What fuel is used in an aeroplane?

Let’s go in detail about the types of fuel used in airplanes:

1. Definition of Aviation Fuel

Aviation fuel is a specially formulated fuel used to power aircraft engines.

It must provide high energy content, stability, and safety at extreme altitudes and temperatures.
The type of fuel depends on the engine type: piston engines or jet engines.

2. Types of Aircraft Engines and Their Fuel

A. Piston Engines (Reciprocating Engines)

Used in small propeller-driven aircraft.
Fuel Type: Aviation gasoline (Avgas).
Characteristics:
- High-octane petrol, usually 100LL (Low Lead) or 100/130
- Designed to prevent knocking at high compression ratios
- Stable at varying temperatures and pressures

Example Aircraft: Cessna 172, Piper PA-28

B. Jet Engines (Turbine Engines)

Used in commercial airliners, military jets, and business jets.
Fuel Type: Jet fuel (kerosene-based).
Common Grades:
1. Jet A / Jet A-1:
  - Most widely used in commercial aviation
  - Flash point: ~38°C
  - Freezing point: Jet A-1 ~ −47°C (Jet A ~ −40°C)
  - Kerosene-based, refined for clean combustion
2. JP-8 / JP-5:
  - Military jet fuels with additives for anti-icing, corrosion prevention, and stability

Example Aircraft: Boeing 747, Airbus A320, F-16 fighter

C. Turboprop Engines

Use kerosene-based jet fuel (Jet A or Jet A-1).
Combines features of propeller and jet propulsion.

Example Aircraft: ATR 72, Bombardier Q400

3. Key Properties of Aviation Fuel

Property	Importance
High Energy Density	Provides sufficient thrust or lift
Low Freezing Point	Functions at high altitudes and cold temperatures
High Flash Point	Safety during storage and handling
Detergent & Anti-Corrosion Additives	Keeps engines clean and protects fuel system
Stable Combustion	Prevents knocking in piston engines and ensures smooth jet operation

4. Difference Between Avgas and Jet Fuel

Feature	Avgas	Jet Fuel
Engine Type	Piston engines	Jet / turbine engines
Base	High-octane petrol	Kerosene
Octane Rating	100LL, 100/130	N/A (cetane rating for military JP fuels)
Lead Content	Contains lead (low-lead 100LL)	Lead-free
Energy Density	Moderate	High
Freezing Point	Moderate	Very low (-47°C for Jet A-1)

5. Summary

Small piston aircraft: Use Avgas (aviation gasoline)
Jet or turbine aircraft: Use Jet fuel (kerosene-based, Jet A, Jet A-1, JP-8)
Aviation fuel is formulated for high energy, stability, safety, and cold-weather performance.
Using incorrect fuel can cause engine failure or accidents, so fuel type is strictly regulated.

💡 Tip:
Jet fuel is similar to kerosene, while Avgas is high-octane petrol with additives. Commercial airliners almost exclusively use Jet A or Jet A-1.