What is the ideal scenario to achieve the best specific fuel consumption (SFC)?

The ideal scenario to achieve the best specific fuel consumption (SFC) is during cruise. This phase of flight is characterized by a consistent and efficient engine operation at optimal altitude and speed, where aerodynamic drag is minimized, and the engines can operate at their best efficiency levels.

During cruise, the aircraft typically travels at a steady speed and altitude, allowing the engines to maintain a consistent output with lower fuel consumption relative to the thrust produced. This is crucial for maximizing the distance the aircraft can travel on a given amount of fuel, making cruise the most efficient phase for fuel consumption.

In contrast, during climb, the aircraft requires more power to overcome gravity, leading to higher fuel consumption rates. During descent, the engines often operate in a reduced power state or may be throttled back, but the descent phase does not maintain the efficiency of cruise. Takeoff demands significant thrust to lift the aircraft into the air, resulting in even higher fuel consumption. Hence, the cruise phase stands out as the optimal time for minimizing specific fuel consumption.