Its all about the minimum energy level that an aircraft should have at touch down and this is based on the ground speed that the aircraft will have at Vapp with the expected wind.
lets suppose.
Conventional Aircraft (Head wind 20 kts N1 55% Speed target 130 kts )
AIRBUS (Head wind 20 kts N1 55% IAS target 130 kts )
then the GUST......
On the conventional (Head wind increses to 50kts ,Speed trend is going up
And Thrust will go to idle as Speed target will remain at 130KTS)
On the AIRBUS (Head wind increases to 50 kts ,IAS Target and speed increases to lets say 160Kts Speed trend is going up And Thrust will be increased)
then the SHEAR (From head to calm)........
On the conventional (Head wind decreases to zero Speed trend is going down and bellow the 130 kts target And thrust wich was near idle is know having problems to recover)
On the AIRBUS (Head wind decreases to zero Speed trend is going down from 160 kts to the original 130 kts And thust wich was initially high is reducing with no problems.)
SO.
CONVENTIONAL AIRCRAFT (BOEING) THE ENERGY IS LOW AND CLOSE TO THE GROUND (DANGER), THRUST HAVE TO BE SIGNIFICANTLY INCREASED.
AIRBUS, THE ENERGY IS HIGH, THRUST IS SMOOTHLY REDUCED.
luis
