What is aircraft fuel?

All civil aviation kerosene is, essentially, the same product, but it goes by different names depending on the standard that certifies it. Jet A-1 meets both the American ASTM D1655 standard and the British DEF STAN 91-091, with a maximum freezing point of −47°C, and it's what an aircraft refuels with at any airport in Europe, Asia, Africa, Oceania or Latin America. Jet A, which is only distributed in the United States and some Canadian airports, is made with a freezing point of −40°C, sufficient for domestic flights and somewhat cheaper to produce. Russia and other countries of the former Soviet bloc use TS-1, a lighter kerosene designed for cold climates. Western militaries call Jet A-1 with additives JP-8, and navies use JP-5, which is less flammable, on aircraft carriers.

At an airport, confusing fuels can be deadly, so the systems are color-coded. Jet A-1 trucks, hydrants and tank caps carry a black label with white letters, and pressure refueling couplings have a diameter that doesn't fit the mouth of an avgas tank. Aviation gasoline, for its part, is identified in red and is dyed blue (100LL) or green (100). In light aviation the pilot checks the color and smell of a drained sample before every flight, precisely to detect that kerosene hasn't been loaded into a piston engine, a mistake that has caused accidents.

A large airport consumes quantities that can only be moved by pipeline: Heathrow or Madrid-Barajas receive kerosene by pipeline from refineries or port terminals, store it in tank farms with capacity for several days and distribute it through a network of hydrants buried under the ramp. A Boeing 777-300ER can load up to 181,000 L on a long-haul flight and an A380, about 320,000 L, figures that make tanker trucks impractical at contact gates. Every liter that reaches the wing has gone through at least three filtering stages and a free-water check.

Kerosene is bought by the ton in regional markets (Rotterdam, Singapore, the U.S. Gulf Coast) and its price tracks oil with its own spread; at the end of 2024 it was around 800-900 dollars per ton (as of December 2024). For the operator, weight matters, not volume: a density of 0.8 kg/L means that 100,000 L is 80 t, and that mass determines how much the aircraft can carry and how much extra fuel it burns just to transport the fuel itself.