bit more complicated. Turbocharged, higher horsepower engines and “special” airplanes such as warbirds, can’t use the fuel without modifications. But there are solutions out there that would allow these operators to use the 91/96 UL as well. Unfortunately these modifications would be quite costly, but if the FAA is going to spend years and millions of dollars, why not take that money and give it to these airplane owners instead? The money could also go to new fuel stations, in which case there could be a transition period when both 100LL and unleaded fuels are available.
In addition to the issues that apply to about 10 percent of the GA fleet, there is one thing that concerns me as a user. Because Swedish law requires that no dyes are added to unleaded fuels, the 91/96UL is clear, so there is no way for the pilot to verify that the correct fuel type exists in the tanks. This should, however, be an easy problem to solve by adding some dye, though it may take several years and piles of paperwork to get such a modification through the authorities.
I don’t know much about the politics of fuel, but with the decades of testing and the approvals that have gone through EASA, I don’t see why the FAA couldn’t approve this fuel for use in the U.S. If the benefits that Hjelmberg claims are true I would think that most airplane owners would be happy to use this fuel. According to Hjelmberg, there are four avgas producers in Europe, three of which offer unleaded fuel. Hundreds of airports in Europe already have unleaded fuels available. If we’re going to transition to unleaded, why reinvent the wheel?
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"I don’t know much about the politics of fuel"
Nor, evidently, about the economics or physics. Whatever replaces 100LL has to completely replace it. Airports are set up to pump one piston fuel, not multiple fuels. We can't just abandon airplanes that need higher octane. If nothing else, Swift and GAMI fuels meet this basic requirement.
Cleaner! Faster! Longer lived engines! How about a little documentation on these claims instead of just reprinting Mr. Hjelmberg's press release, including this laughably meaningless statement, "It is apparently even 35 time more pure than car gas on selected environmental parameters. "
There is a clear reason high octane is required. 100LL is an excellent fuel, reasonably high octane, clean, good energy density, stores for years, and it is capable of reliable all weather operation in nearly all aviation engines. Let's consider the modern Cirrus turbo as an example. The use of a lower octane unleaded fuel, while possible, would require significant modifications (to achieve FAA mandated levels of detonation resistance) . Those modifications could include a significant reduction in output and the resulting unacceptable performance loss. Or they could require a much larger engine with the same output as the original engine. There is no magic here, it's one or the other. Yes, I know there are technologies that enable lower octane use in conventional aircraft engines without detonation. Those technologies involve sudden reduction of ignition timing, and the resultant loss of HP. Not, exactly what I want on a "hot, high and heavy" day. Yes, there are modern engine designs that can run low octane, with high manifold pressures and high loads (think Ford Ecoboost, direct injected, turbocharged engines) . That technology is not easily adaptable to conventional aircraft engines.
Part of the problem is there are suitable replacements such as the GAMI fuels but you got orginizations sticking thier noses into it looking to make a buck off of it and prolonging the implementation. The GAMI fuel is appealing because it does not require special refineries.
To Mr ? 100 LL
go the webb page of Hjelmco and download the presentation and give your opinion. A dual fuel solution has been explained.
Further having an AVGAS 35 times more pure than car gasoline is a very good argument against those that claim that GA is polluting. Usually the people claiming so travel by car.
Car gasoline may contain toxic components such as benzene, (known to cause
blood cancer), n-hexane (is a development-, neuro-, reproductive- and respiratory toxicant) etc.
Producing an AVGAS without these toxic components are desirable and when possible such as in our fuels - we feel this is fine for everyone.
Further ..... lead is not the real toxic agent in AVGAS it is the mandatory scavenger in about the same amounts of lead. Take a look at dibromoethane...
As a producer of AVGAS the requirements for handling that component is
even more stringent than TEL.
For documentation about the environmental qualities of our fuels pls see our webb page --- a lot of information are in English and for swedish you may use google translate.
We need to follow Brazil's lead by switching aircraft over to ethanol, which is 106 octane ( www.AlcoholCanBeAGas.com ). This could be used in our aircraft easily, just like they already do in Brazil. Fuel can be produced for about $1.00 / gallon from any plant material waste, like grass clippings, mesquite seed pods, or cattails (up to 10,000 gallons / acre!).
There is even a compact unit ( www.MicroFueler.com ) about the size of a refridgerator, that produces 35 gallons of ethanol ever 3 days automatically, with only a water hose and power connection, bulk sugar, and yeast.
Not only can it power internal combustion engines up to 18:1 compression ratios without pinging. It can also power turbine engines with almost zero pollution, it actually cleans the air! Since ethanol already contains oxygen, fuel consumption decreases above 12,000' over avgas, with a power increase.
Dragsters and race cars have used alcohol for years for the increased octane (pinging) and safety factor. Gasoline has fumes that spread out on the ground that are very explosive, alcohol evaporates safely into the atmosphere. Gasoline flames up when hit with water, alcohol is dilluted and flames go out immeadiately. Boaters use alcohol stoves to prevent explosive fumes in their bilges.
The astronaut Gordon Cooper, once flew an unmodified NASA T-38 from Indianapolis to Houston when he was called back on an emergency to substitute for the Apollo 10 Commander. Jet fuel was unavailable, so he called the race track to deliver him alcohol to fly his jet back.
Don't forget the Not-Invented-Here syndrome.
I'd buy this gas if it was available for my Geronimo!
