Voxpop,
While your comments regarding AFPS05 are "technically correct", you massively mispaint the situation.
On AFPS05 if you have done the correct number of years to qualify for an immediate pension, but leave before your 55 point, then you do get paid a monthly sum immediately. Yes you are correct that it is not a "pension" as such - it is called an Early Departure Payment (EDP) is a certain % of your final pension depending on how many years you have done. To a certain extent it looks like a pension, walks like a pension and squawks like a pension - it just wasn't allowed to be called one, by law I believe.
My brief description is still well short of describing the intricacies of AFPS05, but your implication that you get nothing on AFPS05 if you have qualified but leave before 55 is well short of the mark!