Why do airport codes change from green to purple on map?

Couldn’t find answer when I searched.

Green - VFR (Visual Flight Rules) more than 5 Nautical Miles of Visibility, Ceiling is greater that 3,000 Feet AGL.

Blue - MVFR (Marginal Visual Flight Rules) 3-5 Nautical Miles of Visibility, Ceilings are between 1,000 Feet and 3,000 Feet AGL.

Pink - IFR (Instrument Flight Rules) 3-1 Nautical Mile of Visibility, Ceilings are between 500 Feet and 1,000 Feet AGL.

Red - LIFR (Low Instrument Flight Rules) <1 Nautical Mile of Visibility, Ceiling is below 500 Feet.

DeerCrusher and Mark have some useful tutorials too:


If you are talking about the ICAO codes above the dots, if its green, it means ATC is active, if it isnt green, then there is no active ATC

The technical term would be uncontrolled for purple and controlled for green.

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Purple is uncontrolled. Blue is controlled airport but will have unicom when no ATC are present. The blue airports will also light up green when active ATC is there.

Blue Skies and A Tailwind,


Well I’ve seen controlled which are purple. Isn’t it weather in this case.

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Purple airports are not controllable. That would be an issue in the database

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