Optimization of Flexible Approach Trajectories Using a Genetic Algorithm

Abstract

Current air traffic management in the terminal area is based on published sets of standard routes. However, a new procedure called the continuous descent approach has been recently proposed to decrease noise disturbances. To allow increased use of continuous descents and simultaneously increase performance in terms of other important aspects such as throughput, it may be beneficial to replace the predetermined fixed approach trajectories with more flexible trajectories instead. This is studied through optimizing approach trajectories, for which a genetic algorithm is used. Analyses show that allowing more flexibility in the approach routes can increase throughput, enable scheduling trajectories closer to continuous descent approaches, and result in routing flights less often over residential areas. However, it is also shown that flexible approach trajectories may increase airspace complexity, which in effect may make the task of air traffic control more complicated. Nomenclature a = longitudinal acceleration, dVC/dt CR H = mean maximum horizontal closure rate CR V = mean maximum vertical closure rate d = time deviation ˆ E = energy rate demand F = objective function value f = fitness h = altitude L = noise load on community; length M = number of segments N = number of flights N8 = maximum number of aircraft pairs with less than 8-n mi (14.82 km) horizontal distance N13 = maximum number of aircraft pairs with less than 13-n mi (24.08 km) horizontal distance Nac = maximum number of aircraft with an altitude change rate over 500 ft/min (2.54 m/s) NC = number of crossings points between arrival and departure flows Npk = peak number of aircraft simultaneously in the terminal area Nsc = maximum number of aircraft with an airspeed change greater than 10 kn (5.14 m/s) during a 2-min interval R = radius SH = mean minimum horizontal separation distance SV = mean minimum vertical separation distance T = segment type; throughput VC = calibrated airspeed Vg = ground speed γ = flight-path angle