SYMBOLS, ABBREVIATIONS AND TERMINOLOGY 符号、缩写和术语
 

GENERAL AIRSPEED TERMINOLOGY 一般空速术语

CAS Calibrated Airspeed is the indicated airspeed of an airplane corrected for position and instrument error. Calibrated airspeed is equal to true airspeed in standard atmosphere at sea level.
GS Ground Speed is the speed of an airplane relative to the ground.
IAS Indicated Airspeed is the speed of an airplane as shown on the airspeed indicator. IAS values published in this handbook assume zero instrument error.
KCAS Calibrated Airspeed expressed in knots.
KIAS Indicated Airspeed expressed in knots.
M Mach Number is the ratio of true airspeed to the speed of sound.
TAS True Airspeed is the airspeed of an airplane relative to undisturbed air, which is the CAS corrected for altitude, temperature, and compressibility.
VA Maneuvering Speed is the maximum speed at which application of full available aerodynamic control will not overstress the airplane.
VF Design Flap Speed is the highest speed permissible at which wing flaps may be actuated.
VFE Maximum Flap Extended Speed is the highest speed permissible with wing flaps in a prescribed extended position.
VLE Maximum Landing Gear Extended Speed is the maximum speed at which an airplane can be safely flown with the landing gear extended.
VLO Maximum Landing Gear Operating Speed is the maximum speed at which the landing gear can be safely extended or retracted.
VMCA Air Minimum Control Speed is the minimum flight speed at which the airplane is directionally controllable as determined in accordance with Federal Aviation Regulations. The airplane certification conditions include one engine becoming inoperative with autofeather armed, a 5-degree bank towards the operative engine, take-off power on operative engine, landing gear up, flaps in the take-off position, and most rearward CG. For some conditions of weight and altitude, stall can be encountered at speeds above VMCA as established by the certification procedure described above, in which event stall speed must be regarded as the limit of effective directional control.