This
system accompanies the alarms of TAWS type and in particular the alarms of “Avoid
terrain” type indicating to the
pilot that he has passed the limit point of success of a standard vertical avoidance maneuver, indications (32, 33) of free-travel distances in
azimuth sectors suited to a clearance maneuver and one or more recommended relief avoidance maneuvers (A, B), both lateral and vertical. For the determination of the limit point, it monitors the penetration of a model of the
terrain being flown over into a first protection volume (1) linked to the aircraft and configured in such a way as to model a standard vertical avoidance maneuver trajectory executed without notable
delay. For the determination of the
azimuth sectors open to a clearance maneuver, it analyzes the penetrations of the model of
terrain being flown over in a second protection volume with large
azimuth aperture, linked to the aircraft and configured in such a way as to contain the limit point protection volume (1). To evaluate the free-travel distances, it searches for limit points of effectiveness of a standard vertical avoidance maneuver, on arbitrary distancing trajectories in the azimuth sectors open to the clearance maneuvers. Based on the determination of these free-travel distances, the
system determines the limit instant of manual
initiation by the
pilot or automatic
initiation of an avoidance trajectory and determines the
optimum route alteration to be initiated prior to the avoidance maneuver.