Construction of an aircraft's VNAV flight envelope for in-FMS flight trajectory computation and optimization

Abstract

This paper presents the results of a new method used for constructing an aircraft’s vertical navigation profile (VNAV) envelope, applied on an aircraft performance model described by linear interpolation tables. The method was developed for use in Flight Management System (FMS) trajectory computations and optimization. The main objective was to speed-up the trajectory generation/update and to reduce the volume of repetitive computations, especially those associated with a trajectory optimization. It considers a free-flight scenario with a vertical profile composed of unrestricted climb, constant-speed level flight, climb-in-cruise (no descentin-cruise) and continuous descent segments, at specified climb, cruise and descent speed schedules and a specified value of the air temperature deviation. It uses the same set of aircraft performance data (PDBs) as the FMS platforms.