Tomorrow's Avgas: Mogas or Diesel?

Few would dispute that the days of leaded avgas are numbered. Representing less than 0.2 percent of the total refined fuel sold annually in the U.S., sales of this ‘boutique’ fuel have been dropping by approximately 4 percent per year for the past decade.

This is due both to a reduction in hours flown by piston aircraft, a new generation of more fuel-efficient planes, and the continued transition from large-displacement piston aircraft to turboprops and jets. Add to this its near disappearance outside North America and Europe, increasing pressure from EPA to end the last use of leaded fuel, and our dependence on the last producer of Tetra Ethyl Lead (TEL), England’s Innospec.

Alternatives In The Making

Over in Europe, where I attend the great AERO Friedrichshafen annually, the continent’s largest general aviation trade show, the situation is anything but bleak. In Europe, higher prices for avgas and more severe environmental regulations forced airport and aircraft owners years ago to seek alternative fuels and develop more fuel-efficient aircraft.

Examples are the dozens of manufacturers of highly aerodynamic aircraft there, most powered by the very popular 5 gph mogas-burning four-stroke motors from Austria’s Rotax, a division of Canada’s BRP. Many of these aircraft are exported to the U.S. under the Light Sport Aircraft (LSA) category, the only segment of the GA industry that has experienced continued growth in the past few years.

At this year’s AERO, quite a few of these European manufacturers of light aircraft displayed mockups or prototypes of larger four-seat single, light twins, and even cabin-class twins.

In summary, every piston aircraft engine on display, from a 29-hp single cylinder two-stroke motor from Italy’s Poloni, to the 400-hp jet fuel-burning diesel from Austro Engines, was designed to operate on either mogas or jet fuel. These included spark-ignition mogas engines from traditional U.S. makers Continental and Lycoming, as well as a high-performance diesel engine from Continental aimed at market entry for the end of 2012.

Austria’s Diamond Aircraft attracted great attention for its sleek DA-42 and new 5-7 seat DA-52 twins, both powered by the latest jet fuel diesel engines from Austro Engines, a division of Diamond.

A Multi-Fuel Environment

One gained the clear impression from attending AERO 2012 that the inevitable end to leaded avgas in Europe is a non-issue. 100LL there is only one component of a multi-fuel environment that includes leaded avgas for the dwindling fleet that requires it, mogas for the vast majority of light aircraft and next-gen engines up to about 200-hp, and jet fuel for diesels that start around 200-hp.

With the vast majority of legacy aircraft and most new aircraft capable of burning mogas today, the risk that a sudden end of 100LL might devastate the GA industry is unlikely. More likely is a continued decline in 100LL and increased use of mogas, and eventually jet fuel in new aviation diesel engines.

Still lacking however are avgas companies willing to supply airports with aviation-grade mogas as their counterparts in Europe have done for years. Consumers like choices, and aviation fuel should be no exception. Europeans have figured this out, and as a result today enjoy a vibrant aircraft and engine manufacturing industry that once was America’s claim.

about the author

Kent Misegades is responsible for aviation & marine sales for fuel system manufacturer U-Fuel of Elk Mound, WI. An aerospace engineer, he has been a pilot since 1973, is a director of the Aviation Fuel Club, and is president of EAA Chapter 1114 in Apex, NC.