Cartoon: Eddie hears about FANS, from Eddie's notebook.

Eddie Sez:

I was a staff officer at the Pentagon when I first heard about FANS and thought it was madness. It was envisioned as a system that completely revolutionized communications, navigation, and surveillance when flying anywhere in the world and, in 1992, it sounded like science fiction. Three years later the Boeing Aircraft Company came up with a way to do the communications part and that became FANS-1. A few years later Airbus did their version and that was known as FANS-A. Now we have a few variants but they are basically called FANS-1/A and you must have FANS-1/A to fly in some parts of the world. So what is FANS-1/A?

It is basically nothing more than a CPDLC system that uses the ICAO Aeronautical Telecommunications Network (ATN) over Satcom or VHF and Automatic Dependent Surveillance – Contract (ADS-C) as specified by the ICAO. You can read more about those here:

Oh yes, that other stuff. Yes we have realized much of the science fiction with other aspects of Performance Based Navigation but they are not a part of FANS-1/A.

What follows are quotes from the relevant regulatory documents, listed below, as well as my comments in blue.


[ICAO SVGM, pg 1-14] Future air navigation system 1/A — As defined by [Radio Technical Commission for Aeronautics] RTCA DO-258A / [European Organization for Civil Aviation Equipment] EUROCAE ED-100A, or previous standards that defined the FANS 1/A capability. FANS 1/A generally means that the data link system on an aircraft, the [Air Traffic Service Unit] ATSU ground system, and communication service provision comply with the standard. In certain cases, specific reference is made to a particular type of FANS 1/A aircraft as follows:

  1. FANS 1/A+ means that the aircraft completely complies with Revision A of the standard, which includes message latency timer; and

  2. FANS 1/A ADS-C means that the aircraft complies with data link initiation capability and ADS-C applications, but does not include the CPDLC application.

[ICAO GOLD, table 2-1]

FANS mandates were a big deal about ten years ago, with everyone fretting on how they were going to comply. Most of the mandatory dates have come to pass and you will be denied some airspace throughout the world if you are not FANS compliant. But you hardly ever see that terminology any more. The mandatory requirements are given for CPDLC and ADS-C. That is where your focus needs to be.


[ICAO SVGM, pg vi]

[ICAO Doc 9613, pg. I-(xii)]

It is true that Required Navigation Performance Capability (RNPC) was changed to Required Navigation Performance (RNP). But there is more to it that that. We also have Required Communications Performance (RCP) and Required Surveillance Performance (RSP).

Book Notes

Portions of this page can be found in the book International Flight Operations, Part III, Chapter 3.


ICAO Doc 9613 - Performance Based Navigation (PBN) Manual, International Civil Aviation Organization, 2008

ICAO Global Operational Data Link Document (GOLD), International Civil Aviation Organization, Second Edition, 26 April 2013

ICAO Satellite Voice Guidance Material (SVGM), International Civil Aviation Organization, First Edition, 24 July 2012