A method for assisting in the navigation of an aircraft comprises steps of calculating and displaying a linear deviation on a first linear section and an angular deviation on a second angular section. The method comprises a calculation step for converting an angular deviation into an equivalent linear deviation, and, conversely, converting a linear deviation into an equivalent angular deviation. The method comprises a step of graphic representation, called unified monitoring, intended for the crew, of a deviation of the aircraft, on a lateral deviation axis and a vertical deviation axis; each of the deviations, lateral and vertical, being able to be represented on a linear scale, an angular scale or a mixed scale.