When routing a fuel line between two rigidly mounted fittings, what should be done?

When routing a fuel line between two rigidly mounted fittings, incorporating at least one bend is essential. This practice allows for accommodating any potential movement or thermal expansion that may occur between the fittings due to engine vibration or changes in temperature. By including a bend, the fuel line can flex slightly without inducing stress or strain on the fittings, which can lead to leaks or failure over time.

Additionally, a bend can help in reducing the stiffness of the line, allowing it to absorb vibrations rather than transmitting them directly to the fittings. This not only enhances the durability of the installation but also contributes to the overall safety of the fuel system by minimizing the risk of damage. The consideration of these factors is crucial in proper fuel line routing for reliable aircraft operation.