during an approach what is the effect of a sudden decrease in headwind component on IAS and rate of descent?

a) IAS and rate of descent would both increase
b) IAS and rate of descent would both decrease
c) IAS would decrease and rate of descent would increase
d) IAS would increase and rate of descent would decrease

i know that the IAS would decrease,, but what would happen to the rate of descent? in the book it states that the climb rate and descent rate is not affected by wind.. the climb and descent rate would be unchanged.. neither of the answers contain this.. im confused..

Hi Red,
One way to think about this is to imagine the effect the airspeed is going to have on your lift. If you decrease the airspeed, you will decrease the lift being produced by the wings, the weight will no longer be supported by the lift and your rate of descent will increase. The answer is (c).
You are right, wind has no effect on your rate of descent but in the case of wind shear, you are not descending in a constant wind. You are moving from a body of air moving at one speed into another moving at another speed and during the first few moments of transition, you will indeed suffer effects on airspeed and lift production due to the temporary change in the relative wind. Eventually though, the forces acting on the aeroplane will re-stabilise and the aircraft will continue its descent at the same rate as before oblivious to the hiccup as it passed through the shear.
Cheers,
Rich

hey rich,
thanks for the help.. at last understood.. thank you very much.

cheers