As 2014 drew to an end, a lawsuit against a group of California FBOs and fuel distributors filed three years earlier by the Center for Environmental Health (CEH) over sale of leaded avgas was settled through an agreement preventing what could have resulted in grounding almost all piston-powered aviation in the state.

While the National Business Aviation Association is almost always identified with issues affecting the operation of turbine-powered business aircraft, more than 1,000 of its member companies operate piston-engine light planes to support their business travel.

Whoa. Wait a minute. Stop the presses! Wasn’t unleaded automobile gasoline (so-called “pump gas”) approved for use in some engine/airframe combinations years ago, at least for the smaller piston engines, e.g., the Lycoming O-360 installed in thousands of Cessna 172s and other light planes?