Cost Efficiency of an Aircraft Arrival Speed Profile

CI= Cost Index D = drag D = effective drag per unit mass F = total fuel consumption J = direct operating cost Jnominal = direct operating cost of flying a nominal speed profile Joptimal = direct operating cost of flying a cost-optimal speed profile ∆J = cost efficiency, Jnominal − Joptimal ∆J (%) = ∆J as a percentage of Jnominal L = aircraft’s lift P = aircraft state as a function of path distance coordinate and true airspeed P f = final aircraft state P i = initial aircraft state R = effective cost per unit distance per unit mass T = thrust Tmax = maximum thrust V = true airspeed V̇ = true airspeed change rate V f = final true airspeed V i = initial true airspeed Vmc = minimum-cost speed W = aircraft’s weight