Aeronautical ground lighting (AGL)
is provided on an aerodrome (a defined area on land designed to be used the arrival, departure and surface movement of aircraft) for the guidance of pilots operating aircraft both at night and in low visibility conditions. An AGL system typically consists of approach lighting
, supplementary approach lighting, precision approach path indicators (PAPI), runway lighting
, taxiway lighting
, aerodrome beacons. Approach lighting provides visual information runway alignment, height perception, roll guidance, and horizon references to assist the pilot in transitioning from instrument flight to visual flight for landing. A PAPI system provides approach slope guidance to assist the pilot of an aircraft in flying a stabilized approach. Runway lighting, which is provided with threshold lights, runway edge lights and runway end lights, is used at airports to define the edges and end of a runway during nighttime and low visibility conditions. Taxiway lighting systems, including taxiway centerline lights, RGLs, stop bars and clearance bars, provides visual guidance lighting to facilitate taxiing.