Originally Posted by
sycamore
DH106,the reason that older,straight-wing a/c had a `nose-down ` attitude on approach is that at slower approach speeds ,the flaps are extended,Fowler flaps which move back and down,effectively increasing wing area,This has the effect of moving the aerodynamic `Centre of Pressure`(total LIFT) back,resulting in a `nose down trim..
Modern jets are the same,except that swept wing aircraft also have `leading-edge` flaps/slats/slots,which offset the CoP`s aft movement,and change the approach attitude to more `nose-up`..
Well, it's true what you say about the CoP moving with high lift device deployment - but any changes in the centre of pressure would be trimmed out to give an angle of attack that suits the approach airspeed in the current lift configuration of the wing. Changes in the position of the centre of pressure don't directly dictate the approach angle of attack, only the amount of elevator trim required to achieve it.