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Flashcards in FANS Deck (18):

FANS (Future air navigation system) was developed by ICAO to....

Allow more A/C to safely and efficiently utilise a given volume of airspace as ICAO predicted the growth of air travel and attendant increase in demands made upon the airspace available.


The systems that can be connected to the communication management unit (CMU), are....

• Multipurpose control and display unit (MCDU)
• Communication unit (VHF, HF, SATCOM)


Comparing the media used to transmit datalink comms, the appropriate classification to the fastest data transmission rate is....

HF datalink, VHF datalink, SATCOM


Which datalink communication cannot be used in the polar regions?

Of the 3 used, SATCOM can't be used in the polar regions as the geostationary satellites are at the EQ and so outside it's limits.

VHF is Range limited so only HF is left and can be used as the lower freq allows the waves to bend round curvature of earth.


ADS is a FANS application performed:

Automatically without any crew action to define the set of data to downlink or the type of report contract.


What are FAN routes?

FANS uses datalink comms to maximise airspace use and to min fuel burn by reducing necessary climbs and permitting direct routing, thus no specific or numbered routes.

Fundamental use of FAN routes is that ANP (actual nav perf) must be better than RNP (required nav perf).

FAN routes are currently not used in high density areas as the system is not mature enough and so are used mainly over oceanic areas.


What are CPDLC and ADS, and what are their differences?

• Controller pilot data link communication (CPDLC):
This is communication with ATC via ACARS.

• Automatic dependent surveillance (ADS):
Must log on called Airways facilities notification (AFN)
The A/C avionics automatically report back to ATC


ADS (automatic depended surveillance) has 3 types of contracts, what are they?

• Periodic: a report is sent back to ATC every 'period' as
requested by ATC. This mode also performs automated hand
off to the next ATCU (unit). Contracts remain valid until cancelled or

• Events: a report is send after a change in certain parameters e.g.
LDG, flight level change, speed

• Demand: one off request by the ATC unit for specific pieces of info
e.g. Position report

Emergency mode - activated by the pilots only


On data link comms, a downlink can be a flight event reporter, OOOI. What does this stand for?

Out of gate, out of ground, on the ground, in the gate.


Datalink ACARS services are provided via?



Benefit of Datalink using satellite over HF is?

Satellite use space waves which eliminated ionosphere interference and has a faster transmission speed.


CPDLC stands for?

Controller Pilot Data Link Communications


The on board data link equipment can include:

• ATC visual annunciator
• Printer


Under FANS, there exists an ICAO:

Communication, Navigation, Surveillance/Air traffic management (CNS/ATM) concept


FANS 1/A uses the ACARS network whereas

FANS 2/B uses the ACARS network and ATN


ADS systems depends is...

ATC surveillance which is dependant upon automated downlinked aircraft reports


An ATCU can use:

The ADS application only, or the CPDLC application only, or both of them (not including AFN).


During the log on process (AFN) with an ATCU, an A/C passes the following typical data:

• Flight number
• Registration
• Supported Avionics
• Version numbers
• ACARS addresses