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(FANS) Future Air Navigation System

FANS 1/A is a protocol for safely managing the expected increases in the volume of air traffic in the coming years. FANS 1 was developed by Boeing and later adopted by Airbus (FANS A). FANS 1/A uses an early version of both systems and has been used for 15 years by the airlines.

There are two parts to FANS. One is ADS-C, which is Automatic Dependent Surveillance Contract, and one is CPDLC, which is Controller Pilot Data Link Communication.

(CPDLC) Controller Pilot Data Link Communication

Controller Pilot Data Link Communication allows Satelite based two-way, digital communication between a controller and a pilot when an aircraft is out of range of traditional analog very high frequency (VHF) or high frequency (HF) voice-radio communications. As with terrestrial-based messaging between cell phones, the air traffic controllers and the flight crews communicate via text messages. The CPDLC application has three primary functions:

  • Facilitates the exchange of messages between the pilot and the ATC who is currently in control of the aircraft.
  • Clarifies dialogue between ATC and the aircraft crew who speak different languages (removes the accent from the picture because all communication is text-based).
  • Allows the crew to review ATC instructions.

ADS-C Automatic Dependent Surveillance - Contract

With ADS-C, there are three types of contracts that can be set up by your controller.

Like the name suggests, periodic contracts are time-based and can be varied by air traffic controllers depending on their needs. With an event contract, Air Traffic Control (ATC) sets it up so that if your aircraft deviates in altitude, vertical speed, or several other different parameters that they predesignate and they're notified of it immediately. Demand contracts are typically used when ATC wants to know where everybody is right now, and they'll initiate a contract and everyone will reply. There is one more type of contract, but this contract unlike the previous three is not set up by ATC, it's controlled by the pilot. This is initiated with a mayday message.

With FANS and the ADS-C aspects of automatic position reporting, air traffic control can set up under a periodic contract how often they want a report on an aircraft so they can monitor it at all times.

LINK 2000+

The LINK 2000+ Program is coordinating the European implementation of CPDLC in upper airspace.