Avgas vs Jet Fuel
Production of aviation fuel falls into two categories: fuels suitable for turbine engines and fuels suitable for piston engine aircraft. There are well defined international specifications for both grades.
Aviation gasoline commonly known as Avgas is used in piston engine aircraft where the emphasis is on anti-lock characteristics. The fuel must give satisfactory performance under two quite different conditions:
- The rich mixture (i.e. high fuel/air ratio) condition required for higher power during take-off
- The weak mixture which permits economical cruising
Jet fuel used for turbine engines must remain pumpable at low temperatures, meet definite limits in terms of density and calorific value and burn cleanly and remain stable when heated to high temperatures.
To meet these requirements, aviation gasolines, and in particular the higher performance grades, have to be almost 'tailor made' from three or four selected components, using formulations that can vary little from batch to batch.
There are stringent requirements in respect of minor contaminants (e.g water and particulate matter) for all grades of aviation fuel.
After production, aviation grades are identified by batch numbers. Only when batched and certified is the product ready to start its journey through the supply logistics network from refinery to airport storage.