Patent ID: 7558652

Claim:
A system ( 20 ) enabling an operator to define or modify, in an interactive manner, an aircraft track comprising a plurality of segments, the system comprising: a display ( 10 ) arranged to display a footprint image ( 11 ) representing a footprint of at least one segment of plural successive segments (S, S 1 , S 2 ) that comprise an aircraft track on a horizontal plane, the footprint image comprising i) a first strip corresponding to a horizontal positioning error (EPH) and ii) an adjoining second strip corresponding to an avoidance margin (MC) such that a total width of the footprint image corresponds to a total comprising twice the horizontal positioning error (EPH) plus twice the avoidance margin (MC); a computer ( 13 ) connected to the display; an analog input member ( 17 ) enabling an operator, interactively during flight, to input altitude data (A) for a part of the aircraft track into the computer; and a calculation program stored in a computer readable medium arranged to determine a relief representation (C 1 , C 2 , PR 1 , PR 2 ) of at least one dangerous relief for a flight altitude equal to the input altitude data (A) and to superimpose said relief representation on the footprint image ( 11 ) displayed on the display, the relief representation of the at least one dangerous relief comprising i) a first zone defined by a first contour line (C 1 ) located at a first altitude equal to the input altitude data (A) minus a vertical positioning error (EPV) and ii) a second zone defined by a second contour line (C 2 ) surrounding the first zone, the second zone defined by the first altitude minus an avoidance margin (MC), wherein the operator, during flight, is enabled by use of the analog input member to interactively change the input altitude data (A) and the position and direction of the at least one segment to update the relief representation and the footprint image displayed on the display allowing operator to cause the first and second contour lines to be displayed larger and smaller and intersecting with the footprint image.