The
Future Air Navigation System (
FANS) is an
avionics system which provides direct data link communication between the pilot and the
air traffic controller. The communications include air traffic control clearances, pilot requests and position reporting. In the FANS-B equipped
Airbus A320 family aircraft, an Air Traffic Services Unit (ATSU) and a
VHF Data Link radio (VDR3) in the avionics rack and two data link control and display units (DCDUs) in the cockpit enable the flight crew to read and answer the
controller–pilot data link communications (CPDLC) messages received from the ground.