Definition
A NOTAM contraction indicating that a facility, service, runway, navigation aid, procedure, or piece of equipment is not available for use during the period stated in the notice.
Plain English
A short way of saying 'you can't use this right now.' It tells pilots that something they might normally count on — a runway, a light, a navigation aid — is out of service for a stated time.
Context Anchor
Seen in preflight aviation notices and airport information, especially when a runway, taxiway, light, service, or navigation facility cannot be used.
Derivation
UNAVBL is a shortened aviation-notice form of unavailable. Unavailable means “not available,” with un- meaning “not.” In aviation notices, the shortened form saves space while still warning the pilot that something cannot be used.
Why Pilots Care
Pilots must identify UNAVBL items during preflight planning to avoid relying on unavailable navigation aids or services that could compromise safety.
Intuition Check
UNAVBL does not always mean something is physically gone or permanently broken. It means it is not available for use under the stated notice.
Example Sentence 1
The NOTAM showed runway 27 lights UNAVBL between 0200 and 0500 local, so we planned to land before then.
Example Sentence 2
The pilot checked that the fuel truck was not UNAVBL before taxiing to the ramp.