ADS-B Out, CPDLC & FANS-1/A Explained

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ADS-B Out, CPDLC and FANS-1/A are all systems that are featured in modern aircraft for communication, navigation and surveillance purposes- especially in areas where traditional comms and radar doesn’t work. Here’s how each system works and what they’re used for:

ADS-B Out

ADS-B Out stands for Automatic Dependent Surveillance- Broadcast Out. Essentially it is a radio broadcast that gives aircraft position and velocity information to ATC (Air Traffic Control) and other nearby aircraft. It uses GPS (Global Positioning Systems) to determine aircraft position. And if you haven’t guessed it yet, yes, there is also ADS-B In which receives data rather than broadcasting out.

ADS-B is important for situational awareness and is required in the United States and many other countries for operating in controlled airspace. You can think of ADS-B as the baseline communication requirement.

CPDLC

Controller-Pilot Data Link Communications- or CPDLC- is a digital, text-based communication system between ATC and the flight deck. CPDLC is required when flying at high altitudes over remote airspace, across transatlantic and transpacific routes and over congested European airspaces.

CPDLC is great for decongesting busy radio frequencies especially on long-haul flights. CPDLC also offers clearer, less error-prone comms than by voice. This is due to the pre-programmed standardized messages, less overlapping of transmissions and less confusion when it comes to accents. This also helps your flight crew by reducing pilot work-load.

FANS-1/A

FANS-1/A means Future Air Navigation System, where 1 is Boeing’s implementation and A is Airbus’ implementation even though they’re the same thing. You guessed it! 1/A meets both Boeing and Airbus standards.

FANS-1/A is a package that includes CPDLC and ADS-C. It’s mainly used in oceanic airspace and is required for reduced separation- or the practice of allowing aircraft to fly closer together than standard traffic spacing requirements.

  • ADS-B and ADS-C function differently, even though both are categorized as Automatic Dependent Surveillance.

    ADS-C transmits data only when a contract is established with a specified ATC center. These transmissions are sent only to the designated ATC facility and are not available publicly. ADS-B continuously broadcasts position and flight data publicly to anyone equipped to receive it as well as sites like Flight Radar.

    ADS-C is mainly used in non-radar, remote, or oceanic airspace, whereas ADS-B is used in domestic, radar-surveilled airspace, adding to or replacing radar surveillance.

    ADS-C typically uses satellite communication (SATCOM) or high frequency (HF)/very high frequency (VHF) data link, depending on location and equipment. ADS-B, on the other hand, uses terrestrial radio frequencies (1090 MHz or 978 MHz) for transmission.

If you’re buying, selling or upgrading an aircraft, it’s important to know the roles of ADS-B, CPDLC and FANS-1/A and the capabilities of your aircraft. Ensuring your plane is future-proof, globally operable and has optimal efficiency protects your investment.