Air Traffic
Management
Calie Giangi
Agenda
• Introduction to ATC
• Purpose
• Basic Services
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Generic Elements
Airspace
ATC Structure
ATC Operations
Future of ATC
Air Traffic Control (ATC)
• Also known as air traffic management (ATM)
• The purpose of ATC is to ensure the safe and efficient flow of
air traffic
Four Basic Services
• Separation assurance – ATC controllers are responsible for
keeping aircrafts separated from each other, as well as from
other hazards such as terrain or wake vortices
• Flight information – provide weather and airport condition
updates
• Search and rescue – notifying and alerting proper agencies
about an aircraft in need
• Congestion management – organizing traffic flows into
congested airports and airspace
Generic Elements of ATC System
Generic Elements of ATC System
• Communications System
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Commands/clearances are issued to aircrafts
Voice radio channels
Network of ground stations
Range is limited to 100 nautical miles
XM/Sirius are used to send non-aircraft-specific data
Generic Elements of ATC System
• Navigation Systems
• ATC controllers ensure aircrafts fly a cleared route
• En route
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Long-range coverage
VHF omnidirectional range system (VOR system)
Limited to line of sight communication
Stations located at/near airports or on high ground
• Approach
• Higher precision required
• Runway classification: non-instrument (visual) vs. instrument
Generic Elements of ATC System
• Surveillance Systems
• ATC controller observes and monitors traffic situations
• Position reporting – crew communicates its position
• Radar – currently used for most domestic systems
• Primary Radars – measure range by the round-trip time of an
interrogation pulse reflected off of the aircraft
• Secondary Radars – aircraft is equipped with a transponder which
receives and transmits an interrogation pulse along with an ID code
for the responding aircraft (ATC Radar Beacon System)
• Direction (antenna) and altitude (ATCRBS) are also measured
Generic Elements of ATC System
• Flight and Weather Information Systems
• Flight plans are managed in a central flight data processing
system, distributed to various ATC facilities
• Increasing number of computer-based decision support tools are
being developed to help controllers optimize the flow of traffic
• Current conditions provided to pilots and ATC controllers
• Extensive weather information systems generate and distribute
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general and airport-specific forecasts and observations
winds aloft forecasts
hazardous weather alerts
pilot reports (PIREPS)
Airspace
• Controlled
• Traffic is supervised and managed by ATC
• Uncontrolled
• Aircrafts not directly managed by ATC
• Military operations
• Airspace is reserved for military
• Civilian aircrafts are prohibited from entering or require
permission from military authorities before using it
ATC Structure
• Ground Control
• Manages aircraft and other vehicles on airport surface as they
taxi to/from the runway
• Tower Control
• Manages take off and landing
• Radius of about 5 miles from the airport and 2500-3000 ft high
• Terminal Airspace Control
• Manages descent, initial approach, and departure phases
• En route/Center Control
• Manages traffic above and between terminal airspace
• Oceanic/International Airspace
• Managed by International Civil Aviation Organization (ICAO)
ATC Operations
• Human-centered contract process
• Controllers and flight crews negotiate for access to airport or
airspace resources
• ATC controller observes traffic situation through surveillance
system
• Controller issues commands to aircraft
• Standard Operating Procedures
• Altitude (east vs. west)
• Holding patterns to delay aircraft in air when high traffic makes it
difficult to move to the next sector
• Priority for and equity of service (usually FCFS)
• Emergencies/Equipment failures
Future of ATC Systems
• Not much room for growth in US
• Early plans include
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Increased use of satellite navigation systems
Surveillance systems based on ADS-B
Use of time as a control parameter in trajectory-based clearances
Broad information sharing through system-wide information
management
• Moving controllers to a more supervisory role and shifting some
ATC functions to the cockpit