Using speed brakes on a320.
I like to point out that I am just getting started out on the a320, and just looking for some insight on usage of speed breaks.
I read somewhere that they should not be used in managed descent, but only in open descent?
Not sure if this is true, but i would like to understand why, if it is.
And lastly, any other times I shouldn't use them? I read they should be used only up till flap 3, correct?
Also(silly ques), does the same concept of using them apply to the 319, 321 as well?
Thanks n advance!