Calculating Optimum Landing Weight

Performance charts for aircraft designed to operate on soft fields, such as the C-17A and C-130J, often present a table relating the maximum number of passes that aircraft can achieve as a function of the weight of the aircraft and the CBR of the field. These charts assume that there is no runway resurfacing during operations, which could drastically increase the total number of passes. It was found that these performance data could be fit with an equation of the form ${P^{\max }} = aCB{R^b}{e^{ - c{W_L}}},$(1) where${P^{\max }}$is the maximum number of passes and${W_L}$is the landing weight. The coefficients a,