What is the effect of altitude on fuel flow?

The effect of altitude on fuel flow in aircraft is influenced primarily by the decrease in air density as altitude increases. At higher altitudes, the air becomes thinner, meaning there are fewer air molecules in a given volume of air. This reduction in air density affects the engine's performance, particularly in terms of the air-fuel mixture that is being burned in the combustion chamber.

As altitude increases, fuel flow typically increases to compensate for the decrease in the amount of available air. The engine management system (especially in turbine engines) adjusts fuel flow to maintain the optimal fuel-to-air ratio for combustion, ensuring that the engine continues to operate efficiently despite the thinner air. This adjustment is vital for maintaining the power output of the engine, which can otherwise be compromised due to insufficient air.

In summary, as altitude increases and air density decreases, it is necessary for fuel flow to increase to ensure the engine receives an adequate amount of fuel in relation to the reduced air supply. This concept is crucial for pilots to understand, as it affects engine performance, fuel efficiency, and overall flight operations at different altitudes.