English: AVGAS 100 LL Petron Leaded fuel 190 liters ASTM D 910-11 - Avgas[1] (aviation gasoline, also known as aviation spirit in the UK) is an aviation fuel used to power piston-engine aircraft. Avgas is distinguished from mogas (motor gasoline), which is the everyday gasoline used in cars and some non-commercial light aircraft. Unlike mogas from the mid-1970s era onward to allow the adoption of platinum-content catalytic converters for pollution reduction, avgas still contains tetraethyllead (TEL), a toxic substance used to enhance combustion stability. crew and pilots in identifying and distinguishing the fuel grades. 100LL The most commonly used aviation fuel is 100LL, that is, "low lead". It is dyed blue and contains a relatively small amount of tetraethyllead—though the amount is greater than what was contained in many automotive grades of leaded fuel before such fuel was phased out.