What does the term "VASI" stand for?

The term "VASI" stands for "Visual Approach Slope Indicator." This system is designed to provide visual guidance to pilots during the approach to landing, indicating whether they are on the correct glide slope towards the runway.

A VASI system typically consists of a set of lights that change color based on the aircraft's position relative to the optimal approach path. When positioned correctly on the glide slope, pilots will observe a specific color combination of lights, which helps assure them that they are safely aligned for landing. This visual aid is crucial, especially in conditions of low visibility, allowing for safer and more accurate landings.

Understanding what VASI does and how it functions is important for pilots, as it directly relates to their ability to perform effective approaches and landings, ultimately ensuring flight safety.