Approach Lighting System (ALS) explained simply Ever wondered how pilots manage to line up with the runway during low visibility or at night? That’s where the ALS comes in. It’s a sequence of high-intensity lights leading up to the runway threshold. It helps you visually identify where to land, and gives critical guidance to align the aircraft, especially in low visibility or night operations. You’ll find different ALS configurations depending on the type of approach: • Non-instrument • Non-prec