US Patent 7558652 On-board system for constructing an aircraft track

A system (20) on board or suitable for use on board an aircraft to define an aircraft track having a plurality of segments, the system includes a display unit (10) arranged to display an image (11) containing a representation of the footprint of a segment (S, S1, S2) in a plane or level; an analog input member (17) for inputting altitude data (A) into a computer (13) connected to the display unit; and a calculation program or module arranged to determine a representation (C1, C2, PR1, PR2) of relief that is dangerous for a flight altitude equal to the value of the altitude data (A), and to superimpose (or include) the representation on (in) the image (11).