Avgas is an aviation fuel used in aircraft with spark-ignited internal combustion engines. Avgas is distinguished from conventional gasoline (petrol) used in motor vehicles, which is termed mogas in an aviation context. Unlike motor gasoline, which has been formulated without lead since the 1970s to allow the use of catalytic converters for pollution reduction, the most commonly used grades of avgas still contain tetraethyl lead, a toxic lead containing additive used to increase octane rating and prevent engine knocking. There are ongoing efforts to reduce or eliminate the use of lead in aviation gasoline.
An American Aviation AA-1 Yankee being refueled with 100LL avgas
Taking a fuel sample from an under-wing drain using a GATS Jar fuel sampler. The blue dye indicates that this fuel is 100LL.
An EAA Cessna 150 used for American STC certification of auto fuel
Purdue University Cessna 150M Swift Fuel demonstrator
Aviation fuels are petroleum-based fuels, or petroleum and synthetic fuel blends, used to power aircraft. They have more stringent requirements than fuels used for ground use, such as heating and road transport, and contain additives to enhance or maintain properties important to fuel performance or handling. They are kerosene-based for gas turbine-powered aircraft. Piston-engined aircraft use leaded gasoline and those with diesel engines may use jet fuel (kerosene). By 2012, all aircraft operated by the U.S. Air Force had been certified to use a 50-50 blend of kerosene and synthetic fuel derived from coal or natural gas as a way of stabilizing the cost of fuel.
An aviation fuel truck
At some airports, underground fuel pipes allow refueling without the need for tank trucks. Trucks carry the necessary hoses and pumping equipment, but no fuel.
Ground fueling of a MiG-29 from a URAL tanker (2011)
Aviation fuel storage tanks at George Bush Intercontinental Airport, Houston, Texas