ence and "intense up- and downdrafts" ("Service Area: Convective Hazards," n.d., p. 4-1).
Windshear is another weather phenomenon that can occur even in clear air. It is simply "rapidly changing wind currents," although there is a particular type of wind shear referred to as "microbursts" that produce exceptionally strong windshear ("Making the Skies Safe from Windshear," 1992). Microbursts, or downbursts, are "short-lived downdrafts that radiate outward as they rush toward the ground," creating "increasing headwind over the wings of an oncoming aircraft" with a resulting spike in airspeed that causes the plane to lift ("Making the Skies Safe from Windshear," 1992). The shear "quickly becomes a downdraft and then a tailwind" as the plane passes through it, reducing airspeed over the wings and eliminating the extra lift and speed, making the plane prone to sudden loss of airspeed and altitude ("M
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