What is a primary consideration when selecting fuel for a specific aircraft?

Selecting fuel for a specific aircraft primarily revolves around its compatibility with the engine design. This is crucial because each aircraft engine is engineered to operate with specific fuel characteristics that affect performance, efficiency, and safety. Compatibility ensures that the fuel can properly combust within the engine’s design parameters, which helps prevent issues such as engine knocking, overheating, or even failure.

For instance, using a fuel type that does not match the engine's requirements could lead to adverse outcomes, including reduced power output or increased wear on engine components. Therefore, ensuring that the fuel is designed to work with the specific materials and combustion processes of the engine is vital for optimal operation and longevity.

While availability, cost, and brand reputation are all practical considerations, they do not take precedence over the safety and performance implications tied directly to engine design compatibility.