Why do we beep up the Nr to 103% before takeoff / landing in CatA profiles?
As I understand, we are on the wrong side of the L/D ratio, so inc in Nr actually increases the Drag (therefore torque / power reqmt) more than the Lift. So what is the benefit? Is it just more reserve of Nr in case of an OEI?
That's what I was taught: 103%Nr gives you a reserve to allow for droop when recognising and responding to an engine failure. Much the same as A109E/S with the 102%Nr selection, for the same reason.