What does ALS stand for in aviation?

In aviation, ALS stands for Approach Lighting System. This system is crucial for landing operations, particularly in low visibility conditions. The Approach Lighting System consists of a series of lights arranged in a specific configuration to help pilots transition from instrument flight to visual flight. These lights provide important visual cues for pilots as they approach the runway, aiding in horizontal and vertical guidance during the final approach segment.

The specific layout of lights can vary based on the runway's design and the approach category, but the primary purpose remains consistent: to enhance the pilot's ability to see the runway in the final stages of landing. The use of ALS is part of the operational standards to improve safety during the critical landing phase, especially when weather conditions might obstruct visibility.