Fuels for Sport Aircraft: The looming crisis


Among the hundreds of forums and workshops held at this summer’s AirVenture, few concerned a matter of greater importance to sport aviation than the two forums dealing with aviation fuels.

On Monday, July 27, the EAA’s Vice President of Government Relations, Doug Macnair, led a Fuels Panel Discussion, with representatives from the EPA, FAA, GAMA, and ExxonMobil commenting on a 19-year collaborative effort to find a replacement for 100LL. Macnair and others concluded that there is no single fuel that can equal the many good characteristics of 100LL, but that environmental and political concerns over lead exposure – regardless of the miniscule amounts produced by aircraft compared to vehicles in past years – will ultimately eliminate it as a fuel.

Much discussion was focused on alternatives to avgas that would be suitable for all but the highest performance engines, but there remains much speculation over which one of a number of potential fuels this might be. Panel members recommended a dual-fuel solution initially, with alternative fuels for lower compression ratio engines now under development being offered at airports in addition to 100LL.

Ironically, there was little mention in the panel discussion of one fuel that has been available for over two decades – autogas.

The second forum dealing with this topic, titled “Fuels for Sport Aircraft: The Looming Crisis,” was a joint effort by Dean Billing, an expert on autogas and ethanol, Kent Misegades, an engineer and aviation writer, and Todd Petersen, owner of more than 150 autogas STCs for aircraft. This forum described the history of autogas as a fuel that today can power between 70% to 80% of all sport aircraft, but is rarely found at airports. Indeed, the lack of a second fuel pump for piston aircraft engines is an impediment to the dual-fuel strategy recommended by the panel, regardless whether the second fuel is autogas or something newer.

The three moderators of the second forum reported on the tenuous future of autogas as this second fuel due to government-mandated quotas on ethanol use in vehicle fuels. They gave a sobering review of the government “EISA” Act that has set a timeline for increased ethanol blending in automotive fuels, and the many issues dealing with its use in sport aircraft. They also provided details on ethanol mandates in a number of states, as well as the little-known use of BOB, or sub-octane gasoline blend stock that increasingly is delivered by refiners, a fuel that is not only forbidden for use in vehicles without the addition of ethanol, but is unsuitable for aircraft.

The moderators concluded that, given environmental pressures to eliminate 100LL and federal mandates leading to the end of a supply of ethanol-free autogas, many sport pilots may find themselves without a means to power their aircraft in the near future.

The three urged all pilots to get informed and contact their representatives in Washington, asking them to preserve a supply of ethanol-free premium autogas. They also offered their assistance in this effort. The full presentation from this forum can be found here.


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