I have a question regarding fuel flow and drag computations that appear on the FMC of most aircraft.
I've learned that FF deteriorates as an aircraft gets older due to engine performance, condition of the skin etc. But what is the usual DRAG/FF specifications for a brand new, “out of the box” airplane? Is it usual to have a 1-2% higher FF than the plane was designed for? Is there any sort of compensation that airlines get when Boeing or Airbus delivers a plane with a 1.0 or 2.0 % FF?
Is having an increased Drag performance less common than an increased FF rate?