【正文】
Using data of Mohawk. l For a ramp gust, 。 hence, l This value of u(t) putes the inertial flight speed of the aircraft. But we are also interested in the change in relative air speed. ? Change in relative air speed: . ? At steady state: . l Observations: ? For a tail wind shear (順風(fēng)), , the inertial flight speed is increasing, but the relative air speed is decreasing. Eventually, the relative air speed will decrease by an amount . ? Decrease in relative air speed reduces lift, causing the A/C to loss altitude. ? May cause crashes at take off or landing, see discussion below. (B) Change in altitude in a wind shear: l Rate of change in altitude: . l A is assumed。 hence, . l Therefore, and l Using data of Mohawk as an example: l Observations: ? Eventually, , indicating a A/C crash, for . ? This danger of crash may occur near an airport where an aircraft is in low altitude doing take off or landing.112