What kind of information does a runway VASI system provide?

A runway VASI (Visual Approach Slope Indicator) system is designed to provide pilots with visual cues regarding their approach and descent profile as they land. Specifically, it indicates whether the aircraft is on the correct glide slope for landing by illuminating lights in specific patterns.

When the lights show a particular configuration, they inform the pilot whether they are too high, too low, or on the proper descent path to the runway. This is crucial as it helps ensure a safe and effective landing approach, enhancing both situational awareness and safety during the landing phase.

Understanding this function is vital for pilots, as it assists in making necessary adjustments to maintain the appropriate glide slope for landing safely. Other options, such as providing weather conditions, aircraft altitude, or distance to landing, involve different systems or instruments and are not the primary purpose of the VASI system.