Indicated Airspeed(IAS) The airspeed is shown on the flight-deck instrument.
Calibrated Airspeed(CAS)
Calibrated airspeed (CAS) is indicated airspeed corrected for instrument errors and position error
**IAS corrected for instrument errors
Equivalent Airspeed(EAS):
Equivalent airspeed (EAS) is defined as the speed at sea level, under ISA conditions, that would produce the same incompressible dynamic pressure that is produced at the true airspeed and the altitude at which the vehicle is flying.
**CAS corrected for compressibility(Sea Level)
True Airspeed(TAS)
Calibrated Airspeed (CAS )corrected for altitude and non-standard temperature - the speed of the aircraft relative to the airmass in which it is flying.
**CAS corrected for altitude and non-standard temperature
Ground speed(GS)
Ground speed is the horizontal speed of an aircraft relative to the ground.
**TAS corrected for wind
