Originally Posted by
NutLoose
It’s not really the weight of the aircraft but it’s footprint.
Actually, you're both sort of right, it's the weight of the aircraft and the surface area that weight is distributed over; when calculating the ACN, the main elements are number of wheels (undercarridge layout), size and pressure of tyre (how much surface area of the tyre is in contact with the ground), and flexability of the pavement you're going to be trampling over. Obviously, as the weight of the aircraft goes up so does the ACN.