A major new rule released by the US Environmental Protection Agency may force a number of airports to limit piston aircraft operations to restrict lead emissions from avgas fuel.

Van Nuys in Los Angeles, Centennial near Denver, Phoenix Deer Valley and Orlando Sanford were among the 135 sites estimated to have annual lead emissions above 1t. Avgas is the only leaded fuel still used in the USA due to the octane boost it provides.

Those airports now must monitor local air quality. If it exceeds accepted standards they will need a corrective plan by 2013 and action by 2017.

"I think when each of those airports do their own data based on real data, some of those will fall off," predicts Walter Desrosier, vice-president of engineering and maintenance for the General Aviation Manufacturers Association. The Environmental Protection Agency looked at all GA operations, he says. "The data for landings and take-offs doesn't differentiate between pistons and turbine jets."

The new standards lower the allowable amount of lead to one-tenth of previously accepted levels, while manufacturers and regulators are contemplating which fuel will replace avgas.

"I think this is a very good step by the EPA to continue to protect public health," Desrosier adds. The biggest obstacle is not designing a new engine, he says, but keeping the existing high-performance piston fleet in the air.

Earl Lawrence, vice-president of industry and regulatory affairs, says: "We've had to fight on a state-by-state basis to try to preserve a supply that does not contain ethanol or other additives not approved for aviation use." He adds that, with the agency's new rule, "we're also seeing the potential for restrictions on aircraft running on leaded fuel in a given area".

Source: Flight International