In a previous series of papers (Refs. 1-3), wedeveloped a trajectory optimization algorithm andincorporated it into the NASA Ames ACSYNT aircraftdesign synthesis code.4 The algorithm determines near-optimal fixed-range trajectories of supersonictransports. The method is based on singularperturbation theory. A parameter is inserted in theequations of motion in such a way that the equations aredecoupled into three time scales. Each of the three sets of equations is solved by expanding all state and controlvariables to first order, that is by retaining the first twoterms in the asymptotic expansions. The solutions arethen matched to give uniformly valid approximations tothe original equations of motion. The details of theapproach are given in Refs. 5 and 6.