What is indicated airspeed (IAS)?

Indicated airspeed (IAS) is the speed that is displayed on an aircraft's airspeed indicator, which is derived from the aircraft's pitot-static system. This measurement is uncorrected for any variations in altitude or temperature, meaning it strictly reflects the dynamic pressure of the airflow around the aircraft at the altitude it is flying.

The significance of IAS lies in its direct relation to how an aircraft performs in the air. Unlike calibrated airspeed or true airspeed, which factor in corrections for temperature and pressure altitude, indicated airspeed provides pilots with immediate feedback regarding the aerodynamic qualities of the aircraft, such as its stall speed and drag characteristics.

This understanding ensures that pilots can maintain safe operation within performance limits, especially when engaging in maneuvers or landing approaches.