Plain English Meaning
A closure that stays in place with no end date — the airport stays closed until someone officially says it's open again.
Full Definition
An airport or facility closure published with no scheduled reopening date, remaining in effect until a subsequent NOTAM or notice formally cancels it. UFN closures are typically issued for airports that are closed indefinitely due to construction, abandonment, loss of certification, or other long-term conditions, and they cause the airport's instrument approach procedures to be removed or restricted from charting and use.
Context Anchor
Seen in FAA airport information, charting updates, and instrument procedure discussions when an airport has been closed indefinitely.
Derivation
UFN stands for 'Until Further Notice.' The phrase 'until further notice' has been used in official notices for centuries to mean 'this stays in until we say otherwise.' The FAA adopted the abbreviation as shorthand for closures with no published end date.