This is a working prototype for a PAPI landing guidance light set. Due to the fact that the halo effect of SP's beacon lights would become oversized at range (and thus overlap with each other), I turned it off, causing this to be only visible from about 1km away, instead of the IRL standard of 8km at day and 32 km at night.

How it works:
It works with an Aggressive AI trying to attack you (!?).
Yeah i know, it sounds weird, but here's how:
when an AI is aggressive, it would try to attack you, and thus it would try to fly towards you even if you put it in an entirely unflyable build.
This system uses exactly that.
The more you deviate from the runway surface, the more pitch input would be given by the AI trying to attack you. and it would move the light rack further away, exposing more white lights in the window.
Unfortunately this means we have to give this build a gun, because an unarmed "aggressive" AI will only try to evade you. Don't worry, I modded it and it doesn't do any damage at all. I tested that by putting my VBL in front of the gun and let it shoot at me whole day.

How to use it:
- Get a ground vehicle and drive to an appropriate location, usually left or right side off of the runway. Unlike the airfield builder, you don't have to be dead accurate, so you don't necessarily need to use that 50m relocator.
- Mark the spot as a spawn point.
- Fly your airplane
- Spawn an AGGRESSIVE AI "flying" this PAPI device at the location
- Use your airplane to land, try to keep the signal two red, two white, it should more or less mean you are on an appropriate approach path. Too many whites means you are too high, while too many reds means you are too low.

You may need to fine-adjust it to fit different approach paths and PAPI locations. You can't find two entirely identical approaches after all.
You can do so by modifying the blocks near the "window" and the movement amount of the piston. If you move the opening left, it would tend to show more reds, and vice versa. If you increase the piston movement amount it would be more sensitive, and vice versa.

KNOWN ISSUE:
The PAPI may show 4 whites instead of 4 reds, or worse, flashing between both, when you are very, very low in approach. This is because the AI's ground evasion command contradicts or overrides the targeting command. Unfortunately as long as this system is using targeting AI, this can not be completely resolved.

Also: Can we please have a tag for buildings and facilities and functional ground equipments like this one?