Indicated Airspeed (IAS) is the speed displayed on the flight-deck instrument. This measurement is shown by an aneroid instrument that gauges the dynamic pressure of outside air entering a pitot tube. At sea level, under standard atmospheric pressure of 1013.2 mb and without wind interference, the IAS reflects the true speed of the aircraft over the ground. As the aircraft ascends, air density decreases, causing the indicated speed to be lower than the True Air Speed (TAS). However, when it comes to piloting the aircraft, the indicated airspeed is more crucial than the true airspeed. This is because the aircraft’s handling characteristics change with varying atmospheric density. Therefore, control speeds, such as V1 and V2, are expressed in KIAS, or Knots Indicated Airspeed.
