Fake airports

[clanum 0]

I've noticed a couple of airports in North America that are modeled in the sim but don't actually exist. I wonder how something like this happens? While flying over southern Oregon, I noticed the AI called my position relative to KTUA which wasn't an airport I was familiar with despite knowing the area well. It showed on the sim's VFR map as being northeast of Klamath Falls, but a search on airnav showed that identifier isn't used, and a search on google maps shows no airport in that location at all. Thought it was just a fluke but today found "KTAK" west of Dillon, MT - the sectional shows nothing there, google maps shows no airport, and airnav says that identifier isn't used. So it appears there's a pattern, but I wonder what purpose this serves?

[aktorsyl 93]

I have quite a few of those in my area - they're mostly private airstrips on farms. In real life they don't have ICAO codes, but in the sim they do.