Precision approach path indicator

You'll see approach lighting system designations that reference configuration types.

You'll see notations for precision approach path indicators, what most pilots know as PAPI, and visual approach slope indicators.

Runway end identifier lights, centerline lights, touchdown zone lights, all of it has a specific code on the Jeppesen ten-nine.

Here’s my strong recommendation: before you fly Jeppesen charts operationally, open the Jeppesen chart introduction section, the one that comes at the front of the binder before any of the actual charts, and spend thirty minutes with the lighting legend.

Now here's where it gets more nuanced.

The Visual Glide Slope Indicators, the Visual Approach Slope Indicator, or VASI, and the Precision Approach Path Indicator, or PAPI, are designed to put you on a path that intercepts your aim point, not your touchdown point, your aim point.

When you see two white lights and two red lights on a four-light PAPI system, you're on a path that, if maintained, will bring you precisely to the aim point for that runway.

The flare then does its job and moves you into the touchdown zone.

This is why, if you're high on the PAPI all the way down final and you're still seeing four whites, you might touchdown long.

The system was telling you the whole time.

You just didn't correct back to the correct glide path.

This is also why the phrase on glide slope, on speed, in the flare matters so much as a sequence.