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Many airplanes could run on regular gasoline — if it didn't have ethanol added to it. Photo by John Ryan.

Many airplanes could run on regular gasoline — if it didn't have ethanol added to it. Photo by John Ryan.


Unleaded Fuel Hard To Find For Airplane Pilots

John Ryan

Half of all the lead pollution in America's air comes from the exhaust of small airplanes. Here in Washington, thousands of small planes still burn leaded fuel. That was one of the findings of our "Flying the Leaded Skies" investigation in January.

Most of those planes could be running on unleaded fuel, but almost none of them do. KUOW's John Ryan found out why.



Steve Carkeek starts his engine on the tarmac at Boeing Field in Seattle.

Carkeek: "We're sitting in my airplane, the old green slug. It's a Cessna 172. It was manufactured in the early 1960s."

It's got four seats, three wheels, a single engine.

Carkeek: "It's for recreation primarily. I have a daughter who lives in Portland. I have relatives who live up on Friday Harbor."

Big airplanes tend to have jet engines.

(Music: "Jet Airliner" by Steve Miller Band.)

Big old jet airliners run on jet fuel. It's an unleaded fuel. Jet exhaust isn't so great for the environment, but at least it doesn't have lead.

Only small, piston–engine planes, like the old green slug, use the leaded fuel known as avgas.

Carkeek: "There's a readily available solution to the lead problem, a solution that's applicable to 80 percent of the airplanes parked out here right now."

For most of his quarter–century as a pilot, Steve Carkeek says he's managed to avoid using leaded fuel altogether.

Carkeek: "I could go to any gas station, buy 87 octane car gas, put it in the barrel, take it to the airport, fill the airplane and everything was fine."

That's right. Most of the planes that send lead into the air can run on plain ol' gasoline. Pilots call it mogas. That's short for motor gasoline.

Bertorelli: "So–called mogas was a popular fuel in the 80s. But it fell out of popularity for two reasons."

Paul Bertorelli is a pilot and editor in Florida. He edits the aviation website He says few airports sell mogas, even though a gallon of mogas tends to cost a dollar or two less than a gallon of avgas.

Bertorelli: "On the other hand, the airport has to put in the tanks and pipes. So they end up with a dual fuel system, and it's kind of expensive. Some will do it, some won't."

Here in Washington, out of more than 130 public airports, only three sell unleaded mogas. They're in Pullman, Walla Walla and on Whidbey Island. That's according to

A Congressional mandate has also fueled the decline of mogas as aviation fuel. That mandate made most street gasoline unfit for aviation: In 2007, Congress decreed that billions of gallons of ethanol be added to the nation's gasoline supply each year.

The law benefited corn growers. It was supposed to reduce air pollution, too, but the environmental record of corn–based ethanol is mixed at best. One unintended consequence was that many airplane pilots switched from unleaded to leaded fuel to avoid harming their engines with ethanol.

Carkeek: "Because of the way it interacts with some components in aircraft fuel systems — the ethanol itself — there's some plastic and rubber parts that don't do well with ethanol."

Steve Carkeek found a way to keep using unleaded fuel. When he lived in South King County, he found a distributor in Auburn who could sell him gasoline before adding ethanol to it.

Carkeek says it was moving to Seattle last summer that made him a worse polluter.

Carkeek: "Since the airplane is parked here on Boeing Field, and because I'm not permitted to fuel my own airplane, yes, I have to run leaded avgas in it."

(Sound: cockpit radio.)

When Carkeek leased a parking spot for his plane at Boeing Field, he was told he could only use the leaded fuel sold at the airport.

Carkeek: "I'm certainly disappointed that I'm not able to fuel my airplane the way I've been fueling it for the last, what, 25 years."

KUOW looked into the regulations at Boeing Field. We found they do allow pilots to use their own fuel, if they get a permit.

That's contrary to what the airport's leasing official told Steve Carkeek.

As we were reporting this story, Boeing Field officials changed their tune. They gave Carkeek the go–ahead to apply for a permit to pump his own fuel at the airport. So it looks like at least one pilot will get to stop using leaded fuel very soon.

But what about the airplanes that need a higher–octane fuel than you can find at a gas station? Tomorrow, we'll explore what's keeping those planes flying on leaded fuel.

I'm John Ryan, KUOW News.

Leadbelly: "Turn your radio on. Turn your radio on. Turn your radio on, so you hear what's going on."

© Copyright 2012, KUOW

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