FANS (CNS:ATM)

Question 1

ACARS can operate on 3 different frequencies, what are they?

Answer 1

VHF- primarily used
HF-USED FOR OPERATION OVER THE POLES
SATCOM- USED AS A BACKUP.

WHEN OUT OF VHF RANGE, A SATELLITE SHADOW AREA MIGHT LEAD TO A LOSS OF SATCOM CAPABILITY LEAVING HF THE ONLY FREQUENCY FOR ACARS TO OPERATE ON

Question 2

Three ACARS system components:

Answer 2

1. Management unit/ communications management unit (MU/CMU)
2. Datalink Service Provider
3. Ground Processing System

Question 3

3 types of messages sent between aircraft and ground station ACARS

Answer 3

1. Air traffic control (ATC)
2. AERONAUTICAL OPERATIONAL CONTROL (AOC)
3. AIRLINE administrative control (AAC)

Question 4

CPDLC

Answer 4

Controller-Pilot data link communications.
A system in which the ATC and flight crew are able to communicate with each other over a data link system. Is utilized by ACARS but is also a separate system, mainly used to communicate with ATC.

Question 5

Satellite communication System (SATCOM)

Answer 5

A system that uses a network of four geostationary satellites located above the equator to provide virtually worldwide coverage (except poles). Satellites owned by INMARSAT and one supplemented by Japan civil aviation bureau (JCAB)
NOTE NOT ABLE TO BE USED OVER THE POLES. When OUT OF VHF RANGE ANY SATELLITE SHADOW MAY LEAD TO A LOSS OF SATCOM CAPABILITY

Question 6

ADS-C

Answer 6

Automatic Dependent Surveillance.
A system that works on the basis that it will set up a contract with the aircraft, requiring this aircraft to send information automatically to a ground station at specified intervals

Question 7

ADS-B

Answer 7

Automatic Dependent Surveillance-Broadcast.

Predicted to replace radar as primary method for controlling aircraft worldwide. Enhances aviation infrastructure and safety by making aircraft visible in real time to ATC and other ADS-B aircraft with position and speed data transmitted every second.

ADSB IN AND ADSB OUT.

ADSB-IN receives information by the traffic information services (TIS) and flight information services (FIS) and also other information by direct communications from nearby aircraft.

Question 8

3 ADS-C contracts

Answer 8

1. Periodic contract, information transmitted at periodic term intervals
2. Event contract-information is transmitted between a certain event occurs for example vertical rate change, lateral deviation, or waypoint change.
3. Demand contract-the information is transmitted in a one-off request.

Question 9

MLAT - multilateration

Answer 9

Similar to GPS however MLAT uses receiver stations placed at strategic locations around an airport.
TWO-DIMENSIONAL POSITIONING REQUIRES THREE RECEIVER STATIONS, THREE-DIMENSIONAL POSITIONING REQUIRES FOUR RECEIVER STATIONS.

VERY HIGH UPDATE RATE, ABOUT 1 PER SECOND MAKES MOVEMENT ACROSS SCREEN FAR MORE USEFUL FOR ATC THAN RADAR (4-12 SECOND)

ONLY REQUIREMENT IS THAT AIRCRAFT BE FITTED WITH MODE A/C/S TRANSPONDER

Question 10

MLAT basic description

Answer 10

Similar to GPS however utilizing receivers around an airport to provide aircraft position to ATC. Much faster update rate than radar (1 per second)

Question 11

ADS-C

Answer 11

Automatic dependent surveillance- contract.
Information being sent from the aircraft under the contract without any knowledge from flight crew or extra workload. Cannot be modified by flight crew.
has the capability of communicating with four ground stations simultaneously plus the airline’s control center.

Like ADS-B, ADS-C uses GPS and adsc unit.