An Approach Lighting System (ALS) is a series of lights located near the runway that helps pilots during the landing phase of flight. These lights provide visual guidance, indicating the correct approach path and helping to improve visibility in low-light or poor weather conditions. The system typically includes a combination of steady and flashing lights, which can vary in configuration depending on the airport's requirements. The ALS is crucial for enhancing safety during landings, especially at airports with limited visibility. It works in conjunction with other systems, such as the Instrument Landing System (ILS) and Runway Visual Range (RVR), to ensure that pilots can accurately align their aircraft with the runway.