Indicated airspeed (IAS)

Indicated airspeed (IAS) refers to the airspeed displayed on an aircraft’s airspeed indicator, which is not adjusted for errors caused by instrument, position, or other factors. This measurement reflects the speed of the aircraft as sensed by its pitot-static airspeed indicator, which is calibrated to account for the adiabatic compressible flow of standard atmosphere at sea level. IAS is not corrected for errors introduced by the airspeed system, such as instrument errors, position errors caused by incorrect pressure at the static port, and installation errors. Calibrated airspeed (CAS) represents IAS corrected for these types of errors.