Sunday, November 18, 2007


Some important airspeed limitations are not marked on the face of the airspeed indicator, but are found on placards and in the AFM or POH. These airspeeds include:
  • Design maneuvering speed (VA)—This is the "rough air" speed and the maximum speed for abrupt maneuvers. If during flight, rough air or severe turbulence is encountered, reduce the airspeed to maneuvering speed or less to minimize stress on the airplane structure. It is important to consider weight when referencing this speed. For example, VA may be 100 knots when an airplane is heavily loaded, but only 90 knots when the load is light.
  • Landing gear operating speed (VLO)—The maximum speed for extending or retracting the landing gear if using an airplane equipped with retractable landing gear.
  • Landing gear extended speed (VLE)—The maximum speed at which an airplane can be safely flown with the landing gear extended.
  • Best angle-of-climb speed (VX)—The airspeed at which an airplane gains the greatest amount of altitude in a given distance. It is used during a short-field takeoff to clear an obstacle.
  • Best rate-of-climb speed (VY)—This airspeed provides the most altitude gain in a given period of time.
  • Minimum control speed (VMC)—This is the minimum flight speed at which a light, twin-engine airplane can be satisfactorily controlled when an engine suddenly becomes inoperative and the remaining engine is at takeoff power.
  • Best rate of climb with one engine inoperative (VYSE)—This airspeed provides the most altitude gain in a given period of time in a light, twin engine airplane following an engine failure.

Instrument Check—Prior to takeoff, the airspeed indicator should read zero. However, if there is a strong wind blowing directly into the pitot tube, the airspeed indicator may read higher than zero. When beginning the takeoff, make sure the airspeed is increasing at an appropriate rate.

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