PPRuNe Forums - View Single Post - Will you retract slats/flaps in windshear?
Old 27th Feb 2015, 17:09
  #41 (permalink)  
safetypee
 
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NOD, energy management might not be as simple as you imply (#40). Depending on the type of detection and guidance system, the form of energy management could be proportional to height above ground.
With relatively large ground clearance (according to aircraft, excess energy, etc) the guidance system is biased towards higher speeds to help transit the shear, whilst still climbing.
As height reduces, speed is traded for climb to maintain ground clearance; in some systems airspeed is traded such that at ‘ground contact’ airspeed=Vs.

An optimised guidance system should not exceed flap limit speeds, but could exceed retraction speeds. These aspects are not assured as many windshears can induce large and rapid speed reversals where the guidance / aircraft are incapable of reacting in such a short time.

In the previously linked incident (no guidance system), the crew were required to make rapid attitude changes – some significantly lower than expected, just to maintain their target airspeed (Vref). The focus of their attention was attitude and speed with little or no capability to consider anything else. The Captain was one of the most experienced on the aircraft type and in the operating environment.

Those who wish to discuss how to handle a shear immediately after take-off might consider why the conditions relating to shear were not identified before take-off.
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