GB1117741A - Improvements in or relating to apparatus for displaying flight instrument information in aircraft - Google Patents

Abstract

1,117,741. Aircraft instruments. SPECTO AVIONICS Ltd., and MINISTER OF TECHNOLOGY. 28 Oct., 1965 [4 Sept., 1964], No. 36440/64. Heading B7W. In a " head-down " flight display system on an aircraft one or more cathode ray tubes provide a display in the form of at least one digital sub-display comprising alphanumeric characters which are changeable as a function of a flight variable and at least one analogue display simulating a function of another flight variable. In the arrangement of Fig. 1, the display is formed on two tubes. The right hand one gives a representation 10 of absolute altitude which consists of a fixed symbol 12 and a mobile horizon line 11 which when rotated relative to symbol 12 indicates the degree of bank. Line 11 is associated with mobile dotted horizon lines 13 marked at 10-degree intervals up to Œ180 degrees to indicate in association with symbol 12 the elevation angle of the aircraft. A height indicator 20 comprises a digital read-out derived from barometric, radio or radar instruments, the height measurements being sampled at intervals of, e.g. half-a-second to avoid blurring of the numerals. A similar digital read-out 41 denotes air speed and an associated read-out 42 denotes air speed error, a symbol 44, when aligned with a central dot 43 indicating that the aircraft is flying at a selected airspeed, displacement of symbol 44 indicating deviation from the selected air speed. A row of dots 32 represent vertical speed, the indicator being an extensible line 31 which when above the dots represents climb and when below, descent. Heading or track is denoted by read-out 50, in which the last digit is small to avoid confusion with air-speed numerals 41. An indication of side slip is provided by a mobile marker 62 movable laterally within a rectangle 61. A director display on the other tube comprises symbols 72 and 71, similar to the symbols 12 and 11, to represent the attitude of the aircraft in bank and elevation. Three bars 73, symbolizing an imaginary triangle with its apex on index 72 gives an indication, by distortion, of the errors in azimuth and elevation. In Fig. 2 (not shown) the vertical speed indicator is arranged as a semicircle of dots (33), an arcuate extensible marker (34) extending either upwardly or downwardly over the dots. Also arrows (21) supplement the height indicator (20) to indicate climb or descent. The airspeed indicator (40) reads in terms of Mach No. instead of airspeed and different forms of heading (50) and slip (60) are provided. In the embodiment of Fig. 3 (not shown) the director display includes an indication (80) of unexpired range.