I assume we are talking A320 family here
As above, my Big employer has an "SOP" for F3 on 320/321, FF on 319, in order to "save fuel". However, either Flap setting can be used on any model as crew see fit, and they also give a long list of factors that might affect that decision (e.g. EAI, tailwind, LDA).
My observations:[LIST=1][*]F3 saves about 7Kgs an approach - assuming the F3 to FF is selected just prior 1000' for "stabilised approach criteria"
[*]A321 and A319 F3/FF Vapp is ~10K different, and attitude little changed[*]A320 only adds about 3K, and has much higher nose attitude, confirmed by "high nose attitude on Landing events" being a problem on, almost exclusively, F3 A320 approaches[*]On the A321 this can result in a comparatively high approach speed, which some circumstances might dictate best avoided[*]On the A319 the extra 10K can be very useful to get a decent approach speed / make an exit[*]My RHS colleagues do have a good line in excuses not to use F3 - which I can only assume reflects what most LHS do...