A method is provided for managing the revising of a flight plan of an aircraft implemented by at least two systems, one being of avionics type (qualified, certified) and the other not. From a flight plan, flight plan revisions are determined, even assessed, then one or more of these revisions are selected and/or combined. Subsequently, these combinations are processed by the avionics system and the corresponding avionics parameters are calculated. By comparing the different results of avionics quality, the impact of each revision can be quantified then rendered to the pilot to assist in his or her decision-making, in particular with regard to negotiating the revisions with air traffic control. Combinatorial optimization and learning steps are described, as are system and software aspects.