November 1, 2008
By Dave Hirschman
Pilots have been forewarned of the imminent demise of leaded avgas for many, many years and the blue fuel is still plentiful. So it’s easy to
November 1, 2008
By Dave Hirschman
Pilots have been forewarned of the imminent demise of leaded avgas for many, many years and the blue fuel is still plentiful. So it’s easy to dismiss talk of its looming disappearance now as alarmist rhetoric.
But regulatory and market forces are combining in powerful new ways that may someday force 100LL into extinction. And general aviation companies, including engine and airframe manufacturers, electronics, and petroleum firms, are taking steps to prepare new products designed to allow piston airplanes to keep flying into the future.
“After 20-plus years of research, no silver bullet replacement fuel has yet been found to satisfy the needs of the entire general aviation fleet,” said Rob Hackman, AOPA’s senior director of regulatory affairs. “So a second option that appears more likely would include some sort of engine modification for a portion of the fleet in addition to an unleaded fuel. It remains to be seen whether a bolt-on, FAA-certified, aftermarket solution will become available at a realistic price. AOPA members are the end user, and we’re going to continue to make sure their interests are protected. Whatever the industry agrees upon as a replacement to 100LL, it’s got to be safe and legal for the entire fleet to use and allow as much time as needed for the industry to transition.”
The regulatory threats to aviation fuel currently come from two primary sources: a lawsuit filed by the Friends of the Earth that compels the Environmental Protection Agency to collect more data on possible damage caused by lead emissions; and possible changes to the federal Clean Air Act that would lower the ambient lead level in the atmosphere.
Long-term exposure to high levels of lead has been shown to cause or contribute to a variety of serious medical conditions. But lead levels dropped substantially after cars switched to unleaded fuels in the 1980s, and avgas emissions are still well within allowable levels.
Any regulatory changes that affect the future availability of avgas are likely to take place gradually, however.
The greater, and more immediate, potential dangers to GA fuel supply are economic.
Avgas comes from the cream of the refining crop, and it must be segregated from unleaded fuels throughout its production and transportation processes. Avgas is costly to produce and cumbersome to deliver—and its market share is dwindling.
In the 1960s when many airliners were still propelled by piston engines, leaded avgas accounted for about 10 percent of the total U.S. gasoline supply. Now, avgas accounts for less than 1 percent, and that percentage is shrinking as demand for auto fuel rises.
U.S. refineries produce about 250 million gallons of avgas annually. That may sound like a lot, but it’s less than a single day’s output of auto fuel.
In the 1960s, FBOs commonly sold two or even three kinds of leaded avgas: one dyed red for low-compression engines, another blue for most others, and a super-high-octane purple fuel for the most powerful piston engines.
Now, airport fuel storage facilities are built to accommodate just one kind of fuel for piston aircraft—100LL, the blue kind. Although some airports may still have facilities to handle unleaded auto fuel, it’s unlikely that any new facilities will be built to accommodate more than one avgas.
“Given today’s infrastructure and economics, the industry can’t support two fuels for piston aircraft engines,” said Hackman.
No new refineries have been built in the United States for more than 30 years, and existing ones are operating at or near capacity. Fat profit margins for refineries producing auto fuel, jet fuel, and heating oil make their owners less inclined to go through the contortions necessary to produce leaded avgas.
And since handling leaded fuel is a cumbersome process and the future of avgas is uncertain, fuel distribution firms are increasingly reluctant to bear the expense of replacing or updating aging infrastructure dedicated to the handling and distribution of avgas.
The economics of the piston aircraft fleet come down to two numbers: 70 and 30. Seventy percent of the aircraft engines today could fly just fine on unleaded fuel, and unleaded fuel STCs are currently available for most of them. Cherokees, Skyhawks, Cubs, Champs, and many others use low-compression engines that could most likely make the switch to unleaded fuel with the stroke of a pen. But those airplanes only account for about 30 percent of current avgas sales.
The flip side of the equation is that 30 percent of today’s piston fleet would require significant modifica