What type of fuel is primarily used in piston engine aircraft?

The correct answer is aviation gasoline (AVGAS), which is specifically formulated for use in piston engine aircraft. AVGAS is designed to provide the right combustion characteristics necessary for the efficient operation of piston engines. It has a high octane rating, which prevents engine knocking and promotes better performance and efficiency. The two most common types of AVGAS used in piston aircraft are 100LL (low lead) and 100 octane fuel.

Piston engines operate differently than turbine engines, which typically use jet fuel, making AVGAS the preferred choice for the majority of general aviation piston-powered aircraft. The fuel's specific properties, such as its volatility and combustion quality, are tailored to meet the operational demands of these engines, ensuring optimal performance and reliability during flight.

The other options, while used in aviation, do not match the requirements for piston engine operation as effectively as AVGAS does. Jet fuel is used in turbine engines, diesel fuel is primarily for diesel engines, and while biofuels are being explored, they’re not the standard type of fuel for piston engines at this time.