What is the function of the Approach Lighting System (ALS)?

The function of the Approach Lighting System (ALS) is crucial in aiding pilots as they transition from instrument flight to visual flight during the landing process. As aircraft approach an airport, the ALS provides a series of lights that visually guide pilots toward the runway, particularly in low-visibility conditions. This system typically consists of a variety of lighting configurations that help delineate the runway environment, making it easier to identify the runway and align for landing.

This transition from instrument to visual flight is particularly important because it helps ensure safety during the final approach phase. When visibility is marginal, having a clear visual reference allows pilots to safely gauge their altitude, approach angle, and overall positioning concerning the runway. Thus, the ALS plays a vital role in facilitating this transition and enhancing situational awareness for pilots as they prepare for landing, especially in challenging weather conditions.