Development of 4-D Time-Controlled Guidance Laws using Singular Perturbation Methodology

Aircraft flying conventional descents and approaches into high density terminal areas often waste fuel. Such is also the case whenever they are delayed while awaiting approach clearance. Simulation results have shown that in heavy traffic, time-controlled (4-D) guidance in the aircraft will be necessary to realize the full potential of fuel conservative procedures. This paper focuses on the analysis of the 4-D guidance problem in the longitudinal plane. Singular Perturbation Theory is applied to reduce the computational burden of solving the resulting optimal control problem.