What Is the Name of Airplane Fuel? ATF and Jet Fuel Explained

There are several types of aviation fuel used in different aircraft:

1. Jet A-1 — The international standard jet fuel used in most commercial aircraft worldwide. Kerosene-based with a freezing point of −47°C.
2. Jet A — Similar to Jet A-1 but with a higher freezing point of −40°C; primarily used in the United States.
3. Jet B — A wide-cut fuel (blend of gasoline and kerosene) used in extremely cold climates like northern Canada and Alaska. Freezing point is −60°C.
4. JP-8 — Military grade fuel similar to Jet A-1, used by NATO air forces.
5. JP-4 — Older military fuel, similar to Jet B, now largely phased out.
6. Avgas (Aviation Gasoline) — Used in piston-engine aircraft (small propeller planes), not jet engines. Common grade is Avgas 100LL (low lead).

Jet fuel (Jet A-1) is primarily composed of:

• Hydrocarbons with 8 to 16 carbon atoms
• Alkanes (paraffins): ~60% — both straight-chain (n-alkanes) and branched
• Cycloalkanes (naphthenes): ~20%
• Aromatic hydrocarbons: ~18% (benzene derivatives, naphthalene derivatives)
• Alkenes: minimal (less than 1%)

The aromatic content is limited (typically ≤25%) to reduce smoke and carbon deposits. Jet fuel has a carbon-to-hydrogen mass ratio of approximately 6:1 and a calorific value of about 43.2 MJ/kg.

Jet A-1 has specific properties that make it suitable for high-altitude aviation:

• Freezing point: ≤ −47°C (crucial for high-altitude flight where temperatures drop below −40°C)
• Flash point: ≥ 38°C (minimum temperature at which vapour can ignite)
• Boiling range: 150°C to 300°C
• Density: 775–840 kg/m³ at 15°C
• Energy content (calorific value): ~43.2 MJ/kg
• Low vapour pressure to minimise evaporation and fire risk
• Good thermal stability to prevent breakdown in hot fuel systems
• Lubricity to protect fuel system pumps and valves

In a jet engine (gas turbine engine), the combustion process follows these steps:

1. Intake — Air is drawn into the engine
2. Compression — A compressor increases air pressure significantly
3. Combustion — Jet fuel is injected and burned with the compressed air in the combustion chamber. The reaction: CₙH₂ₙ₊₂ + O₂ → CO₂ + H₂O + heat
4. Expansion — Hot combustion gases expand rapidly through turbines
5. Thrust — Exhaust gases exit at high velocity, producing thrust (Newton's 3rd Law)

Jet fuel's high energy density (~43 MJ/kg) and liquid state make it ideal for aviation, enabling aircraft to carry large amounts of energy in a compact, manageable form.

In India, Aviation Turbine Fuel (ATF) is refined to IS 1571 standard, which is aligned with the Jet A-1 specification. ATF prices in India are regulated and revised monthly by state-owned oil companies. ATF constitutes roughly 30–40% of airline operating costs in India. The Bureau of Energy Efficiency (BEE) categorises ATF as a high-energy transport fuel. India's ATF is primarily supplied by Indian Oil Corporation (IOC), Bharat Petroleum (BPCL), and Hindustan Petroleum (HPCL).