Which Fuel Is Used in Aeroplanes? Aviation Turbine Fuel Explained

#What aviation turbine fuel is

ATF is a kerosene fraction, distilled between roughly 150 °C and 250 °C, then refined and additised to a specification far stricter than domestic kerosene.

Property	Typical Jet A-1 value
Freezing point	Below −47 °C
Flash point	Above 38 °C
Density at 15 °C	0.775–0.840 kg/L
Calorific value	~43.15 MJ/kg
Sulphur	Below 0.3%, usually far less

Regional variants:

• Jet A-1 — the international standard, freezing below −47 °C
• Jet A — mainly US domestic, freezing below −40 °C
• Jet B — a wide-cut blend for extreme cold, rarely used because of its volatility
• JP-8 / JP-5 — military equivalents, JP-5 with a higher flash point for aircraft carriers

#Why kerosene rather than petrol

#Safety

Flash point is the deciding property:

Fuel	Flash point
Avgas / petrol	~−43 °C
Jet A-1	~38 °C

Petrol produces ignitable vapour at any ordinary temperature, so a tank of it always has a flammable vapour space above the liquid. Kerosene does not at normal conditions. In an aircraft carrying tonnes of fuel in wing tanks, that difference is decisive — it is why a survivable accident often stays survivable.

#Energy per litre

Aircraft tank volume is fixed by the airframe, so energy per litre matters more than energy per kilogram in tank sizing. Kerosene is denser than petrol and delivers roughly 5% more energy per litre.

#Low-temperature behaviour

At cruising altitude the outside air is around −55 °C, and fuel in the wings cools steadily on long flights. Jet A-1's freezing point below −47 °C keeps it flowing. Freezing point in this context means the temperature at which wax crystals begin to form and block filters, not the temperature at which the whole tank solidifies.

#Lubricity

Jet fuel lubricates the fuel pumps and control units it passes through. Petrol is a poorer lubricant, and severe hydrotreating that removes sulphur also removes lubricity — which is why lubricity improvers are added.

#Turbine tolerance

A gas turbine burns fuel continuously in a combustor rather than in timed cylinder explosions, so it does not need petrol's anti-knock properties. It needs clean, steady, high-energy combustion, which kerosene provides.

#The additives

Jet fuel is not simply distilled kerosene:

• Anti-icing (FSII) — prevents dissolved water freezing into ice crystals that block filters
• Static dissipator — prevents dangerous static charge build-up during high-rate fuelling
• Antioxidants — prevent gum formation during storage
• Metal deactivators — suppress catalytic degradation by trace metals
• Corrosion inhibitors / lubricity improvers
• Biocides — control microbial growth at the fuel–water interface in tank bottoms

That last one is a real operational issue: microbes living in water settled at the bottom of a tank produce sludge that blocks filters and corrodes tank structure.

#In India specifically

ATF at Indian airports is supplied mainly by Indian Oil, Bharat Petroleum and Hindustan Petroleum, refined domestically to Jet A-1 specification. ATF is a significant cost item for Indian carriers, partly because of the tax treatment applied to it, and fuel typically represents around a third of an airline's operating cost.

#Sustainable aviation fuel

SAF is chemically similar to conventional jet fuel but made from used cooking oil, animal fats, agricultural residues, or synthesised from hydrogen and captured carbon dioxide. It is certified for blending, currently up to 50% in most approved pathways, and burns in existing engines with no modification.

It is the main decarbonisation route available to aviation, because batteries are far too heavy for long-haul flight — the energy density gap is roughly fifty to one — and hydrogen would require entirely new airframes.

For what kerosene actually is and where it sits in the barrel, see is kerosene a fossil fuel. The propellant question for spaceflight is a different problem entirely — see rocket fuel explained.

#The compact answer

Aeroplanes with jet engines use aviation turbine fuel (ATF), a highly refined kerosene sold to the Jet A-1 specification. It is preferred over petrol because it is far less volatile and therefore safer, has a higher energy content per litre, and has a very low freezing point suited to high altitudes. Small piston-engined aircraft use aviation gasoline (avgas) instead.