GB1252587A - - Google Patents

Abstract

1,252,587. Aircraft instruments. V. WILCKENS. 4 Nov., 1968, No. 52099/68. Heading B7W. A pictorial situation display system for controlling the attitude and desired path of an aircraft comprises a display screen from which bank angle, pitch angle, lateral and vertical deviation from the desired path are quantitatively estimatable, the pictorial representation of the desired path being a rectangular channel formed by a bottom plane having a centre line, and two vertical side-wall planes are erected on each edge of the bottom plane and each having a longitudinal line in a predetermined relation to the bottom plane, the line formed by the intersection of a conceptual vertical plane through the centre line of the bottom plane and a conceptual plane through the said lines of the side wall planes locating the desired path relative to a pilot's eyes. The planes are formed by dots or lines computed by external sensors on the ground and set up on a cathode ray tube screen in the aeroplane. In landing the channel is seen to bend upwards into the approach sector so that the longitudinal lines on the side-wall planes coincide with a predetermined glide slope. The height of the lines above the runway at touch down being the actual height of the pilot's eyes at touch down. At that moment the perspective angle of the upper edges of the side-wall planes stretches to 180 degrees (see Figs. 2a-2d). In an alternative embodiment the pictorial representation constitutes an aircraft symbol of an imaginary preceding aircraft (see Fig. 8), which symbol is formed of a rudimentary fuselage and wing section and inverted T-shape tailplane section. These sections move relative to each other on the display screen corresponding to the position and attitude of the flying real aircraft in relation to the desired path. At zero deviation the tailplane section fits within the fuselage section with small gaps between its ends and the fuselage, the wings of fuselage section then being horizontal and in line with the cross-piece of the tailplane section. If desired the aircraft symbol and channel symbols may be used in combination. In a landing the displayed symbol represents the real aircraft moving on a conceptual rail-like path which extends to the intersection of the glide slope and runway at which point it becomes horizontal. This point is indicated by the tailplane section dropping relative to the other section. Preferably the ideal flight path is represented on the screen by a reticule. Particularly the desired flight path is represented by a vertical line and the ground at destination by a horizontal line. A plan view of the aircraft symbol may be shown below the horizontal line to indicate lateral and longitudinal displacement from the desired flight path. Equations are given for computing the bank angle for ideal interception. Speed may be indicated by a colour code.