What is the impact of cold temperature on the viscosity of jet fuel?

When temperatures drop, the viscosity of jet fuel increases. Viscosity is a measure of a fluid's resistance to flow, and as the fuel becomes colder, its molecular structure undergoes changes that result in thicker, more viscous fluid characteristics. This increased viscosity can affect the fuel's ability to flow through the fuel system, potentially leading to challenges such as fuel starvation or reduced pump efficiency.

Cold temperature can lead to gel-like behaviors in certain types of jet fuels, primarily those containing paraffins, which solidify more readily compared to other fuels at lower temperatures. The thicker fuel makes it harder for fuel pumps to draw and transfer it, impacting engine performance during takeoff and at altitude, particularly in colder climates.

Recognizing this increase in viscosity is critical for aviation maintenance and operations, as it informs the selection of fuel types suitable for specific temperatures and the need for fuel system heating mechanisms to ensure optimal performance in cold environments.