An Object Oriented Analysis Of Air Traffic Control

This appendix contains the object specifications for the Experiment model in alphabetical order. All classes in the Experiment model are identified in this specification; however, since most of the high-level classes are borrowed from the ATC model, and many of the attributes and services of the domain-unique classes are inherited from classes in the ATC model, only domain-unique components are defined. References are made to the ATC model and the AERA 2 model where necessary.

The format used is as follows:

class -

name (Identify referenced model where applicable)

structure -

an identification of the classes and objects directly above and beneath this class and its objects in a generalization-specialization or whole-part structure; unless otherwise stated, a generalization-specialization structure involves classes and a whole-part structure involves objects.

part of
contains parts
specialization of
generalization of

domain-unique instance connections -

an identification of each instance connection which is unique to the Experiment model.

domain-unique attributes -

name and a textual description of each attribute which is unique to the Experiment model.

domain-unique services -

name and a description (by bulleted list, service chart, or other device) of processing performed by each domain-unique service.

notes -

information about why this class was included in the Experiment model, or any other additional information about the class or object which is not already provided.

structure

specialization of Airspace Volume

domain-unique attributes

attribute Boundary - wedged-shaped airspace volume extending a full 90 minutes flying time starting outside the New York TRACON and extending southeast toward and past the Washington area airports.
attribute Demand (Inherited)
attribute Load (Inherited)
attribute Capacity (Inherited)

domain-unique services

None

notes

One of the six categories of airspace/ground-type resources identified as a testbed requirement in the experiment definition.

structure

part of Flight; Vehicle
contains parts Pilot; Vehicle Communications System; Vehicle Navigation System

domain-unique attributes

None

domain-unique services

None

notes

None

structure

specialization of Problem

domain-unique attributes

None

domain-unique services

None

notes

For the experiment, this class identifies one type of problem that AERA 2 will have to contend with in the en route airspace.

structure

specialization of Problem

domain-unique attributes

None

domain-unique services

None

notes

For the experiment, this class identifies one type of problem that AERA 2 will have to contend with in the en route airspace.

structure

specialization of Communications System
generalization of Data Link-Like Communications System; Voice Radio-Like Communications System

domain-unique attributes

None

domain-unique services

None

notes

None

structure

part of Airspace/Ground Resource
generalization of La Guardia Airport; Washington Area Airport

domain-unique attributes

None

domain-unique services

None

notes

For the experiment, airport movement areas were identified as sources and sinks of flights.

structure

specialization of Resource
contains parts Controlled Airspace; Airport Movement Area

domain-unique attributes

None

domain-unique services

None

notes

None

structure

specialization of Surveillance System
generalization of ARTS-Like Terminal Surveillance System; RDP-Like En Route Surveillance System

domain-unique attributes

None

domain-unique services

None

notes

None

structure

part of En Route Controlled Airspace
generalization of 90-Minute Flying-Time Wedge

domain-unique attributes

None

domain-unique services

None

notes

None

structure

specialization of Traffic
generalization of Experiment Scenario Traffic Pattern

domain-unique attributes

None

domain-unique services

None

notes

(1) The experiment is only interested in interactions associated with traffic in the air. Air traffic is defined in the experiment definition as traffic patterns descriptive of the AERA 2 time-frame. (2) The experiment model definition of the term "traffic pattern" is more general than the definition from the Federal Aviation Regulations: "the traffic flow that is prescribed for aircraft landing at, taxiing on, or taking off from an airport."

structure

specialization of Traffic Manager
generalization of Regional Air Traffic Manager

domain-unique attributes

None

domain-unique services

None

notes

None

structure

part of Flight Clearance

domain-unique attributes

None

domain-unique services

None

notes

Upon handoff from an en route controller to a terminal controller and receipt of the arrival clearance, the flight changes state from en route to arrival.

structure

specialization of Airspace Surveillance System

domain-unique attributes

None

domain-unique services

service Provide User Interface - provide the Plan View Display (PVD) with data blocks and conflict alert.
service Provide TAAS Capabilities

notes

Prior to the start of the experiment, the necessary radar data processing automation must be established in the terminal area. Terminal automation with TAAS capabilities and an ARTS-like user interface is specifically required by the experiment.

structure

generalization of Flight Clearance

domain-unique attributes

None

domain-unique services

None

notes

None

structure

specialization of Resource
contains parts Communications System

domain-unique attributes

None

domain-unique services

None

notes

None

structure

part of Communications Resource
generalization of Air/Ground Communications System

domain-unique attributes

None

domain-unique services

None

notes

None

structure

part of Airspace/Ground Resource
contains parts Enroute Controlled Airspace; Terminal Controlled Airspace

domain-unique attributes

None

domain-unique services

None

notes

None

structure

specialization of Air/Ground Communications System

domain-unique attributes

None

domain-unique services

service Provide Data Link-Like Services

notes

A Data Link-Like Communications System object provides a mechanism for electronic communications between the controller and the aircraft (pilot).

structure

part of Clearance

domain-unique attributes

None

domain-unique services

None

notes

Upon receipt of the departure clearance, the flight changes state from predeparture to departure.

structure

part of Clearance

domain-unique attributes

None

domain-unique services

None

notes

Upon handoff from a terminal controller to an en route controller and receipt of the en route clearance, the flight changes state from departure to en route.

structure

part of Controlled Airspace
contains parts Route; Airspace Volume

domain-unique attributes

None

domain-unique services

None

notes The Location attribute is of interest to the experiment since the meter fix points will be located on the boundary between the en route controlled airspace and the terminal controlled airspace.

structure

specialization of Flight Manager

domain-unique attributes

None

domain-unique services

service Identify Conflicts - AERA 2 service; three types of problems identified of interest to the experiment are aircraft-aircraft conflict, flow instruction non-compliance (meter fix violations only), and aircraft-airspace conflict.
service Propose Resolutions - AERA2 service; the highest-ranked resolution will always be delivered to and accepted by the aircraft.
service Compute Delay-Absorbing Maneuvers - this AREA 2 service will compute the delay-absorbing maneuvers.
service Handoff Aircraft to Terminal Controller - the automated en route controller will perform this service.
service Issue Delay-Absorbing Maneuvers - the automated en route controller will issue delay-absorbing maneuvers.

notes

For the experiment, the En Route Controller will be automated. The services described are identified in the experiment definition; however, the service names do not indicate whether the service is performed by the automated human controller or AERA 2.

structure

specialization of Air Traffic ("Traffic Pattern")

domain-unique attributes

attribute Demand - a unique number which represents the projected concentration of flights.

domain-unique services

None

notes

Varying the Demand attribute throughout the experiment allows the experiment interactions to vary: heavy demand results in many interactions, less demand results in less interactions.

structure

part of Route
generalization of Meter Fix

domain-unique attributes

None

domain-unique services

None

notes

None

structure

part of Air Traffic ("Traffic Pattern")
contains parts Aircraft; Flight Plan; Flight Clearance

domain-unique attributes

None

domain-unique services

None

notes

None

structure

specialization of Clearance
part of Flight
contains parts Departure Clearance; Enroute Clearance; Arrival Clearance

domain-unique attributes

None

domain-unique services

None

notes

None

structure

generalization of Enroute Controller; Terminal Controller; Tower Controller
specialization of Manager

domain-unique attributes

None

domain-unique services

None

notes

None

structure

part of Flight

domain-unique attributes

attribute Expected Meter Fix Time - expected time the flight will cross a meter fix.
attribute Expected Airport Arrival Time - expected time the flight will arrive at the destination airport.
attribute Flow Restriction Time - the time at which the flow restriction was issued.

domain-unique services

None

notes

The flight plan attributes identified are arrival times at the meter fix and at the destination airport. By running the metering program, these times are adjusted. The AERA 2 model contains a much more detailed description of the flight plan.

structure None

domain-unique instance connections

instance connection Flow Instruction (1) <-> Meter Fix (1)

domain-unique attributes

None

domain-unique services

None

notes

For the experiment, the only type of flow instruction is produced by metering.

structure

specialization of Problem

domain-unique attributes

None

domain-unique services

None

notes

For the experiment, the only type of flow instruction non-compliance is a meter fix time violation.

structure

specialization of Resolution

domain-unique attributes

None

domain-unique services

None

notes

For the experiment, the highest-ranked resolution is identified by AERA 2 and is always delivered to and accepted by the aircraft.

structure

specialization of Landing Navigation System

domain-unique attributes

None

domain-unique services

service Provide ILS Data to Aircraft.

notes

ILS navigational equipment on the ground is needed to communicate with the ILS navigational equipment on the aircraft, at La Guardia airport only.

structure

specialization of Terminal Route

domain-unique attributes

None

domain-unique services

None

notes

Predefined ILS routes will be identified in the La Guardia terminal area.

structure

specialization of Airport Movement Area

domain-unique attributes

attribute Arrival Capacity
attribute Departure Capacity
attribute Runway Configuration
attribute Expected Departure Rate

domain-unique services

None

notes

La Guardia Airport must be modelled with sufficient detail to permit a tower controller to coordinate departures with the terminal area arrival controller(s) so that the arrival stream is spaced appropriately to allow for departures. Aircraft on the ground will request departures at a rate consistent with the airport arrival capacity used by the metering program.

structure

specialization of Navigation System generalization of ILS-Like Landing Navigation System; MLS-Like Landing Navigation System

domain-unique attributes

attribute Type - ILS-Like or MLS-Like

domain-unique services

None

notes

None

structure

generalization of Traffic Manager; Flight Manager

domain-unique attributes

None

domain-unique services

None

notes

Base-level class of the Manager subject.

structure

specialization of Fix/Waypoint

domain-unique instance connections

instance connection Meter Fix (1) <-> Flow Instruction (1)

domain-unique attributes

attribute Location - somewhere on the en route and terminal area boundary

domain-unique services

None

notes

For the experiment, a meter fix is a fix or waypoint which resides at the boundary between the en route airspace and the terminal airspace to which aircraft are metered.

structure

specialization of Landing Navigation System

domain-unique attributes

None

domain-unique services

service Provide MLS data to aircraft.

notes

MLS navigational equipment on the ground is needed to communicate with the MLS navigational equipment on the aircraft, at La Guardia airport only.

structure

specialization of Terminal Route

domain-unique attributes

None

domain-unique services

None

notes

Predefined MLS routes will be defined in the La Guardia terminal area.

structure

contains parts Problem

domain-unique attributes

None

domain-unique services

None

notes

None

structure

specialization of Resource
contains parts Navigation System

domain-unique attributes

None

domain-unique services

None

notes

None

structure

part of Navigation Resource
generalization of Landing Navigation System

domain-unique attributes

None

domain-unique services

None

notes

None

structure

specialization of Terminal Airspace Volume

domain-unique attributes Boundary

domain-unique services

None

notes

The selected terminal area of interest is the New York TRACON. Meter fixes are located on the boundary, and arrival and departures of interest occur at La Guardia airport.

structure

part of Aircraft

domain-unique attributes

None

domain-unique services

service Receive/Implement Vectoring Instructions - this service can either be automated or performed by a simulated pilot (sim-pilot).

notes

En route pilot services are automated; terminal area services can either be automated or performed by a sim-pilot.

structure

part of Trajectory

domain-unique attributes

None

domain-unique services

None

notes

A point is a part of the trajectory created by AERA 2 to check for conflicts and meter fix time violations.

structure

part of Multiple Problem
generalization of Aircraft-Aircraft Conflict; Flow Instruction Non-Compliance; Aircraft- Airspace Conflict

domain-unique attributes

attribute Subject Aircraft - the aircraft for which the problem was detected.

domain-unique services

None

notes

None

structure

specialization of Airspace Surveillance System

domain-unique attributes

None

domain-unique services

service Provide Radar Data Processing (RDP) Services for En Route Airspace

notes

None

structure

specialization of Air Traffic Manager

domain-unique attributes

None

domain-unique services

service Adjust Flight Schedule - perform the metering program function of adjusting the schedule in response to problems. Adjustments may occur to allow for the inability of a flight to meet its meter fix time. Adjustments may include causing the metering program to create a new schedule based on the latest estimates of undelayed arrival times.
service Create Metering Flow Restriction - perform the metering program function of specifying the time a flight should cross a meter fix.
service Impose Flow Instruction - perform the metering program function of passing the meter fix times to AERA 2 as flow instructions.
service Sequence/Resequence Flight - perform the metering program function of flight sequencing, based on undelayed arrival times; resequencing may occur when adjustments are made to allow for the inability of a flight to meet its meter fix time.
service Monitor - performed by TMC

notes

The services are described from the experiment definition; however, the service names do not indicate whether the service is performed by a human or by automation - as far as the model is concerned, who or what performs the services is not important.

structure

generalization of Highest-Ranked Resolution (HRR)

domain-unique attributes

None

domain-unique services

None

notes

None

structure

generalization of Airspace/Ground Resource; Surveillance Resource; Communications Resource

domain-unique attributes

None

domain-unique services

None

notes

Base-level class of the Resource subject.

structure

part of En Route Controlled Airspace
contains parts Fix/Waypoint

domain-unique attributes

None

domain-unique services

None

notes

The experiment definition states that the current concept for traffic management in the AAS is that there will be a series of time control points (Fix/Waypoints in the ATC model) along a flights path (Route in the ATC model).

structure

part of Trajectory

domain-unique attributes

None

domain-unique services

None

notes

A segment is a part of the trajectory created by AERA 2 to check for conflicts and meter fix time violations.

structure

specialization of Resource
contains parts Surveillance System

domain-unique attributes

None

domain-unique services

None

notes

None

structure

part of Surveillance Resource
generalization of Airspace Surveillance System

domain-unique attributes

None

domain-unique services

None

notes

None

structure

part of Terminal Controlled Airspace
generalization of New York TRACON

domain-unique attributes

None

domain-unique services

None

notes

None

structure

part of Controlled Airspace
contains parts Terminal Route; Terminal Airspace Volume

domain-unique attributes

None

domain-unique services

None

notes

The Location attribute is of interest to the experiment since the meter fix point will be located on the boundary between the en route controlled airspace and the terminal controlled airspace.

structure

specialization of Flight Manager

domain-unique attributes

None

domain-unique services

service Final Arrival Sequencing and Spacing
service Coordinate Arrivals With Departures
service Accept/Initiate Handoffs

notes

For the experiment, one or two of the arrival positions will be staffed.

structure

part of Terminal Controlled Airspace
generalization of ILS Route; MLS Route

domain-unique attributes

None

domain-unique services

None

notes

None

structure

specialization of Flight Manager

domain-unique attributes

None

domain-unique services

service Coordinate Arrivals with Terminal Controller
service Coordinate Departures with Terminal Controller

notes

A tower controller is identified at La Guardia Airport to coordinate departures with the TRACON arrival controller (terminal controller in this model), so that the arrival stream is spaced appropriately to allow for departures.

structure

specialization of User
generalization of Air Traffic ("Traffic Pattern")

domain-unique attributes

None

domain-unique services

None

notes

None

structure

specialization of Manager
generalization of Air Traffic Manager

domain-unique attributes

None

domain-unique services

None

notes

None

structure

contains parts Point; Segment

domain-unique attributes

None

domain-unique services

None

notes

Trajectories are the projected aircraft paths determined by AERA 2 from flight plan information for the purposes of identifying conflicts and meter fix time violations. A trajectory is composed of a series of points and segments.

structure

generalization of Manager; Traffic

domain-unique attributes

None

domain-unique services

None

notes

Base class of the User subject.

structure

part of Aircraft

domain-unique attributes

None

domain-unique services

None

notes

None

structure

part of Aircraft

domain-unique attributes

None

domain-unique services

None

notes

None

structure

specialization of Air/Ground Communications System

domain-unique attributes

None

domain-unique services

None

notes

Voice radio-like communications are necessary in the terminal area for communication between terminal area controllers and sim-pilots.

structure

specialization of Airport Movement Area

domain-unique attributes

attribute Runway Configuration
attribute Expected Departure Rate

domain-unique services

None

notes

Washington area airports are contained in the 90-minute flying-time wedge and several of the other airspace categories defined in the experiment definition. These are identified as sources and sinks of flights.