Image of shell station by Jose Luis Hermida
| Fuel | Engine Type | Common Uses |
| Petrol | Spark-ignition engine | Cars, motorcycles, SUVs |
| Diesel | Compression-ignition engine | Trucks, buses, tractors, generators |
| Avgas | Aircraft piston engine | Small propeller aircraft |
| Jet A / Jet A-1 | Turbine engine | Passenger jets, business jets, turbine helicopters |
If you've ever wondered why a Boeing 737 uses a different fuel from a Cessna, or why a diesel truck can't run on petrol, you're not alone. One of the most common questions in aviation and transport is: What is the difference between Jet A, Avgas, diesel and petrol?
Although all four are refined from crude oil, each is designed for a different type of engine. Using the wrong fuel can seriously damage an engine and, in aviation, could create a major safety risk.
Petrol (Gasoline)
Petrol is the fuel most people are familiar with. It is used in spark-ignition engines, where spark plugs ignite the fuel-air mixture.
Common petrol-powered vehicles include:
- Passenger cars
- Motorcycles
- Small vans
- SUVs
Petrol burns quickly, allowing engines to produce high revolutions per minute (RPM), making it ideal for lighter vehicles that prioritize speed and acceleration.
Diesel
Diesel is heavier and contains more energy per litre than petrol. Unlike petrol engines, diesel engines do not use spark plugs. Instead, they compress air until it becomes extremely hot, causing the diesel fuel to ignite.
Diesel is commonly used in:
- Trucks
- Buses
- Tractors
- Excavators
- Generators
- Construction equipment
Because diesel engines produce high torque, they are better suited for pulling heavy loads and operating over long distances.
Aviation Gasoline (Avgas)
Avgas stands for Aviation Gasoline. While it shares similarities with petrol, it is specially refined for piston-engine aircraft operating at high altitudes and under demanding conditions.
Aircraft that commonly use Avgas include:
- Cessna 172
- Piper Cherokee
- Beechcraft Bonanza
- Robinson R22 helicopter (piston version)
Avgas provides reliable engine performance and helps prevent engine knocking during flight.
Jet A (Jet A-1)
Jet A and Jet A-1 are kerosene-based aviation turbine fuels used by aircraft equipped with jet or turbine engines.
Aircraft using Jet A or Jet A-1 include:
- Boeing 737
- Airbus A320
- Embraer regional jets
- Business jets
- Turbine helicopters
- Military transport aircraft
Jet A-1 is the international standard and has a lower freezing point than Jet A, making it suitable for long-haul flights at high altitudes where temperatures can fall well below freezing.
Is Jet A the Same as Kerosene?
Jet A is kerosene-based, but it is not the same as ordinary household kerosene.
Aviation fuel must meet much stricter international quality standards for:
- Purity
- Water content
- Freezing point
- Flash point
- Thermal stability
- Contamination control
These standards ensure aircraft engines operate safely under extreme conditions.
Why Don't Aircraft Use Diesel or Petrol?
Image of shell station by Robert walker🇺🇸
Different engines require different fuels.
A commercial jet's turbine engine is specifically designed to burn Jet A or Jet A-1 efficiently. A piston-engine aircraft requires Avgas because its combustion system depends on spark ignition. Trucks and construction equipment use diesel because compression-ignition engines generate high torque, while passenger cars typically use petrol for smoother, higher-speed performance.
Using the wrong fuel can damage the engine and may prevent it from operating safely.