Air Base Approach Light

An Air Base Approach Light system, or Approach Lighting System (ALS), provides pilots with visual guidance during the approach to a runway, especially in low visibility or at night. It consists of a series of lights and signals, including central line lights, crossbars, and flashing lights, that help pilots align their aircraft with the runway centerline and maintain the correct descent path. ALS transitions pilots from instrument flight to visual flight and is classified by its complexity and length, with different systems for precision and non-precision instrument runways, and is designed to comply with international (ICAO) and national standards.