A flight management system is provided for generating a variable thrust cutback during aircraft departure. The flight management system includes memory storing a sound exposure level limit for a navigation flight and storing expected sound exposure levels for an aircraft, and one or more inputs for receiving sensed aircraft variables including altitude and airspeed. The system also includes a processor for processing the sensed altitude and airspeed and stored sound exposure levels. The processor further computes an engine thrust value that complies with the sound exposure level limit based on the altitude, airspeed and the sound exposure levels for controlling aircraft throttle during departure.