Method and device for determining a takeoff trajectory that allows the maximization of the takeoff weight of an aircraft

The method involves generating initial data comprising lateral profile (TL1) of standard takeoff trajectory (T1) and data relating to environment of takeoff airport. An auxiliary takeoff trajectory (T2) and obstacles (OB) to-be-flown over for nominal takeoff conditions are determined based on initial data. The optimum takeoff trajectory is obtained by modifying auxiliary trajectory, based on takeoff conditions, and obstacles to-be-flown over for non-nominal takeoff conditions. The maximum takeoff weight of aircraft (AC) is calculated based on optimum trajectory. An independent claim is included for device for determining auxiliary takeoff trajectory of aircraft for maximizing takeoff weight of aircraft.