www.faaflighttraining.com presents Airspeeds
CAS: Calibrated Airspeed = Indicated airspeed corrected for installation and instrument errors. CAS equals TAS at standard atmospheric conditions (ISA) at MSL Mean Sea Level.
GS: Ground Speed. Speed of the airplane relative to the ground.
IAS: Indicated Airspeed as shown on an airspeed indicator.
KCAS: CAS indicated in Knots.
KIAS IAS indicated in Knots.
TAS: True Airspeed. The speed of the airplane relative to the air.
TAS is CAS corrected for errors due to altitude and temperature.
VA: Maneuvering Speed. Maximum speed at which the airplane is not overstressed at full deflection of control surfaces. Full or abrupt control surface movement is not permissible above this speed.
VFE: Maximum flaps extended speed. This speed must not be exceeded in any operation.
VNO: Maximum structural operating speed. This speed may be exceeded only in smooth air, and with caution.
VR: Rotation speed or takeoff speed.
VREF: Reference Speed
VS: The power-off stall speed with the airplane in its standard configuration.
VSO: The power-off stall speed with the airplane in landing configuration.
VX: Best Angle of climb speed.
VY: Bets rate of climb speed.