If the elevation at the threshold is lower than the elevation at the uncorrected PAPI location, how should the PAPIs be moved?

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Multiple Choice

If the elevation at the threshold is lower than the elevation at the uncorrected PAPI location, how should the PAPIs be moved?

PAPIs are set so that, from the pilot’s viewpoint along the approach, the descent angle to the threshold matches a standard glide path (about 3 degrees). When the threshold elevation is lower than where the PAPI is located, keeping the PAPIs in place would produce a glide path that’s too shallow for a proper approach. Moving the PAPIs closer to the threshold increases the descent angle seen by the pilot, bringing the visual cue back toward the standard glide path. Lateral moves (left or right) don’t fix the vertical alignment, and moving farther away would tend to flatten the path further. So, the correct adjustment is to place the PAPIs closer to the threshold.

PAPIs are set so that, from the pilot’s viewpoint along the approach, the descent angle to the threshold matches a standard glide path (about 3 degrees). When the threshold elevation is lower than where the PAPI is located, keeping the PAPIs in place would produce a glide path that’s too shallow for a proper approach. Moving the PAPIs closer to the threshold increases the descent angle seen by the pilot, bringing the visual cue back toward the standard glide path. Lateral moves (left or right) don’t fix the vertical alignment, and moving farther away would tend to flatten the path further. So, the correct adjustment is to place the PAPIs closer to the threshold.

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