What is a PAPI?

• A. A radar-based instrument landing aid
• B. A light system usually found on the left beside a runway indicating the aircraft's position on the glide-slope path
• C. A system that provides audible guidance to pilots
• D. A device that measures wind speed

Answer: (B)

PAPI is a visual glide-slope indicator. It’s a small light system mounted beside the runway (usually on the left) that gives you a quick, color-coded cue about your position relative to the intended descent angle. As you approach, the lights help you stay on a precise glide path, typically around 3 degrees. If the lights show the pattern indicating you’re on the path, you’re at the correct angle; if the pattern shifts toward more red or more white, you’re too low or too high and you need to adjust your pitch. It’s purely a visual aid for approach alignment and does not involve radar guidance, audible signals, or wind measurements.