What is the function of the airspeed indicator during a flight?

The airspeed indicator plays a crucial role in flight by providing essential information about the aircraft's speed relative to the surrounding air. This speed is vital for various flight operations, such as determining stall speeds, maintaining proper flight dynamics, and ensuring safe maneuvering of the aircraft. Knowledge of airspeed allows pilots to make informed decisions regarding takeoff, landing, and cruising, as it influences the aircraft's performance characteristics.

Other options do not pertain to the primary function of the airspeed indicator. For instance, altitude is measured by an altimeter, fuel consumption is tracked using fuel flow indicators, and direction is indicated by a heading indicator or compass. Therefore, understanding the role of the airspeed indicator is integral to flight safety and efficiency.