ACARS (Aircraft Communications Addressing and Reporting System)

A digital datalink system that enables the transmission of text-based messages between an aircraft and ground stations. ACARS is used to send both ATC-related messages (such as departure and oceanic clearances) and AOC (Airline Operational Control) messages (such as weather updates, gate assignments, and maintenance data). It operates over VHF, HF, or satellite communication (Satcom) links and is managed through the aircraft’s Communication Management Unit (CMU), which connects to the FMS and the Multipurpose Control & Display Unit (MCDU). ACARS reduces voice congestion on radio frequencies by allowing routine communications to be handled digitally.