Plane piston engines use a high octane (80/87, 91/96, 100 LL, 100/130, 108/135, 115/145) fuel that is obtained by formulating the gasoline and called aviation gasoline (“AVGAS”). Since AVGAS has a different formulation, it should not be mixed with the fuel used in jet engines.
The ratio of few and much volatile components in AVGAS is lower than the gasoline used in automobiles. This property is very important for the flights in high altitudes.
AVGAS contains a certain ratio of lead tetra-ethyl to increase gasoline burning rate. According to contained lead tetra-ethyl ratio:
- AVGAS 80/87: It is only used in engines with lower compression ratio and contains maximum 0.5 grams of lead tetra-ethyl in 4.5 liters.
- AVGAS 100/130: It is a high octane aviation gasoline. It contains maximum 4 grams of lead tetra-ethyl in 4.5 liters and maximum 1.12 grams in 1 liter.
- AVGAS 100 LL (Low Lead): It contains maximum 2 grams of lead tetra-ethyl in 4.5 liters and maximum 0.56 grams in 1 liter. It is the mostly used aviation gasoline.
- AVGAS 115/145: Generally used in military aviation.
- AVGAS is colored with a special colorant to enable pilots and maintenance teams to recognize the fuel type.
- AVGAS 80/87 is red, AVGAS 100/130 is green and AVGAS 100LL is light blue.