Aircraft lighting

Aircraft lighting consists of: landing lights, position lights (wing and tail), formation lights, cabin lights (dome and worktable), indicator lamps, bomb-release signal light, interaircraft control-lamp assemblies, and instrument light. Landing Lights. The first landing lights on aircraft were attached to the lower surface of the airfoil or to the fuselage. These lamp assemblies used 240- or 420-watt 12-volt lamps, depending on the size and type of airplane. Later, to reduce the aerodynamic drag, the lamp assemblies were built into a mount, which was fastened to the leading edge of the wing. The next improvement was the insertion of the lamp assembly in the wings and the use of a curved cover glass to conform to the contour of the airfoil. Because of the increasing use of deicers and the use of the front surface of the wing to carry load, the leading-edge lamp assembly has been superseded by the present standard electric retractable-type landing-lamp assembly, which is mounted in the lower surface of the airfoil. Experimental tests are being conducted on sealed-beam lamps for aircraft landing lamps. The use of these lamps would permit increased wattage and light output and eliminate reflector maintenance. Position Lights (Wing and Tail). The Air Corps recently has standardized on the single-unit-type position light which will meet the requirements of the Civil Aeronautics Administration airline forward position lights and which will also meet the Air Corps formation flying requirements when used with a dimming resistor. The Civil Aeronautics Administration requirements for tail light is not met by the Air Corps because increased airplane performance can be accomplished by the use of a lamp assembly using a three-candlepower, T-3 1/4 miniature bayonet-base lamp.