system of lights on the side of an airport runway threshold that provides visual descent guidance information during final approach, what generally located on the left-hand side of the runway approximately 300 meters beyond the landing threshold of the runway, lennuvälja maandumisraja kõrval paiknev pilootidele mõeldud visuaalne mõõte-/abivahend maandumise lihtsustamiseks, mis paikneb tavaliselt maandumisraja algusest umbes 300 meetri kaugusel