Is there an approach light system called "APAP" that consists of lights?

I’m asking because I would like to log a bug report, but first, I would like to verify my question with the community.

The runway object SDK documentation has a picture of different approach light systems like VASIs and PAPIs:

#13 on that list is called “APAP.” There is a type of ALS called “APAP,” but that refers to a system of panels that may or may not be lighted that you have to line up while you’re flying in order to ensure you’re on the right glideslope. Here’s what they look like (starting at 0:57 in the video, you can see three yellow panels in the background for one runway and you’ll see two come into view in the foreground for the other side of that runway):

But #13 in that picture, above, shows two lights. I have never heard of APAP lights before. Do they exist? If not, or if there is doubt, I will log a bug report.

1 Like

Some supplemental info on APAP:

It’s basically a cheap VASI system as it doesn’t require any electricity and it’s fairly effective. It uses three brightly painted panels, the front two are elevated on poles, set at the nominal glidepath from the rear, middle panel, which is positioned on the ground, farther back from the front two. In conjunction, the parallax created by the juxtaposition of the panels shows whether the aircraft is on the glidepath.

There aren’t many certified installations remaining in the US (about a dozen airports), but I know there are more “unofficial” installations that don’t appear on the master database.

Here are a few photos of real-world installations:

Weaverville Pool Field, CA (O54) (uncharted unit)


Hummel Field, VA (W75)

The last is an older street view, the current overhead won’t show the installation because it’s been replaced by a P2L.

Also, slightly off-topic, but I’ve never seen a real-world example of #5 in @N316TS list. It seems very impractical. There used to be similar installations back in the day (especially at Air Force Bases) of what was known as a VASI 12, which was 3 + 3 units on each side of the runway.

Then, similarly, #6 is similar to 1/2 (one side) of a VASI16, but it’s upside down. The VASI16 was 2 + 3 + 3 on each side of the runway (from upwind to downwind), like the VASI12, but with the extra bar on the upwind side, designed for high-cockpit/long aircraft. But the extra bar was only two units per side, while the other two bars were three units per side. I say “was” because there are currently no VASI16 installations in the US (most 3-bar VASI have been replaced by PAPI4 units).

Here’s the diagram of how this all should look (including the APAP), which can be found in the legend of the US Terminal Procedures:

So if you’re fixing the APAP, can the others get some love as well?

Thanks for the pics! I was trying to look up pictures of APAPs, and the search results kept wanting to show me CPAPs. :smile::lungs:

Just a heads up that I’ll be logging a true bug report in a few days. I just want to solicit feedback before I do to make sure there isn’t some exotic 2-light system out there by the same name that I wasn’t aware of.