GB922965A - Improvements in or relating to visual position-indicating arrangements - Google Patents

Abstract

922,965. Aircraft beacon lights. GENERAL ELECTRIC CO. Ltd. Sept. 29, 1961 [Oct. 28, 1960], No. 37151/60. Class 75 (4). [Also in Group XXXVIII] In a lamp arrangement for providing an observer approaching a location with an indication of his position relative to an approach plane passing through the location, particularly for guiding aircraft in to land, the colour of the light the observer sees changes as he crosses the plane. In Fig. 1 each half of the beam of light from a lamp 1 on either side of a plane 3 is filtered by axially spaced red filters 4, 5. As the observer goes from A-B he sees only red light, from B-C red and white light until at C he sees white light only, the light remaining white from C-D in spite of filter 4 as the intensity of white light is much greater than that of the red. Opaque screens 6, 7 cut off the upper and lower edges of the light beam. The apparatus of Fig. 2 (not shown) comprises a rectangular casing with two red filters placed at opposite ends. In Fig. 3, casing 10 houses opaque louvres 17, a light-spreading glass plate 16 and red filters 20, 19.