Patent GB-568622-A (GB)
Title: Improvements in or relating to electrical signalling systems
IPC: B64F1/00
Filed: 1943-10-09
Abstract: 568,622. Electric signalling systems. AUTOMATIC TELEPHONE & ELECTRIC CO., Ltd., and SIMPSON, L. M. Oct. 9, 1943, No. 16553. [Classes 40 (i) and 118 (ii)] [Also in Group XL] In a system for supervising the movement of aircraft on an aerodrome, the perimeter track is divided into sections such that the ends of the runways each adjoin a different section, and the junction points are equipped with detector pads of the kind used in road traffic-control systems for controlling indicating equipment at a control point and with illuminated stop signs which are operated from the control point. The indicating equipment comprises a large mimic diagram (not shown) which is illuminated under control of the pads to show the occupied and clear sections of the aerodrome, and a panel, Fig. 2, having lamps for indicating the progress of particular aircraft and keys for controlling the stop signs. Since several aircraft or vehicles may be in a section at the same time, circuit arrangements are provided for counting them in and out of the section. It is intended that traffic shall be one-way, and therefore the pads and stop signs will be operative at only one end of each section at any given time. The panel, Fig. 2, includes a small diagram on which the particular runway and perimeter sections to be used in landing and taking off are lighted under control of a multi-position switch, which is set according to the direction of the wind. The control officer assigns a horizontal row of lamps and keys for each aircraft landing or taking off, there being separate sections for aircraft of different types, and its position on the aerodrome is then shown by the lamps in that row in accordance with the legends at the top of the panel. The " permission to land " buttons in column 2 light the red lamps in the adjoining column and also light the stop signs of the perimeter sections at each end of the runway in use : these are extinguished when the landing aircraft has moved off the runway. A common cancel key serves to clear down the indications relating to aircraft that have entered the park. Aircraft about to take off are allowed to move first to the beginning of the perimeter section adjoining the runway and then on to the runway, buttons in columns 20, 21 being operated in succession. The latter buttons light the green lamps in column 3 and the appropriate stop signs. Buttons in column 22 serve to clear down a row of indications when the aircraft is airborne. A record of the general type of each aircraft landing together with its time of arrival is obtained by means of a row of photoelectric cells 11 sunk in a trough 12 in the runway and an adjacent row of lamps 15 beneath an infrared filter 16. During daylight a certain number of the cells are de-energized as an aircraft passes over the trough and a dotted-line indication of the wing-span is made on a clock-driven chart 19. During darkness the lamps 15 are switched on and the cells operate in the reverse manner, a certain number being energized by reflection from the under-surface of the wing.