Wind shear

Wind shear from a microburst, as compared to wind shear resulting from a gust front, is particularly hazardous because it is a short-period event which creates very strong wind gusts with a large variation in direction over a very short distance (1/2 to 2 1/2 miles in diameter).

The first effect of a wind shear was detected at 34 to 42 seconds into the takeoff, at a speed of about 115 KIAS with the airplane about 3,800 feet down the runway. An average shear rate of about 2.5 knots per second resulted in an interruption in acceleration at this point with the airspeed remaining at 115 to 120 KIAS for 7 to 10 seconds.