What is the purpose of Precision Approach Path Indicators (PAPI)?

Precision Approach Path Indicators (PAPI) serve the purpose of providing visual guidance for pilots during the landing phase of flight. These systems consist of a series of lights arranged in a specific configuration that indicate whether an aircraft is on the correct glide slope for landing. The visual cues help pilots ensure that they are descending on the appropriate angle towards the runway, which is critical for safe landings.

The PAPI system typically includes a combination of red and white lights; when the aircraft is too low, the lights appear more red, and when it is on the correct glide path, the lights will display a balance of red and white. If the lights show primarily white, it indicates that the aircraft is too high. By using this system, pilots obtain essential information that aids them in adjusting their approach, thus enhancing landing accuracy and overall safety.