Method of indicating the lateral manoeuvre margins on either side of the flight plan path of an aircraft

A method for signaling the lateral margins of maneuver that exist on either side of a trajectory scheduled in a flight plan of an aircraft furnished with a locating device and having access to a terrain elevation database, comprising the steps of:

• displaying, on a navigation screen, with the vertical navigation profile giving the largest terrain elevations catalogued in the terrain elevation database, encountered on the trajectory scheduled in the flight plan, along a navigation band whose width takes account of the uncertainties of location of the aircraft, of the inaccuracy of the terrain elevation database and of the lateral tolerance allowed in the tracking of the trajectory scheduled in the flight plan, a vertical profile of lateral margins of maneuver giving the largest terrain elevations catalogued in the terrain elevation database, encountered on the trajectory scheduled in the flight plan, along a widened navigation band including the navigation band itself, supplemented with right and left lateral margins, wherein
• the lateral dimensions of the margins of maneuver are dependent on the imposed turning radius and the positions, with respect to the aircraft, of the points of ground traces of the turns with the imposed radius corresponding, for the aircraft, to a vanishing of its speed component perpendicular to the course scheduled in the flight plan,
• the lateral dimensions of the margins of maneuver are taken to the equal, for one, the right one Wr, to the largest value out of:
• the turning diameter 2R whose value is given by:
• R
• =
• TAS
• 2
• g
• ·
• tan
• ⁢
• ⁢
• φ
• roll
• TAS being the amplitude of the air speed of the aircraft, φroll being the angle of roll of the aircraft during the turning maneuver, and
• the values taken by the component xt perpendicular to the course scheduled in the flight plan on the ground trace of the turn with imposed radius, at the times tWr1 and tWr2 of the first and second vanishings of the aircraft's speed component perpendicular to the course scheduled in the flight plan,
• Wr=Max[2R;xt(tWr1);xt(tWr2)], and
• for the other, the left one Wl, to the largest of the values out of:
• the turning diameter 2R, and
• the opposites of the values taken by the component xt perpendicular to the course scheduled in the flight plan on the ground trace of the turn with imposed radius, at the times tWl1 and tWl2 of the first and second vanishings of the aircraft's speed component perpendicular to the course scheduled in the flight plan
• Wl=Max[2R;−xt(tWl1);−xt(tWl2)].