Patent GB-1327771-A (GB)
Title: Aircraft take-off and landing monitor displays and apparatus
IPC: B64D45/00
Filed: 1970-12-29
Abstract: 1327771 Aircraft indicators F G MILES ENG Ltd 29 Dec 1970 [27 Sept 1969] 47658/69 Heading B7W An aircraft apparatus used when landing and taking off includes a display instrument 10 comprising two lengths of tape 11, 12 alongside one another, respectively bearing an index 22, 23 and respectively having driving means 13, 14, Fig. 3, whereby the indices on the tapes move independently along two scales, one scale 20 being calibrated in distance, the other 21 in speed of the aircraft. The boundary between a coloured portion 17, 171 and a white portion 18, 18<SP>1</SP> of each tape 11, 12 forms an index. Each driving means comprises an electric motor connected to one roller of a pair of rollers (not shown) round which a tape is wound. A mask 29, Fig. 1, adjustable by a knob 28 may be provided to extend from a distance corresponding to the length of the runway to the right of the instrument and an azimuth guidance display 32 may also be provided. The instrument forms part of a take-off and landing monitoring apparatus, Fig. 3. For take-off, a pointer 24, slidable along the scale 20, is set by a knob 25 to correspond to a critical distance along the runway, by which the aircraft must take off, and the right hand index of a similarly slidable group 30 of three illuminated indices fixed relative to each other is set by a knob 31 at a corresponding critical speed on the scale 21. A switch 26 is also set to TO (take off), which causes a mode switch 42, Fig. 3, to connect an airspeed signal source 16 to the speed tape drive motor 14 and to disconnect a source of groundspeed signals derived from a distance signal source 15 via a differential amplifier 41. Change-over of the switch 26 operates an indicator 27 indicating "AIR" or "GROUND" speed and effects reversal of the drives to the rollers of the tapes 11, 12, and adapts knob 25 to move the distance tape 11. The pointer setting sets three distance counters of a numerals store (101), Fig. 46 (not shown) in a comparator 50, Fig. 3, which provide three signals to the group 30 corresponding to the critical distance and two distances below it, but only if the critical airspeed and airspeeds corresponding with the smaller distances are reached within these distances. The signals switch off an amber (NO-GO) light in each index of the group 30 and switch on a green (GO) light. For landing, the switch 26 is moved to "L" and causes the mode switch 42 to connect the airspeed source as the aircraft approaches, but switches to the groundspeed source on landing via a microswitch in the undercarriage. Also the coloured part 17 of the distance tape 11 is positioned on the left so as to move in a direction opposite to that during take off, the driving means only being responsive to distance signals once the aircraft has passed a certain point on the landing run. The lights of the group 30 may function to warn the pilot of distances travelled along the runway during landing or may be switched off by the mode switch 42. The comparator circuit, Fig. 46 (not shown) is described in detail in the Specification, and may provide signals to an acceleration director 50, Fig. 3. Acceleration is indicated by indicator 60 which receives speed signals via a differential amplifier 62.