Definition
An ADS-B (Automatic Dependent Surveillance-Broadcast) status indication meaning the aircraft's transmitted position data does not meet the required accuracy or integrity standards for use in air traffic control separation, but the system is not actively warning the pilot or controller about the degraded data. The position is still being broadcast, but it is not trustworthy for ATC purposes, and no alert has been generated to flag this condition.
Plain English
The aircraft's position signal is not reliable enough for controllers to use, but no warning has been raised about it. The data is going out, just not at a quality the system can trust — and nobody is being told.
Context Anchor
Seen in FAA surveillance, automation, or traffic-display documentation rather than as a normal pilot radio phrase.
Derivation
"Invalid" comes from Latin invalidus, meaning "not strong" or "not having force." Here it means the data lacks the strength (accuracy/integrity) to be used. "Non Alert" simply means no alert is being issued. Together: the data is not good enough to use, and the system isn't flagging it.
Why Pilots Care
Tells the pilot that traffic or terrain awareness data may be incomplete, requiring extra visual scanning or ATC confirmation.
Grounding Statement
Picture a traffic item on a display that the system cannot trust enough to use, but that has not reached the level of a warning.
Intuition Check
Invalid does not mean the aircraft itself is illegal or unsafe. Non Alert does not mean the data is good; it means the system is not treating it as an active warning at that moment.
Example Sentence 1
The controller advised the pilot that radar contact was lost because the ADS-B output had dropped to Invalid Non Alert.
Example Sentence 2
When Invalid Non Alert appeared during the approach, the crew requested traffic advisories from ATC.