In order to reduce fuel savings in a given flight the vertical navigation profile in terms of speed and altitude that provides the most economical flight has to be found. An algorithm was developed using an aircraft performance database to determine the optimal vertical flight profile considering a take-off weight, flight distance, step climb and weather conditions. This algorithm is based on linear interpolations of the performance tables using the Lagrange method. The algorithm according to departure date and coordinates, download the latest available forecast from environment Canada website and calculate the optimal taking into account the effects of wind, pressure and temperature. NomenclatureCI = Cost index FL = Flight level FMS = Flight Management System GARDN = Green Aviation Research & Development Network ISA = International Standard Atmosphere KIAS = Knots Indicated Airspeed LARCASE = Laboratory Research Laboratory in Active Controls, Avionics Controls, Avionics and Aeroservoelasticity. NFZ = No fly zones PDB = Performance database TOC = Top of climb TOD = Top of descent UTC Coordinated Universal Time VNAV = Vertical navigation