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3. Types of Turbulence
Turbulence is divided into four general types based on the meteorological and
physical properties responsible for its existence. These types are convective, mechanical,
wind shear, and high altitude clear air turbulence (CAT). Although the principal cause of clear
air turbulence is wind shear, it is given a special classification because of its importance for
jet aircraft.
4. Convective Turbulence
a. As discussed in Weather Causes, convection results from uneven heating of the
earth's surface causing currents of variable strength. The following illustrations show how a
normal descent may be affected by nearby changes in the type of surface.
Downward currents allow the aircraft to fall below the normal descent path causing it to enter
the landing area short of the intended point.
Figure 2
