Definition
A nationwide FAA telecommunications network used to exchange aeronautical and air traffic data between FAA facilities, airlines, and other authorized users. NADIN II is the upgraded version of the original NADIN system and handles the routing of flight plans, weather data, NOTAMs, and other operational messages across the National Airspace System.
Plain English
It is the FAA's data network — the digital backbone that moves flight plans, weather, and NOTAMs between control facilities and operators across the country.
Context Anchor
Seen in FAA acronym and NOTAM contraction lists, especially when the material is referring to the systems that distribute official aviation information.
Derivation
Named for its function: National Airspace Data Interchange Network. The 'II' indicates this is the second-generation system, replacing the original 1970s-era NADIN.
Why Pilots Care
When a pilot files a flight plan or pulls a weather briefing, the request and the response travel over NADIN II. Most pilots never interact with it directly, but it is what makes flight plan routing and NOTAM delivery work behind the scenes.
Intuition Check
Do not read NDNB as a cockpit instrument or navigation aid. In this FAA context, it points to an information-distribution network, not equipment installed in the airplane.
Example Sentence 1
Filed flight plans are routed through NADIN II to the appropriate ATC facilities.
Example Sentence 2
NADIN II updates are received automatically at most flight service stations.