Optimum cruise profiles in the presence of winds

The author presents methods for computing an acceptable optimum cruise profile with step climb points that are acceptably separated when wind and temperature variations with altitude are taken into account. Four methods for filtering out spikes and stutters are described. One of them has been selected to provide an acceptable profile with minimum increase in flight cost. It involves first identifying candidate step climb points and then for each such point doing trial predictions for 500 nmi at each legal altitude at and above the current altitude, but not above a computed maximum altitude. Since displaying the true optimum altitude to the pilot may be misleading, methods for computing recommended cruise level are studied and one method is selected. Plots of simulation runs based on the Boeing 747-400 with a Honeywell flight management system are presented to illustrate and compare methods. Since maximum altitude is used in the methods described, maximum altitude computation is described