THE DATA BEHIND THE RADAR
More than dots on a screen.
Behind ADS-B Radar stands the extensive ACARSd aviation database: approximately 117 million recorded aircraft contacts, a continuously maintained flight-route database and individual aircraft records linked to their unique Mode-S addresses.
A LONG-RUNNING AVIATION PROJECT
The ACARSd database
Decades of aircraft observations. One connected source of aviation knowledge.
ADS-B Radar is more than a local receiver display. Its wider data ecosystem draws on the work behind ACARSd, a long-running aviation project dedicated to collecting, organizing and preserving aircraft information. The database contains around 117 million aircraft contacts — a substantial record of observed aviation activity.
Each contact represents an observation, not necessarily a different aircraft or flight. Together, these records provide a historical foundation for aircraft identification, route research and the ongoing improvement of aviation reference data.
AIRCRAFT IDENTIFICATION
From a six-character address to an aircraft
Every aircraft equipped with a Mode-S transponder uses a 24-bit ICAO aircraft address, commonly displayed as a six-character hexadecimal code such as 4D2022. ADS-B Radar uses this address as a key for looking up the corresponding aircraft record.
Our aircraft database brings together available identification and technical information, such as registration, aircraft type, manufacturer, construction or serial number, year of manufacture, engines and operator. The completeness of each record depends on the available and verified information; aircraft may change registration or operator over time, and data is reviewed and updated as new evidence becomes available.
This connection turns a raw radio message into something meaningful: instead of seeing only a hexadecimal address, an enthusiast can learn more about the actual aircraft behind it.
ROUTES AND FLIGHT NUMBERS
A flight database we actively maintain
An aircraft address tells us which airframe is transmitting. It does not, by itself, tell us where that aircraft is flying. That is why the ACARSd ecosystem also maintains a separate flight-route database, connecting known flight numbers and operational callsigns with departure and destination airports and, where applicable, intermediate stops.
Flight numbers and callsigns are not always identical, and the same aircraft may operate many different services. Routes can also change with schedules, seasons and operational circumstances. We therefore treat route information as maintained reference data rather than as an infallible real-time flight plan. Reports and corrections help us improve the quality of these records over time.
The result is a richer aircraft picture: radio reception provides the observation, the aircraft database provides the identity, and the flight database can add route context when a reliable match is available.
AIRCRAFT QUICKLINK
One aircraft. One simple address.
We wanted aircraft information to be easy to reach and easy to share. That is the idea behind Aircraft QuickLink: enter an aircraft’s ICAO24 address directly as a subdomain of adsb-radar.org to open its dedicated aircraft page.
For example, 4D2022.adsb-radar.org leads to the aircraft record associated with Mode-S address 4D2022. No complex search form and no long database URL are needed. QuickLinks are useful for spotters, aircraft researchers, receiver operators and anyone sharing a particular airframe with a friend.
The ICAO24 address identifies the transponder address, while the registration shown in the database reflects the information associated with that address. Records may evolve as registrations or ownership change, and historical observations should always be interpreted in their proper time context.
TRY AN AIRCRAFT QUICKLINK
Three aircraft. Three direct links.
Select any example below to open its aircraft page. The six-character Mode-S address is the entire subdomain.
CONNECTED, NOT DEPENDENT
Local radar reception. A broader knowledge base.
ADS-B Radar receives and decodes aircraft signals locally through libadsb-reader. The wider ACARSd database complements this local reception with reference and historical information. It is not necessary to have an account or contribute data simply to use the radar.
Our aim is to make aircraft data more accessible while preserving the distinction between what a receiver actually observed, what reference records identify and what route information can reliably establish. As the database grows and is corrected, the Aircraft QuickLink pages provide a convenient entry point to that knowledge.