What does PAPI stand for in aviation technology?

The term PAPI stands for Precision Approach Path Indicator. This system is a visual aid used at airports to provide guidance to aircraft on the correct glide slope during an approach for landing. The PAPI consists of a series of lights positioned to the side of the runway. These lights indicate whether the aircraft is above, below, or on the proper glide path.

When a pilot is approaching the runway, the PAPI lights help them maintain the correct angle of descent, which is critical for safe landings. The lights change color based on the aircraft's position relative to the ideal glide slope; for example, if the pilot sees more white lights than red, it indicates they are too high, whereas more red lights indicate too low. This precise feedback is essential for ensuring adequate clearance over obstructions and achieving a safe touchdown point.

Understanding the correct terminology and functionality of PAPI is vital for pilots and air traffic controllers, as it directly impacts safety during the landing phase of flight. The other options do not accurately reflect the standard definition used in aviation.