34 WIND Figure 8-17.  Crosswind approach and landing. of rudder or nose-wheel steering, while keeping the upwind  wing from rising by the use of aileron. When an airplane  is airborne, it moves with the air mass in which it is flying  regardless of the airplane’s heading and speed. When an  airplane is on the ground, it is unable to move with the air  mass (crosswind) because of the resistance created by ground  friction on the wheels.  accomplish this results in severe side loads being imposed  on the landing gear. If the wing-low method is used, the crosswind correction  (aileron into the wind and opposite rudder) is maintained  throughout the round out, and the touchdown made on the  upwind main wheel. During gusty or high wind conditions,  prompt adjustments must be made in the crosswind correction  to assure that the airplane does not drift as the airplane  touches down. As the forward momentum decreases after  initial contact, the weight of the airplane causes the downwind  main wheel to gradually settle onto the runway. Characteristically, an airplane has a greater profile or side  area behind the main landing gear than forward of the gear.  With the main wheels acting as a pivot point and the greater  surface area exposed to the crosswind behind that pivot point,  the airplane tends to turn or weathervane into the wind. In those airplanes having nose-wheel steering interconnected  with the rudder, the nose wheel is not aligned with the runway  as the wheels touch down because opposite rudder is being  held in the crosswind correction. To prevent swerving in  the direction the nose wheel is offset, the corrective rudder  pressure must be promptly relaxed just as the nose wheel  touches down. Wind acting on an airplane during crosswind landings is the  result of two factors. One is the natural wind, which acts  in the direction the air mass is traveling, while the other  is induced by the forward movement of the airplane and  acts parallel to the direction of movement. Consequently,  a crosswind has a headwind component acting along the  airplane’s ground track and a crosswind component acting  90° to its track. The resultant or relative wind is somewhere  between the two components. As the airplane’s forward  speed decreases during the after landing roll, the headwind  Particularly during the after-landing roll, special attention  must be given to maintaining directional control by the use  Crosswind After-Landing Roll 8-16