What do all white lights on a PAPI recommend to the pilot?

When all the lights in a Precision Approach Path Indicator (PAPI) are white, it indicates that the aircraft is too high above the desired glide slope for a safe approach to landing. The PAPI is designed to provide visual guidance to pilots during the approach phase by presenting a combination of red and white lights. Specifically, having all white lights signifies that the plane needs to descend to achieve the correct glide slope angle.

Understanding the functions of the PAPI lights is crucial for pilots, as they rely on this information to ensure a safe landing approach. The other alternatives would not provide an accurate interpretation of an all-white indication. For instance, being at the correct glide slope would yield a mix of red and white lights, while maintaining current altitude or being on approach cannot specifically be deduced from an all-white light configuration.