An Object Oriented Analysis of Air Traffic Control: Appendix A

An Object Oriented Analysis Of Air Traffic Control

Celesta Ball
Rebecca Kim
WP 90W00542
August 1991
Approved for public release, distribution unlimited
MITRE Corporation, McLean, Virginia
Table of Contents

APPENDIX A
ATC MODEL SPECIFICATIONS

This appendix contains the class and object specifications for the ATC model. The specifications are ordered by class name, and are formatted as follows:

class -
name and a general description of the class and its objects. A source, such as the Airman's Information Manual (AIM), might be given.

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

instance connections -
an identification of the instance connections between an object of the class and other objects.

message connections -
an identification of the message connections between this class or object and other classes or objects; unless otherwise stated, the message is between objects. Messages requesting intrinsic services are not identified.

object states -
an identification (in text, a table, a state transition diagram, Petri net, etc.) of the states and transitions between states of an object, possibly including attribute values associated with achieving each state.

attributes -
name and a textual description of each attribute, which might include constraints (e.g., default values, the impact of the values of other attributes) on its value.

services -
name and a description (by a bulleted list, service chart, or other device) of the processing performed by each service, including (when necessary) an identification of the object states associated with the service and/or how the service behaves differently depending on the state of the object.

external inputs -
information provided by sources external to the domain of study.

external outputs -
information provided to entities external to the domain of study.

notes -
additional information about the class or object which is not already provided.

specification ACF Airspace - the airspace controlled by an area control facility.

structure
specialization of Airspace Volume
contains parts Sector

instance connections
instance connection ACF Airspace (0, m) <-> Flight (0, m)
instance connection ACF Airspace (0, m) <-> Aircraft (0, m)
instance connection ACF Airspace (0, m) <-> Flight Manager (0, m)
instance connection ACF Airspace (0, m) <-> Air Traffic Manager (0, m)
instance connection ACF Airspace (0, m) <-> Traffic Manager (0, m)

message connection
Intrinsic only

object states
None

attributes
attribute Capacity (see Airspace/Ground Resource)
attribute Configuration (see Airspace/Ground Resource)
attribute Demand (see Airspace/Ground Resource)
attribute Load (see Airspace/Ground Resource)
attribute Location (see Airspace/Ground Resource)
attribute Name (see Airspace/Ground Resource)
attribute Saturation Threshold (see Airspace/Ground Resource)
attribute Separation Minima (see Airspace/Ground Resource)
attribute Usage Restrictions (see Airspace/Ground Resource)

services
The ACF Airspace class performs the implicit services create, connect, and release. An ACF Airspace object performs the implicit service access.

service Update Demand

Update the value of the Demand attribute to reflect the addition, change, or deletion of an instance connection.

service Update Load

Update the value of the Load attribute to reflect the addition, change, or deletion of an instance connection.

external input
None

external output
None

notes
None

specification Aircraft - device(s) that are used or intended to be used for flight in the air. (AIM, 1991)

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

instance connection
Aircraft (0, m) <-> airspace-type resource [1, m)

message connection
Create Flight Object, sent to Flight class

object states
An Aircraft object has two states, airborne and not airborne, as determined by the value of its attribute Location.

attributes
attribute Aircraft Identification - a unique identification; the radio call sign.

attribute Location - the position of the aircraft as known by ATC, whether determined by ATC or reported to ATC by the aircraft itself and recorded by ATC. Location includes lateral and vertical dimensions and time.

services
The Aircraft class performs the implicit services create, connect, and release. An Aircraft object performs the implicit service access.

service create

Create and initialize, as specified for the implicit service create.
When an Aircraft object is created and there does not already exist a Flight object of which the Aircraft object is to be a part, requests the Flight class to create a Flight object of which the Aircraft object is a part.

external input
None

external output
None

notes
The AIM definition also adds "and when used in air traffic control terminology, may include the flight crew." However, in ths model, the flight crew is described separately and only the pilot is of interest.

specification Air/Ground Communications System - a system of communications media provided by the ATC system for the transfer of information between the ATC system and aircraft and the management of the information.

structure
specialization of Communications System

instance connection
Air/Ground Communications System (0, m) <-> Vehicle Communications System (0, m)

message connections
message Request Accept Message, to manager-type object
message Request Accept Message, to Vehicle Communications System
message Request Transmit Message, from manager-type object
message Request Transmit Message, from Vehicle Communications System

object states
None

attributes
attribute Area of Coverage (Inherited)
attribute Equipment Type (Inherited)
attribute Status (Inherited)

services
The Air/Ground Communications System class performs the implicit services create, connect, and release. An Air/Ground Communications System object performs the implicit service access.
service connect (Inherited)
service Transmit Message (Inherited)

external input
None

external output
None

notes
Specializations of the Air/Ground Communications System class could be created to distinguish between communications by voice radio and communications by data link.

specification Airport Movement Area - all taxiways, runways, and other areas of an airport that are used for taxiing, takeoff, and landing of aircraft, exclusive of loading ramps and parking areas. (Springen, 1989)

structure
part of Airspace/Ground Resource
contains parts Runway; Taxiway; Holding Area

instance connections
instance connection Airport Movement Area (1) <-> Vehicle (0, m)
instance connection Airport Movement Area [1, 2) <-> Aircraft (0, m)
instance connection Airport Movement Area (0, 1) <-> Vehicle Manager (0, m)
instance connection Airport Movement Area (0, m) <-> Ground Traffic Manager (0, m)
instance connection Airport Movement Area (0, m) <-> Traffic Manager (0, m)

object states
None

attributes
attribute Airport Identification - the identification of the airport
attribute Capacity (see Airspace/Ground Resource)
attribute Configuration (see Airspace/Ground Resource)
attribute Demand (see Airspace/Ground Resource)
attribute Load (see Airspace/Ground Resource)
attribute Location (see Airspace/Ground Resource)
attribute Name (see Airspace/Ground Resource)
attribute Saturation Threshold (see Airspace/Ground Resource)
attribute Separation Minima (see Airspace/Ground Resource)
attribute Usage Restrictions (see Airspace/Ground Resource)

services
The Airport Movement Area class performs the implicit services create, connect, and release. An Airport Movement Area object performs the implicit service access.

service Update Demand

Update the value of the Demand attribute to reflect the addition, change, or deletion of an instance connection.
service Update Load

Update the value of the Load attribute to reflect the addition, change, or deletion of an instance connection.

external input
None

external output
None

notes
None

specification Airport Radar Services Area - ARSA; regulatory airspace surrounding designated airports wherein ATC provides vectoring and sequencing on a full-time basis for all IFR and VFR aircraft. The service provided in an ARSA is called ARSA service which includes IFR/IFR standard separation, IFR/VFR traffic advisories and conflict resolution, and VFR/VFR traffic advisories and, as appropriate, safety alerts. (AIM)

structure
specialization of Terminal Airspace Volume

instance connections
instance connection Airport Radar Services Area (0, m) <-> Flight (0, m)
instance connection Airport Radar Services Area (0, m) <-> Aircraft (0, m)
instance connection Airport Radar Services Area (0, m) <-> Flight Manager (0, m)
instance connection Airport Radar Services Area (0, m) <-> Air Traffic Manager (0, m)
instance connection Airport Radar Services Area (0, m) <-> Traffic Manager (0, m)

message connection
Intrinsic only

object states
None

attributes
attribute Capacity (see Airspace/Ground Resource)
attribute Configuration (see Airspace/Ground Resource)
attribute Demand (see Airspace/Ground Resource)
attribute Load (see Airspace/Ground Resource)
attribute Location (see Airspace/Ground Resource)
attribute Name (see Airspace/Ground Resource)
attribute Saturation Threshold (see Airspace/Ground Resource)
attribute Separation Minima (see Airspace/Ground Resource)
attribute Usage Restrictions (see Airspace/Ground Resource)

services
The Airport Radar Services Area class performs the implicit services create, connect, and release. An Airport Radar Services Area object performs the implicit service access.

service Update Demand

Update the value of the Demand attribute to reflect the addition, change, or deletion of an instance connection.
service Update Load

Update the value of the Load attribute to reflect the addition, change, or deletion of an instance connection.

external input
None

external output
None

notes
None

specification Airport Traffic Area - unless otherwise specifically designated in FAR Part 91, that airspace within a horizontal radius of five statute miles from the geographical center of any airport in which a control tower is operating, extending from the surface up to, but not including, an altitude of 3,000 feet above the elevation of the airport. (AIM)

structure
specialization of Terminal Airspace Volume

instance connections
instance connection Airport Traffic Area (0, m) <-> Flight (0, m)
instance connection Airport Traffic Area (0, m) <-> Aircraft (0, m)
instance connection Airport Traffic Area (0, m) <-> Flight Manager (0, m)
instance connection Airport Traffic Area (0, m) <-> Air Traffic Manager (0, m)
instance connection Airport Traffic Area (0, m) <-> Traffic Manager (0, m)

message connection
Intrinsic only

object states
None

attributes
attribute Capacity (see Airspace/Ground Resource)
attribute Configuration (see Airspace/Ground Resource)
attribute Demand (see Airspace/Ground Resource)
attribute Load (see Airspace/Ground Resource)
attribute Location (see Airspace/Ground Resource)
attribute Name (see Airspace/Ground Resource)
attribute Saturation Threshold (see Airspace/Ground Resource)
attribute Separation Minima (see Airspace/Ground Resource)
attribute Usage Restrictions (see Airspace/Ground Resource)

services
The Airport Traffic Area class performs the implicit services create, connect, and release. An Airport Traffic Area object performs the implicit service access.

service Update Demand

Update the value of the Demand attribute to reflect the addition, change, or deletion of an instance connection.
service Update Load

Update the value of the Load attribute to reflect the addition, change, or deletion of an instance connection.

external input
None

external output
None

notes
None

specification Airspace/Ground Resource - the airspace and ground, used by flights and vehicles, over which the ATC system has control.

structure
contains parts Controlled Airspace; Airport Movement Area

instance connections
instance connection Airspace/Ground Resource (1) <-> Flight (0, m)
instance connection Airspace/Ground Resource (1) <-> Vehicle (0, m)
instance connection Airspace/Ground Resource (1) <-> Aircraft (0, m)
instance connection Airspace/Ground Resource (1) <-> Ground Vehicle (0, m)
instance connection Airspace/Ground Resource (1) <-> manager-type object (0, m)

message connection
Intrinsic only

object states
None

attributes
attribute Capacity - estimate of the number of flights or vehicles per unit time that can be accommodated by the resource (e.g., arrival capacity, departure capacity, sector capacity, fix capacity, airway capacity).

attribute Configuration - the relative placement of parts of the resource (e.g., which sectors make up an area) or the usage of the resource (e.g., an arrival sector vs. a departure sector, the subset of runways in use and whether each is used for arrivals or departures).

attribute Demand - estimate of the number of flights or vehicles per unit time that plan to use the resource (e.g., arrival demand, departure demand, sector demand, fix demand, airway demand).

attribute Load - actual utilization of a resource by aircraft or ground vehicles in a specific time period.

attribute Location - the physical location (e.g., lateral boundaries and altitude ranges) of the resource.

attribute Name - the ATC-assigned identification.

attribute Saturation Threshold - a demand or load value that should cause an alert.

attribute Separation Minima - the minimum longitudinal, lateral, or vertical distances by which aircraft are spaced through the application of ATC procedures. (AIM)

attribute Usage Restrictions - restrictions on the usage of a resource by flights or vehicles (e.g., an arrival rate of 40 between 1700 and 1800 UTC).

services
The Airspace/Ground Resource class performs the implicit services create, connect, and release. An Airspace/Ground Resource object performs the implicit service access.

service Update Demand

Update the value of the Demand attribute to reflect the addition, change, or deletion of an instance connection.
service Update Load

Update the value of the Load attribute to reflect the addition, change, or deletion of an instance connection.

external input
None

external output
None

notes
(1) Instance connections with Flight objects and Vehicle objects are related to the value of the Demand attribute; instance connections with Aircraft objects and Ground Vehicle objects are related to the value of the Load attribute. (2) The Demand attribute is not single-valued, but has values for each time period of interest. (3) The Location attribute is not necessarily single-valued (e.g., a sector may be defined by shelves). (4) The Separation Minima attribute is not necessarily single-valued (e.g., may have separation values for longitudinal, lateral, and vertical minima).

specification Airspace Surveillance System - a system for the tracking of airborne aircraft positions and the management of the information provided.

structure
specialization of Surveillance System

instance connection
Airspace Surveillance System (0, m) <-> Vehicle Surveillance System (0, m)

message connections
message Request Altitude Report, sent from Airspace Surveillance System
message Transmit & Receive Radar Pulse, sent from Airspace Surveillance System
message Transmit & Receive Radar Pulse, sent to Airspace Surveillance System

object states
None

attributes
attribute Area of Coverage (Inherited)
attribute Equipment Type (Inherited)
attribute Status (Inherited)

services
The Airspace Surveillance System class performs the implicit services create, connect, and release. An Airspace Surveillance System object performs the implicit service access.
service Locate, Identify & Report Flight

Locate each aircraft in the area of coverage, determine the identification of the flight of which the aircraft is a part, and report its identification and location.

external input
None

external output
None

notes
In reality, an airspace surveillance system might not be able to locate and identify all aircraft in its area of coverage, due in part to the lack of aircraft equipage and in part to capacity limitations of the surveillance system.

specification Airspace Volume - any volume of en route airspace.

structure
part of En Route Controlled Airspace
generalization of ACF Airspace; Sector; Protected Airspace Volume; Holding Pattern Airspace

instance connections
instance connection Airspace Volume (0, m) <-> Flight (0, m)
instance connection Airspace Volume (0, m) <-> Aircraft (0, m)
instance connection Airspace Volume (0, m) <-> Flight Manager (0, m)
instance connection Airspace Volume (0, m) <-> Air Traffic Manager (0, m)
instance connection Airspace Volume (0, m) <-> Traffic Manager (0, m)

message connection
Intrinsic only

object states
None

attributes
attribute Capacity (see Airspace/Ground Resource)
attribute Configuration (see Airspace/Ground Resource)
attribute Demand (see Airspace/Ground Resource)
attribute Load (see Airspace/Ground Resource)
attribute Location (see Airspace/Ground Resource)
attribute Name (see Airspace/Ground Resource)
attribute Saturation Threshold (see Airspace/Ground Resource)
attribute Separation Minima (see Airspace/Ground Resource)
attribute Usage Restrictions (see Airspace/Ground Resource)

services
The Airspace Volume class performs the implicit services create, connect, and release. An Airspace Volume object performs the implicit service access.

service Update Demand

Update the value of the Demand attribute to reflect the addition, change, or deletion of an instance connection.
service Update Load

Update the value of the Load attribute to reflect the addition, change, or deletion of an instance connection.

external input
None

external output
None

notes
(1) The Airspace Volume class was introduced to permit the inclusion of any arbitrarily-defined volume of airspace. (2) The list of specialization class is not exhaustive, but includes commonly-defined types of airspace.

specification Air Traffic - a grouping of flights determined by a defined criterion or set of criteria.

structure
specialization of Traffic
contains part Flight

instance connection
Air Traffic (0, m) <-> Air Traffic Manager (0, m)

message connection
None

object states
None

attribute
Selection Criteria (inherited from Traffic)
services
The Air Traffic class performs the implicit services create, connect, and release. An Air Traffic object performs the implicit service access.

service create

When requested by an Air Traffic Manager object, create an Air Traffic object with identified Flight objects as parts

external input
None
external output
None
notes
The definition of air traffic is unique to this model, although the term is sometimes used to mean either all airborne flights or some subset of flights defined by some understood but not rigorously-defined criterion (e.g., Chicago's traffic). The Federal Aviation Regulations define "air traffic" as "aircraft operating in the air or on an airport surface, exclusive of loading ramps and parking areas." The Air Traffic class exists in this model to allow the creation of well-defined groupings of flights for specific purposes (e.g., all flights above FL240 in Cleveland Center between 2100 and 2400 UTC, all flights outbound from Washington Center and inbound to JFK Airport on 19 March).

specification Air Traffic Manager - one who plans or supervises air traffic.

structure
specialization of Traffic Manager
instance connections
instance connection Air Traffic Manager (0, m) <-> Air Traffic (0, m)
instance connection Air Traffic Manager (0, m) <-> airspace-type resource (0, m)
instance connection Air Traffic Manager (0, m) <-> Interfacility Communications System (0, m)
instance connection Air Traffic Manager (0, m) <-> Intrafacility Communications System (0, m)
message connections
message Create Air Traffic object, sent to the Air Traffic class service "create"
message Request Usage Restrictions, sent from a Ground Traffic Manager object
message Request Usage Restrictions, sent to a Ground Traffic Manager object
message Request Usage Restrictions, sent from an Air Traffic Manager object
message Request Usage Restrictions, sent to an Air Traffic Manager object
message Provide Weather Forecast, sent to an Aviation Weather System Manager object
object states
None
attribute
Area of Responsibility (inherited)
services
The Air Traffic Manager class performs the implicit services create, connect, and release. An Air Traffic Manager object performs the implicit service access.
service Detect, Predict & Report Saturation

Determine whether saturation of an airspace-type resource is happening (based on the Load attribute) or is planned to happen (based on the Demand attribute) and notify the appropriate manager-type object.
service Determine Airspace Capacity

Determine the number of flights that can be accommodated by an airspace-type resource per unit time or instantaneously.
service Reserve Airspace

Coordinate with users that have special requirements for reserved blocks of airspace.
service Resolve Airspace Saturation Problem

Develop directives in response to present and predicted traffic flow problems.
service Set Airspace Saturation Threshold

Based upon the airspace-type resource capacity and other factors, determine a utilization value which, once predicted to be achieved or actually achieved, should cause an alert.

external input
None
external output
None
notes
(1) The Air Traffic Manager class does not represent a currently-staffed position; instead, it includes parts of the functionality of the Traffic Management Specialist, the Central Altitude Reservation Function Specialist, the Traffic Management Coordinator, and ATCT controllers. Other parts of the functionality of these positions are placed with other manager-type objects (e.g., some of the functionality of the local controller, an ATCT controller, is placed with the Flight Manager class, and some with the Vehicle Manager class). (2) The services of an Air Traffic Manager object might be performed either by humans or by automation.

specification Airway - a control area or portion thereof established in the form of a corridor, the centerline of which is defined by radio navigational aids (AIM)

structure
specialization of Route
contains parts (inherited) Fix/Waypoint; Route Segment
instance connections
instance connection Airway (0, m) <-> Flight (0, m)
instance connection Airway (0, m) <-> Aircraft (0, m)
instance connection Airway (0, m) <-> Flight Manager (0, m)
instance connection Airway (0, m) <-> Air Traffic Manager (0, m)
instance connection Airway (0, m) <-> Traffic Manager (0, m)
message connection
Intrinsic only
object states
None
attributes
attribute Capacity (Inherited)
attribute Configuration (Inherited)
attribute Demand (Inherited)
attribute Load (Inherited)
attribute Location (Inherited)
attribute Name (Inherited)
attribute Saturation Threshold (Inherited)
attribute Separation Minima (Inherited)
attribute Usage Restrictions (Inherited)
services
The Airway class performs the implicit services create, connect, and release. An Airway object performs the implicit service access.
service Update Demand

Update the value of the Demand attribute to reflect the addition, change, or deletion of an instance connection.
service Update Load

Update the value of the Load attribute to reflect the addition, change, or deletion of an instance connection.

external input
None
external output
None
notes
None

specification Area Route - a random area navigation route; a direct route, based on area navigation capabilities, between waypoints defined in terms of latitude/longitude coordinates, degree/distance fixes, or offsets from published or established routes/airways at a specified distance and direction. (adapted from AIM)

structure
specialization of Route
contains parts (inherited) Fix/Waypoint; Route Segment
instance connections
instance connection Area Route (0, m) <-> Flight (0, m)
instance connection Area Route (0, m) <-> Aircraft (0, m)
instance connection Area Route (0, m) <-> Flight Manager (0, m)
instance connection Area Route (0, m) <-> Air Traffic Manager (0, m)
instance connection Area Route (0, m) <-> Traffic Manager (0, m)
message connection
Intrinsic only
object states
None
attributes
attribute Capacity (Inherited)
attribute Configuration (Inherited)
attribute Demand (Inherited)
attribute Load (Inherited)
attribute Location (Inherited)
attribute Name (Inherited)
attribute Saturation Threshold (Inherited)
attribute Separation Minima (Inherited)
attribute Usage Restrictions (Inherited)
services
The Area Route class performs the implicit services create, connect, and release. An Area Route object performs the implicit service access.
service Update Demand

Update the value of the Demand attribute to reflect the addition, change, or deletion of an instance connection.
service Update Load

Update the value of the Load attribute to reflect the addition, change, or deletion of an instance connection.

external input
None
external output
None
notes
None

specification Arrival Clearance - the clearances issued to a flight, and not yet completely carried out, for the arrival phase of flight. The arrival clearance includes any standard or instrument approach procedure, as well as any altitude and vector assignments issued, or visual approach or contact approach approved, that must be followed in leaving the en route route until cleared to land on a runway. The model name "arrival clearance" is not to be confused with the ATC term "approach clearance." The approach clearance (authorization to conduct an instrument approach) is a subset of the arrival clearance.

structure
specialization of Clearance
part of Flight Clearance
instance connection
None
message connections
message Request Amend Clearance, sent from Pilot object
object states
None
attribute
Approach Procedure - the identification of a standard or special instrument approach procedure, visual or contact approach, vectors and altitude assignments that the aircraft must follow in leaving the en route route until cleared to land
services
The Arrival Clearance class performs the implicit services create, connect, and release. An Arrival Clearance object performs the implicit service access.
service Amend Clearance

Determine the affected attributes of the Arrival Clearance, and the needed change
Change the identified attributes to the new values

external input
None
external output
None
notes
The arrival clearance, for this model, does not include the clearance to land, because the clearance to land represents an allocation of a ground-type resource. The clearance to land is included as part of a ground clearance.

specification Aviation Weather Resource - the wind and weather products available to users of the ATC system (e.g., an area forecast, a surface aviation weather report) to assist in flight planning and the management of the basic wind/weather products in the creation of specialized products (e.g., a preflight weather briefing).

structure
specialization of Resource
contains parts Aviation Weather System
instance connection
None
message connections
None
object states
None
attribute
None
services
The Aviation Weather Resource class performs the implicit services create, connect, and release. An Aviation Weather Resource object performs the implicit service access.
external input
None
external output
None
notes
(1) The Aviation Weather Resource class exists only for convenience as the highest-level aviation weather resource. Aviation weather resource-type objects exists at a lower level in the aviation weather hierarchy. (2) The Aviation Weather Resource class refers only to the aviation weather functionality of the ATC system.

specification Aviation Weather System - a system of wind and weather products available to users of the ATC system and the management of those products in the creation of specialized products.

structure
contains parts Wind/Weather Product; Aviation Weather System Manager
instance connection
None
message connection
None
object states
None
attribute
Area of Coverage - the geographic area covered by reports.
services
The Aviation Weather System class performs the implicit services create, connect, and release. An Aviation Weather System object performs the implicit service access.
external input
None
external output
None
notes
None

specification Aviation Weather System Manager - a position (person or automation) that prepares standard wind and weather reports and creates specialized reports at the request of a manager-type object.

structure
part of Aviation Weather System
instance connection
None
message connections
message Request Special Report, from manager-type object
object states
None
attribute
None
services
The Aviation Weather System Manager class performs the implicit services create, connect, and release. An Aviation Weather System Manager object performs the implicit service access.
Create Specialized Report

Upon request by a manager-type object, create a specialized wind/weather report.

external input
The Aviation Weather System Manager is external to the ATC system.
external output
None
notes
An Aviation Weather System Manager object (e.g., a meteorologist) is not properly within the ATC model (i.e., is not an ATC manager), but is included for convenience.

specification Clearance - an authorization by ATC, for the purpose of preventing collisions between known aircraft, for an aircraft to proceed under specified traffic conditions within controlled airspace. (AIM)

structure
generalization of Flight Clearance; Ground Clearance; Departure Clearance; En Route Clearance; Arrival Clearance
instance connection
None
message connection
None
object states
None
attribute
None
services
service Amend Clearance

Determine the needed change to the clearance and carry it out

external input
None
external output
None
notes
The Clearance class was created as a convenience. In this model, the clearance associated with a flight or with a vehicle is the accumulation from the present time of all outstanding clearance instructions (those not yet carried out, and those in the process of being carried out).

specification Communications Resource - the communications media provided by the ATC system for the transfer of information between the ATC system and aircraft (e.g., the transfer of a clearance amendment by radio from a human specialist to an aircraft) and among ATC system components, and the management of the information.

structure
specialization of Resource
contains parts Communications System
instance connection
None
message connection
None
object states
None
attribute
None
services
The Communications Resource class performs the implicit services create, connect, and release. A Communications Resource object performs the implicit service access.
external input
None

external output
None
notes
(1) The Communications Resource class exists only for convenience as the highest-level communications resource. Communications resource-type objects exists at a lower level in the communications hierarchy. (2) The Communications Resource class refers only to the communications functionality of the ATC system.

specification Communications System - a system of communications media provided by the ATC system for the transfer of information between the ATC system and aircraft and among ATC system components, and the management of the information.

structure
part of Communications Resource
generalization of Interfacility Communications System; Intrafacility Communications System; Air/Ground Communications System
instance connection
Communications System (0, m) <-> Vehicle Communications System (0, m)
message connections
message Request Accept Message, to manager-type object
message Request Transmit Message, from manager-type object
message Request Transmit Message, from Vehicle Communications System object
message Request Transmit Message, to Vehicle Communications System object
object states
None
attributes
attribute Area of Coverage - the range of the communications equipment.
attribute Equipment Type - the type of communications equipment provided by the communications system.
attribute Status - operational or not operational.
services
The Communications System class performs the implicit services create, connect, and release. A Communications System object performs the implicit service access.
service connect

Upon determination that a vehicle is within the Area of Coverage of the Communications System object, create an instance connection between the Communications System object and the Vehicle Communications System object which is part of the Aircraft or Ground Vehicle object.
Upon determination that a vehicle is no longer within the Area of Coverage of the Communications System object, remove the instance connection between the Communications System object and the Vehicle Communications System object which is part of the Aircraft or Ground Vehicle object.
service Transmit Message

Upon request, transmit the provided message to the identified recipient.

external input
None
external output
None
notes
Instance connections and message connections exist almost exclusively for objects of specializations of communications system classes (not for objects of the Communications System class itself).

specification Controlled Airspace - airspace designated as a control zone, airport radar service area, terminal control area, transition area, control area, continental control area, and positive control area within which some or all aircraft may be subject to ATC. (AIM)

structure
part of Airspace/Ground Resource
contains parts Oceanic Controlled Airspace; En Route Controlled Airspace; Terminal Controlled Airspace
instance connections
instance connection Controlled Airspace (1) <-> Flight (0, m)
instance connection Controlled Airspace (1) <-> Aircraft (0, m)
instance connection Controlled Airspace (1) <-> Flight Manager (0, m)
instance connection Controlled Airspace (1) <-> Air Traffic Manager (0, m)
instance connection Controlled Airspace (1) <-> Traffic Manager (0, m)
message connection
Intrinsic only
object states
None
attributes
attribute Capacity (see Airspace/Ground Resource)
attribute Configuration (see Airspace/Ground Resource)
attribute Demand (see Airspace/Ground Resource)
attribute Load (see Airspace/Ground Resource)
attribute Location (see Airspace/Ground Resource)
attribute Name (see Airspace/Ground Resource)
attribute Saturation Threshold (see Airspace/Ground Resource)
attribute Separation Minima (see Airspace/Ground Resource)
attribute Usage Restrictions (see Airspace/Ground Resource)
services
The Controlled Airspace class performs the implicit services create, connect, and release. A Controlled Airspace object performs the implicit service access.
service Update Demand

Update the value of the Demand attribute to reflect the addition, change, or deletion of an instance connection.
service Update Load

Update the value of the Load attribute to reflect the addition, change, or deletion of an instance connection.

external input
None
external output
None
notes
None

specification Departure Clearance - the clearances issued to a flight, and not yet completely carried out, for the departure phase of flight. The departure clearance, also known as departure instructions, describes the route (e.g., standard instrument departure [SID] route), headings, or radar vectors that the aircraft must follow from the airport to the beginning of the route or to join the route in the en route clearance.

structure
specialization of Clearance
part of Flight Clearance
instance connection
None
message connections
message Request Amend Clearance, sent from a Pilot object
object states
None
attributes
attribute Departure Procedure - the route (e.g., SID), heading, or radar vectors that the aircraft must follow from the airport to the beginning of the route or to join the route in the en route clearance.
attribute Release Time - the earliest time the flight may depart. (AIM)
attribute Void Time - clearance void time - the specific time after which, if the flight has not departed, the clearance is void. (AIM)
services
The Departure Clearance class performs the implicit services create, connect, and release. A Departure Clearance object performs the implicit service access.
service Amend Clearance

Determine the affected attributes of the Departure Clearance, and the needed change.
Change the identified attributes to the new values.

external input
None
external output
None
notes
The departure clearance, for this model, includes the takeoff clearance, which represents an allocation of an airspace-type resource. The Release Time and Void Time attributes have values only when the flight originates at an airport not served by a control tower.

specification En Route Clearance - the clearances issued to a flight, and not yet completely carried out, for the en route phase of flight.

structure
specialization of Clearance
part of Flight Clearance
instance connection
None
message connections
message Request Amend Clearance, sent from a Pilot object
object states
None
attributes
attribute Altitude Profile - an altitude or sequence of altitudes assigned to the flight.
attribute Clearance Limit - the farthest point along the route to which the flight is cleared.
attribute Holding Instructions - special instructions to be followed when a holding pattern area is to be used; this atttribute has a value only when holding is required by ATC.
attribute Route - the route of flight approved for use by the flight; the approved route might terminate at a destination airport or at a clearance limit (which see).
attribute Speed Schedule - a speed or sequence of speeds assigned to a flight.
services
The En Route Clearance class performs the implicit services create, connect, and release. An En Route Clearance object performs the implicit service access.
service Amend Clearance

Determine the affected attributes of the En Route Clearance, and the needed change.
Change the values of the identified attributes to the new values.

external input
None
external output
None
notes
None

specification En Route Controlled Airspace - that part of controlled airspace used primarily for the en route phase of flights over land

structure
part of Controlled Airspace
contains parts Route; Airspace Volume
instance connections
instance connection En Route Controlled Airspace (1) <-> Flight (0, m)
instance connection En Route Controlled Airspace (1) <-> Aircraft (0, m)
instance connection En Route Controlled Airspace (1) <-> Flight Manager (0, m)
instance connection En Route Controlled Airspace (1) <-> Air Traffic Manager (0, m)
instance connection En Route Controlled Airspace (1) <-> Traffic Manager (0, m)
message connection
Intrinsic only
object states
None
attributes
attribute Capacity (see Airspace/Ground Resource)
attribute Configuration (see Airspace/Ground Resource)
attribute Demand (see Airspace/Ground Resource)
attribute Load (see Airspace/Ground Resource)
attribute Location (see Airspace/Ground Resource)
attribute Name (see Airspace/Ground Resource)
attribute Saturation Threshold (see Airspace/Ground Resource)
attribute Separation Minima (see Airspace/Ground Resource)
attribute Usage Restrictions (see Airspace/Ground Resource)
services
The En Route Controlled Airspace class performs the implicit services create, connect, and release. An En Route Controlled Airspace object performs the implicit service access.
service Update Demand

Update the value of the Demand attribute to reflect the addition, change, or deletion of an instance connection.
service Update Load

Update the value of the Load attribute to reflect the addition, change, or deletion of an instance connection.

external input
None
external output
None
notes
A Route object and an Airspace Volume object which are parts of the same En Route Controlled Airspace object might define parts of the same physical airspace, but both objects reflect common usage.

specification Fix/Waypoint - a fix or a waypoint. A fix is a geographical position determined by visual reference to the surface, by reference to one or more radio NAVAIDs, by celestial plotting, or by another navigational device. A waypoint is a predetermined geographical position used for route/instrument approach definition, or progress reporting purposes, that is defined relative to a VORTAC station or in terms of latitude/longitude coordinates. (AIM)

structure
part of Track; Oceanic Route; Route; Terminal Route
instance connections
instance connection Fix/Waypoint (0, m) <-> Flight (0, m)
instance connection Fix/Waypoint (0, m) <-> Aircraft (0, m)
instance connection Fix/Waypoint (0, m) <-> Flight Manager (0, m)
instance connection Fix/Waypoint (0, m) <-> Air Traffic Manager (0, m)
instance connection Fix/Waypoint (0, m) <-> Traffic Manager (0, m)
message connection
Intrinsic only
object states
None
attributes
attribute Capacity (see Airspace/Ground Resource)
attribute Configuration (see Airspace/Ground Resource)
attribute Demand (see Airspace/Ground Resource)
attribute Load (see Airspace/Ground Resource)
attribute Location (see Airspace/Ground Resource)
attribute Name (see Airspace/Ground Resource)
attribute Saturation Threshold (see Airspace/Ground Resource)
attribute Separation Minima (see Airspace/Ground Resource)
attribute Service Volume - for a NAVAID, the area of coverage
attribute Type - the type of fix or waypoint (e.g., VOR, latitude/longitude)
attribute Usage Restrictions (see Airspace/Ground Resource)
services
The Fix/Waypoint class performs the implicit services create, connect, and release. A Fix/Waypoint object performs the implicit service access.
service Update Demand

Update the value of the Demand attribute to reflect the addition, change, or deletion of an instance connection.
service Update Load

Update the value of the Load attribute to reflect the addition, change, or deletion of an instance connection.

external input
None
external output
None
notes
None

specification Flight - the operation of an aircraft on the surface or in the air; a flight can have three logical components, which are a flight plan, a flight clearance, and one or more aircraft.

structure
part of Air Traffic
contains parts Flight Clearance; Flight Plan; Aircraft
instance connections
instance connection Flight (0, m) <-> Flight Manager (0, 1)
instance connection Flight (0, m) <-> airspace-type (0, m)
instance connection Flight (0, m) <-> Flight (0, m)
message connections
None
object states
A Flight object has the following states: predeparture, departure, en route, arrival, and postarrival. The state changes are shown in figure 3-10. The following short description is copied from section 3.2.6.2 and applies to the usual flight; some details differ for particular flights (e.g., a VFR flight without a flight plan, a flight that files its flight plan after it is airborne). The predeparture state corresponds to that time before the aircraft makes use of the airport movement area of an airport; during this time period, the initial flight planning, including the receipt of weather briefings and the filing of the flight plan, is completed. The departure state corresponds to that time spent on the airport movement area for taxiing and takeoff and in the air until handed off to an en route controller. (There is no en route state for a tower en route flight.) The en route state lasts until the flight is given the arrival clearance for its destination airport. The arrival state lasts until the aircraft leaves the airport movement area of the destination airport. The postarrival state exists essentially to allow for flight plan closing (although an IFR flight plan is considered closed upon arrival at a controlled airport). The states of a flight are defined to correspond to the assignment of the manager rather than to the airspace/ground resource used (although this is a fine point, because the managers and the airspace/ground resources are also closely related). That is, a change in flight state is associated with a change in manager rather than with a change in resource usage.
attributes
attribute Trajectory - the planned four-dimensional path of the aircraft.
attribute Type - IFR or VFR or composite VFR/IFR.
services
The Flight class performs the implicit services create, connect, and release. A Flight object performs the implicit service access.
service Maintain Trajectory

Ensure that the prediction of the four-dimensional path of the aircraft is kept up-to-date.

external input
None
external output
None
notes
(1) For this model, a flight is synonymous with a flight segment: a departure by an aircraft after it has arrived at an airport is considered part of another flight. However, two or more Flight objects can be connected by instance connections to reflect a continuing flight. (2) When an aircraft is on the ground, it can be part of a flight and part of a vehicle. (3) During the predeparture state of a Flight object, an instance connection exists first between the Flight object and the Flight Manager object (e.g., a Flight Service Station preflight briefing specialist) with which initial flight planning is carried out. After the initial flight planning, and before the aircraft has received any flight clearance, an instance connection exists between the Flight object and the first Flight Manager object that can deliver any part of the departure or en route clearance (e.g., the clearance delivery position). After this point, the instance connection is established and broken as the aircraft is "handed off" from one flight manager (e.g., controller) to another. Finally, after the arrival state of the Flight object, an instance connection exists between the Flight object and the Flight Manager object that can assist in closing the flight plan (note that this flight manager could be another FSS specialist for a VFR flight or the local controller for an IFR flight, using the Flight Manager object's service Assist in Flight Planning). (4) Instance connections between a Flight object and an airspace/ground resource-type object exist based upon the planned use of the resource by the flight as reflected in the flight plan. Each instance connection is created when the flight plan is created, changed as the flight plan is changed, and deleted once the resource has been used by the flight. Each Flight object having an instance connection with a resource-type object contributes to the value of the Demand attribute of that resource.

specification Flight Clearance - the aggregate of the clearances issued to a flight, and not yet completely carried out, for the departure, en route, and arrival phases of flight; a class created for convenience, without a direct analogue in the ATC system

structure
specialization of Clearance
part of Flight
contains parts Departure Clearance; En Route Clearance; Approach Clearance
instance connection
None
message connections
None
object states
None
attribute
Flight Identification - an ATC-approved identification; could have the same value as the Aircraft Identification attribute of an Aircraft object which is part of the Flight object.
services
The Flight Clearance class performs the implicit services create, connect, and release. A Flight Clearance object performs the implicit service access.
external input
None
external output
None
notes
None

specification Flight Manager - one who plans or supervises flights, including approving resource usage by individual flights.

structure
specialization of Manager
instance connections
instance connection Flight Manager (0, 1) <-> Flight (0, m)
instance connection Flight Manager (0, m) <-> airspace-type resource (0, m)
instance connection Flight Manager (0, m) <-> Air/Ground Communications System (0, m)
instance connection Flight Manager (0, m) <-> Interfacility Communications System (0, m)
instance connection Flight Manager (0, m) <-> Intrafacility Communications System (0, m)
message connections
message Request Accept Control Responsibility, sent from Flight Manager object
message Request Accept Control Responsibility, sent to Flight Manager object
message Request Adherence to Clearance, sent to Pilot object
message Request Aircraft Altitude, sent to Pilot object
message Request Aircraft Identification, sent to Pilot object
message Request Aircraft Position, sent to Pilot object
message Request Amend Flight Plan & Clearance, sent to Pilot object
message Request Flight Plan Amendment, sent from Pilot object
message Request IFR Flight Separation, sent from Flight Manager object
message Request IFR Flight Separation, sent to Flight Manager object
message Request Preflight Briefing, sent from Pilot object
message Request Resource, sent from Flight Manager object
message Request Resource, sent to Flight Manager object
message Request Transfer of Communications, sent to Pilot object
object states
None
attribute
Area of Responsibility (Inherited)
services
The Flight Manager class performs the implicit services create, connect, and release. A Flight Manager object performs the implicit service access.
service Asssist in Flight Planning

Upon request, provide or update preflight briefing.
Upon request, evaluate and accept flight plan.
Upon request, evaluate and accept flight plan modifications.
Open flight plan (automatically, or upon request).
Close flight plan (automatically, or upon request).
service Assist in Weather Avoidance

Collect (solicit and receive) weather reports from pilots.
Upon request, provide weather advisories.
service Detect, Predict & Report Restriction Violation

Determine whether a violation of a usage restriction for an airspace-type resource is happening or is planned to happen and notify the appropriate manager-type object.
service Detect, Predict & Report Separation Violation

Determine whether a violation of separation minima (i.e., an aircraft-to-aircraft conflict or an aircraft-to-airspace conflict) is happening or is planned to happen and notify the appropriate manager-type object.
service Direct Transfer of Communications

Inform a flight (pilot) of the frequency that should be used in future communications.
service Ensure Restriction Compliance

When requested by a flight to use an airspace-type resource, determine whether a usage restriction exists for the resource and approve or disapprove the use of the resource, as appropriate.
When it is discovered that a flight has planned to use an airspace-type resource contrary to usage restrictions, determine whether and how to change the resource usage of that flight.
service Generate & Deliver Clearance

Translate instructions to a flight into clearance language and deliver via a communications medium.
service Separate IFR Flights

When requested by a flight to change its flight plan, determine whether a problem (i.e., an aircraft-to-aircraft conflict or an aircraft-to-airspace conflict) would exist based upon the revised plan and approve or disapprove the plan, as appropriate.
When it is discovered that following an existing flight plan would cause a problem, determine whether and how to change the plan.
service Transfer & Accept Control Responsibility

When controlling a flight: determine the next appropriate flight manager and time of control transfer and offer control to that flight manager.
When offered control of a flight: evaluate the appropriateness of receiving control of the flight and either accept or deny control transfer.

external input
None
external output
None
notes
(1) The Flight Manager class does not represent a currently-staffed position; instead, it includes parts of the functionality of several ATC positions. (2) The services of a Flight Manager object might be performed either by humans or by automation, or shared.

specification Flight Plan - Specified information relating to the intended flight of an aircraft that is filed orally or in writing with an FSS or an ATC facility, as amended.

structure
part of Flight
instance connections
None
message connections
message Amend Flight Plan, sent from Pilot object
object states
An IFR Flight Plan object has two states, open and closed (also called active and inactive). A flight plan is closed when the aircraft is on the ground before takeoff. An IFR flight plan is opened after takeoff as soon as the aircraft is detected by radar, or (in a nonradar environment) as soon as the aircraft reports entering controlled airspace. A VFR flight plan is activated as soon as the aircraft is airborne and has informed the Flight Service Station of the actual time of departure. An IFR flight plan is closed when the aircraft lands at an airport with a control tower, or (when there is no control tower) the aircraft notifies ATC or the Flight Service Station of the landing, or when the flight cancels its IFR flight plan. A VFR flight plan is closed when the aircraft so notifies the destination Flight Service Station. When a VFR flight plan is not activated within one hour of the proposed departure time, it is cancelled.
attributes
As required for FAA Form 7233-1 (Flight Plan). The values of the attributes reflect all amendments since flight plan filing.
services
The Flight Plan class performs the implicit services create, connect, and release. A Flight Plan object performs the implicit service access.
service Amend Flight Plan

Determine the affected attributes of the Flight Plan, and the needed change
Change the identified attributes to the new values

external input
Airline Dispatch Offices; Military Base Operations; DUAT
external output
Airline Dispatch Offices; Military Base Operations; DUAT
notes
The Flight Plan class represents the flight plan commonly known in ATC, as amended throughout the flight.

specification Ground Clearance - the aggregate of the clearances issued to a ground vehicle, and not yet completely carried out, for movement on the airport movement area; a class created for convenience, without a direct analogue in the ATC system movement area

structure
specialization of Clearance
part of Vehicle
instance connection
None
message connections
message Request Amend Ground Clearance, sent from the Ground Vehicle Operator object
object states
None
attributse
attribute Ground Vehicle Identification - an ATC-approved identification of the Ground Vehicle object of which the Ground Clearance object is a part; could have the same value as the Ground Vehicle Identification attribute of the Ground Vehicle object which is also part of the Vehicle object.
attribute Route - the route approved for use in traversing the airport movement area.
services
The Ground Clearance class performs the implicit services create, connect, and release. A Ground Clearance object performs the implicit service access.
service Amend Clearance

Determine the needed change to the Route attribute and carry out the change

external input
None
external output
None
notes
None

specification Ground Surveillance System - a system for the tracking of aircraft and ground vehicle positions on an airport movement area and the management of the information provided.

structure
specialization of Surveillance System
instance connection
Ground Surveillance System (0, m) <-> Vehicle Surveillance System (0, m)
message connections
message Transmit & Receive Radar Pulse, sent from Ground Surveillance System
message Transmit & Receive Radar Pulse, sent to Ground Surveillance System
object states
None
attributes
attribute Area of Coverage (Inherited)
attribute Equipment Type (Inherited)
attribute Status (Inherited)
services
The Ground Surveillance System class performs the implicit services create, connect, and release. A Ground Surveillance System object performs the implicit service access.
service Locate, Identify & Report Vehicle

Locate each aircraft and ground vehicle in the area of coverage, determine its identification, and report its identification and location.

external input
None
external output
None
notes
In reality, a ground surveillance system might not be able to locate and identify all aircraft or ground vehicles in its area of coverage, due in part to interference from other objects and in part to capacity limitations of the surveillance system.

specification Ground Traffic - a grouping of vehicles determined by a defined criterion or set of criteria.

structure
specialization of Traffic
contains part Vehicle
instance connection
Ground Traffic <-> Ground Traffic Manager (0, m)
message connection
None
object states
None
attribute
Selection Criteria (inherited from Traffic)
services
The Ground Traffic class performs the implicit services create, connect, and release. A Ground Traffic object performs the implicit service access.
service connect

When requested by a Ground Traffic Manager object, create an object with identified Vehicle objects as parts

external input
None
external output
None
notes
The definition of ground traffic is unique to this model. The Ground Traffic class exists in this model to allow the creation of well-defined groupings of vehicles for specific purposes (e.g., all vehicles needing to cross runway 14 to get to runway 9 in the next half hour).

specification Ground Traffic Manager - one who plans or supervises ground traffic.

structure
specialization of Traffic Manager
instance connections
instance connection Ground Traffic Manager (1) <-> Ground Traffic (0, m)
instance connection Ground Traffic Manager (0, m) <-> ground-type resource (0, m)
instance connection Ground Traffic Manager (0, m) <-> Air/Ground Communications System (0, m)
instance connection Ground Traffic Manager (0, m) <-> Interfacility Communications System (0, m)
instance connection Ground Traffic Manager (0, m) <-> Intrafacility Communications System (0, m)
message connections
message Create Ground Traffic Object, sent to Ground Traffic class service "create"
message Request Usage Restrictions, sent from Air Traffic Manager object
message Request Usage Restrictions, sent from Ground Traffic Manager object
message Request Usage Restrictions, sent to Air Traffic Manager object
message Request Usage Restrictions, sent to Ground Traffic Manager object
object states
None
attribute
Area of Responsibility (inherited)
services
The Ground Traffic Manager class performs the implicit services create, connect, and release. A Ground Traffic Manager object performs the implicit service access.
service Detect, Predict & Report Saturation

Determine whether saturation of a ground-type resource is happening (based on the Load attribute) or is planned to happen (based on the Demand attribute) and notify the appropriate manager-type object.
service Determine Ground Capacity

Determine the number of vehicles that can be accommodated by an ground resource-type resource per unit time or instantaneously.
service Resolve Ground Saturation Problem

Develop directives in response to present and predicted vehicle flow problems.
service Set Ground Saturation Threshold

Based upon the ground resource-type capacity and other factors, determine a utilization value which, once achieved, should cause an alert.

external input
None
external output
None
notes
(1) The Ground Traffic Manager class does not represent a currently-staffed position; instead, it includes parts of the functionality of positions such as the ATCT positions that determine ground capacity. (2) The services of a Ground Traffic Manager object might be performed either by humans or by automation.

specification Ground Vehicle - a vehicle, other than an aircraft, that traverses a part of the airport movement area in the performance of its duties (e.g., snow removal vehicle)

structure
part of Vehicle
contains parts Ground Vehicle Operator; Vehicle Surveillance System; Vehicle Navigation System; Vehicle Communications System
instance connection
None
message connection
Create Vehicle Object, sent to Vehicle class
object states
A Ground Vehicle object has two states, "active" and "inactive," depending on whether the ground vehicle is on or off of the airport movement area, respectively.
attributes
attribute Ground Vehicle Identification - an ATC-approved identification; might be the radio call sign.
attribute Location - the position of the ground vehicle as known by ATC, whether determined by ATC or reported to ATC by the ground vehicle itself and recorded by ATC. Location includes lateral dimension and time.
services
The Ground Vehicle class performs the implicit services create, connect, and release. A Ground Vehicle object performs the implicit service access.
service create

Create and initialize, as specified for the implicit service create.
When a Ground Vehicle object is created and there does not already exist a Vehicle object of which the Ground Vehicle object is to be a part, requests the Vehicle class to create a Vehicle object of which the Ground Vehicle object is a part.

external input
None
external output
None
notes
Instance connections occur higher (i.e., between a Vehicle object and another object ) and lower (i.e., between a part object and another object) than a Ground Vehicle object in the structure.

specification Ground Vehicle Operator - the operator of a ground vehicle; the pilot when an aircraft is still on the ground

structure
part of Ground Vehicle
instance connection
None
message connection
message Message Available, from a Vehicle Communications System object that is part of the same Ground Vehicle object as the Ground Vehicle Operator object
message Perform Navigation, to the Vehicle Navigation System object
message Request Adherence to Clearance, from a Vehicle Manager object
message Request Amend Clearance, to the Ground Clearance object which is part of the Vehicle object
message Request Amend Ground Vehicle Route, to the Ground Vehicle Route object which is part of the Vehicle object
message Request Amend Ground Vehicle Route & Ground Clearance, from a Vehicle Manager object
message Request Create Ground Vehicle Object, to the Ground Vehicle class
message Request Ground Vehicle Route Amendment, to a Vehicle Manager object
message Request Report Ground Vehicle Position, from a Vehicle Manager object
message Request Transfer of Communications, from a Vehicle Manager object
message Request Vehicle Position, sent to the Vehicle Navigation System object which is part of the same Ground Vehicle object as the Ground Vehicle Operator object
message Send Message, to a Vehicle Communications System object that is part of the same Ground Vehicle object as the Ground Vehicle Operator object
message Send Vehicle Identification, sent to the Vehicle Surveillance System object which is part of the same Ground Vehicle object as the Ground Vehicle Operator object
message Set Frequency, sent to the Vehicle Communications System object which is part of the same Ground Vehicle object as the Ground Vehicle Operator object
object states
None
attribute
Position - the driver or pilot
services
The Ground Vehicle Operator class performs the implicit services create, connect, and release. A Ground Vehicle Operator object performs the implicit service access.
service create

Create and initialize, as specified for the implicit service create.
When a Ground Vehicle Operator object is created and there does not already exist an Ground Vehicle object of which the Ground Vehicle Operator object is to be a part, requests the Ground Vehicle class to create an Ground Vehicle object of which the Ground Vehicle Operator object is a part.
service Avoid Other Ground Traffic

Ensure that other ground traffic is avoided, whether based on personal observation or the direction of a vehicle manager.
service Execute Movement

Perform the duties necessary to carry out the movement on the airport movement area, including (for example)

Ensuring that the aircraft or ground vehicle follows the planned ground plan.
Ensuring that clearances and instructions are carried out.

service Manage Equipment

Perform the duties necessary to ensure the proper performance of the Vehicle Surveillance System object, the Vehicle Navigation System object, and the Vehicle Communications System object.
service Report Ground Vehicle Position

When requested by a Vehicle Manager object, request a Vehicle Navigation System object which is part of the same Ground Vehicle object to determine the location of the ground vehicle.
service Request Movement

Coordinate movement on the airport movement area with a vehicle manager.

external input
None
external output
None
notes
(1) The (non-implicit) services of a Ground Vehicle Operator object are performed by a human. (2) The service Manage Equipment is performed, for the most part, independently of other objects, but also responds to external requests , e.g., a manager-type object requesting a particular beacon code setting for the transponder. (3) The service Report Ground Vehicle Position gets information from the Vehicle Navigation System object, not the Vehicle Surveillance System object, which responds independently to ATC's Surveillance System object.

specification Ground Vehicle Route - the planned route of movement for the ground vehicle across the airport movement area.

structure
part of Vehicle
instance connection
None
message connection
message Request Amend Ground Vehicle Route, sent from Ground Vehicle Operator object
object states
A Ground Vehicle Route has two states, active and inactive, depending on whether the ground vehicle location is on or off of the airport movement area, respectively. Once the ground vehicle has exited the airport movement area and has completed the planned route, the object can be deleted.
attribute
Ground Route - the planned route on the airport movement area.
services
The Ground Vehicle Route class performs the implicit services create, connect, and release. A Ground Vehicle Route object performs the implicit service access.
service Amend Ground Vehicle Route

Determine the needed change to the Ground Route attribute and carry out the change.

external input
None
external output
None
notes
None

specification Holding Area - an area on the airport movement area, other than a taxiway or runway, where an aircraft might wait for further instructions.

structure
part of Airport Movement Area
instance connections
instance connection Holding Area (0, m) <-> Vehicle (0, m)
instance connection Holding Area (0, m) <-> Aircraft (0, m)
instance connection Holding Area (0, m) <-> Vehicle Manager (0, m)
instance connection Holding Area (0, m) <-> Ground Traffic Manager (0, m)
instance connection Holding Area (0, m) <-> Traffic Manager (0, m)
object states
None
attributes
attribute Capacity (see Airspace/Ground Resource)
attribute Configuration (see Airspace/Ground Resource)
attribute Demand (see Airspace/Ground Resource)
attribute Load (see Airspace/Ground Resource)
attribute Location (see Airspace/Ground Resource)
attribute Name (see Airspace/Ground Resource)
attribute Saturation Threshold (see Airspace/Ground Resource)
attribute Separation Minima (see Airspace/Ground Resource)
attribute Status - active or inactive.
attribute Surface Condition - the condition of the holding area surface (e.g., covered with ice, snow, or long grass).
attribute Usage Restrictions (see Airspace/Ground Resource)
services
The Holding Area class performs the implicit services create, connect, and release. A Holding Area object performs the implicit service access.
service Update Demand

Update the value of the Demand attribute to reflect the addition, change, or deletion of an instance connection.
service Update Load

Update the value of the Load attribute to reflect the addition, change, or deletion of an instance connection.

external input
None
external output
None
notes
None

specification Holding Pattern Airspace - the airspace containing a holding pattern.

structure
specialization of Airspace Volume
instance connections
instance connection Holding Pattern Airspace (0, m) <-> Flight (0, m)
instance connection Holding Pattern Airspace (0, m) <-> Aircraft (0, m)
instance connection Holding Pattern Airspace (0, m) <-> Flight Manager (0, m)
instance connection Holding Pattern Airspace (0, m) <-> Air Traffic Manager (0, m)
instance connection Holding Pattern Airspace (0, m) <-> Traffic Manager (0, m)
message connection
Intrinsic only
object states
None
attributes
attribute Capacity (see Airspace/Ground Resource)
attribute Configuration (see Airspace/Ground Resource)
attribute Demand (see Airspace/Ground Resource)
attribute Load (see Airspace/Ground Resource)
attribute Location (see Airspace/Ground Resource)
attribute Name (see Airspace/Ground Resource)
attribute Saturation Threshold (see Airspace/Ground Resource)
attribute Separation Minima (see Airspace/Ground Resource)
attribute Usage Restrictions (see Airspace/Ground Resource)
services
The Holding Pattern Airspace class performs the implicit services create, connect, and release. A Holding Pattern Airspace object performs the implicit service access.
service Update Demand

Update the value of the Demand attribute to reflect the addition, change, or deletion of an instance connection.
service Update Load

Update the value of the Load attribute to reflect the addition, change, or deletion of an instance connection.

external input
None
external output
None
notes
None

specification Interfacility Communications System - a system of communications media provided by the ATC system for the transfer of information among ATC specialists in different facilities and the management of the information.

structure
specialization of Communications System
instance connection
Interfacility Communications System (0, m) <-> manager-type object (0, m)
message connections
message Request Transmit Message, from manager-type object
message Request Accept Message, to manager-type object
object states
None
attributes
attribute Area of Coverage (Inherited)
attribute Equipment Type (Inherited)
attribute Status (Inherited)
services
The Interfacility Communications System class performs the implicit services create, connect, and release. An Interfacility Communications System object performs the implicit service access.
serviceconnect (Inherited)
service Transmit Message (Inherited)
external input
None
external output
None
notes
None

specification Intrafacility Communications System - a system of communications media provided by the ATC system for the transfer of information among ATC specialists in the same facility and the management of the information.

structure
specialization of Communications System
instance connection
Intrafacility Communications System (0, m) <-> manager-type object (0, m)
message connections
message Request Accept Message, to manager-type object
message Request Transmit Message, from manager-type object
object states
None
attributes
attribute Area of Coverage (Inherited)
attribute Equipment Type (Inherited)
attribute Status (Inherited)
services
The Intrafacility Communications System class performs the implicit services create, connect, and release. An Intrafacility Communications System object performs the implicit service access.
service connect (Inherited)
service Transmit Message (Inherited)
external input
None
external output
None
notes
None

specification Jet Route -- a route designed to serve aircraft operations from 18,000 feet MSL up to and including flight level 450. The routes are referred to as "J" routes with numbering to identify the designated route; e.g., J105. (AIM)

structure
specialization of Route
contains parts (inherited) Fix/Waypoint; Route Segment
instance connections
instance connection Jet Route (0, m) <-> Flight (0, m)
instance connection Jet Route (0, m) <-> Aircraft (0, m)
instance connection Jet Route (0, m) <-> Flight Manager (0, m)
instance connection Jet Route (0, m) <-> Air Traffic Manager (0, m)
instance connection Jet Route (0, m) <-> Traffic Manager (0, m)
message connection
Intrinsic only
object states
None
attributes
attribute Capacity (Inherited)
attribute Configuration (Inherited)
attribute Demand (Inherited)
attribute Load (Inherited)
attribute Location (Inherited)
attribute Name (Inherited)
attribute Saturation Threshold (Inherited)
attribute Separation Minima (Inherited)
attribute Usage Restrictions (Inherited)
services
The Jet Route class performs the implicit services create, connect, and release. A Jet Route object performs the implicit service access.
service Update Demand

Update the value of the Demand attribute to reflect the addition, change, or deletion of an instance connection.
service Update Load

Update the value of the Load attribute to reflect the addition, change, or deletion of an instance connection.

external input
None
external output
None
notes
None

specification Landing Navigation System- a system of navigation aids to assist aircraft in approach navigation and the management of the information provided.

structure
specialization of Navigation System
instance connection
Landing Navigation System (0, m) <-> Vehicle Navigation System (0, m)
message connections
message Offer Altitude Information, to Vehicle Navigation System
message Offer Azimuth Information, to Vehicle Navigation System
message Request Distance Information, from Vehicle Navigation System
object states
None
attributes
attribute Identifier Code (Inherited)
attribute Frequency Channels (Inherited)
attribute Location (Inherited)
attribute NAVAID Type (Inherited)
attribute Area of Coverage (Inherited)
attribute Status (Inherited)
services
The Landing Navigation System class performs the implicit services create, connect, and release. A Landing Navigation System object performs the implicit service access.
service connect (Inherited)
service Transmit Azimuth Information (Inherited)
service Transmit Elevation Information

As scheduled, transmit information with which a receiving aircraft can determine its elevation during an approach
service Transmit NAVAID Identifier (Inherited)
service Transmit Range Information (Inherited)
external input
None
external output
None
notes
The services Transmit Range Information, Transmit Azimuth Information, and Transmit Elevation Information may not be possible for some landing navigation systems; some specializations of landing navigation systems can provide additional services.

specification Manager - one who handles or directs with a degree of skill; one who alters by manipulation; a supervisor, executor, or administrator.

structure
generalization of Traffic Manager; Flight Manager; Vehicle Manager
instance connection
None
message connection
None
object states
None
attribute
Area of Responsibility - the users or resources over which the manager has management responsibilities

services
None
external input
None
external output
None
notes
The Manager class exists as a convenience; any object in the manager hierarchy is usually an object of a class lower in the user hierarchy than the Manager class.

specification Military Training Route - airspace of defined vertical and lateral dimensions established for the conduct of military flights training at airspeeds in excess of 250 knots IAS. (AIM)

structure
specialization of Route

contains parts (inherited) Fix/Waypoint; Route Segment
instance connections
instance connection Military Training Route (0, m) <-> Flight (0, m)
instance connection Military Training Route (0, m) <-> Aircraft (0, m)
instance connection Military Training Route (0, m) <-> Flight Manager (0, m)
instance connection Military Training Route (0, m) <-> Air Traffic Manager (0, m)
instance connection Military Training Route (0, m) <-> Traffic Manager (0, m)
message connection
Intrinsic only
object states
None
attributes
attribute Capacity (Inherited)
attribute Configuration (Inherited)
attribute Demand (Inherited)
attribute Load (Inherited)
attribute Location (Inherited)
attribute Name (Inherited)
attribute Saturation Threshold (Inherited)
attribute Separation Minima (Inherited)
attribute Usage Restrictions (Inherited)
services
The Military Training Route class performs the implicit services create, connect, and release. A Military Training Route object performs the implicit service access.
service Update Demand

Update the value of the Demand attribute to reflect the addition, change, or deletion of an instance connection.
service Update Load

Update the value of the Load attribute to reflect the addition, change, or deletion of an instance connection.

external input
None
external output
None
notes
None

specification Navigation Resource - navigation aids provided by the ATC system to assist aircraft in navigating between points and the management of the information provided (e.g., the broadcasting of a NAVAID position by radio signal).

structure
specialization of Resource
contains parts Navigation System
instance connection
None
message connection
None
object states
None
attribute
None
services
The Navigation Resource class performs the implicit services create, connect, and release. A Navigation Resource object performs the implicit service access.
external input
None
external output
None

notes
(1) The Navigation Resource class exists only for convenience as the highest-level navigation resource. Navigation resource-type objects typically exist at a lower level in the navigation hierarchy. (2) The Navigation Resource class refers only to the navigation functionality of the ATC system, i.e., only those navigation systems certified by the Federal Aviation Administration to be primary navigation systems.

specification Navigation System - a system of navigation aids to assist aircraft in navigating between points and the management of the information provided.

structure
part of Navigation Resource
generalization of Landing Navigation System
instance connection
Navigation System (0, m) <-> Vehicle Navigation System (0, m)
message connections
message Request Distance Information, from Vehicle Navigation System
message Offer Azimuth Information, to Vehicle Navigation System
object states
None
attributes
attribute Area of Coverage - the range of the navigation equipment
attribute Frequency Channels - the frequencies used by the NAVAID to send and to receive signals (e.g., a four or five digit frequency for a VOR station)
attribute Identifier Code - the identification of the ground station associated with the navigation system (e.g., a three-letter identifier for a VOR station)
attribute Location - the geographical position of the ground station associated with the navigation system
attribute NAVAID Type - the type of navigation aid provided by the navigation system (e.g., VOR, VOR/DME, LORAN-C)
attribute Status - operational, not operational, or test
services
The Navigation System class performs the implicit services create, connect, and release. A Navigation System object performs the implicit service access.
service connect

Upon determination that an aircraft is within the Area of Coverage of the Navigation System object, create an instance connection between the Navigation System object and the Vehicle Navigation System object which is part of the Aircraft or Ground Vehicle object.
Upon determination that an aircraft is no longer within the Area of Coverage of the Navigation System object, remove the instance connection between the Navigation System object and the Vehicle Navigation System object which is part of the Aircraft object.
service Transmit Azimuth Information

As scheduled, transmit information with which a receiving aircraft can determine the direction of the NAVAID from the aircraft
service Transmit NAVAID Identifier

Continuously transmit the identifier code on the assigned frequency
service Transmit Range Information

As scheduled, transmit information with which a receiving aircraft can determine the distance from the aircraft to the NAVAID

external input
None
external output
None
notes
The services Transmit Range Information and Transmit Azimuth Information might not be possible for some navigation systems; some specializations of navigation systems can provide additional services.

specification Oceanic Airway - a control area or portion thereof established in the form of a corridor in oceanic airspace, the centerline of which is defined by radio navigational aids or in terms of latitude/longitude coordinates.

structure
part of Oceanic Controlled Airspace
generalization of Track; Oceanic Route
instance connections
instance connection Oceanic Airway (0, m) <-> Flight (0, m)
instance connection Oceanic Airway (0, m) <-> Aircraft (0, m)
instance connection Oceanic Airway (0, m) <-> Flight Manager (0, m)
instance connection Oceanic Airway (0, m) <-> Air Traffic Manager (0, m)
instance connection Oceanic Airway (0, m) <-> Traffic Manager (0, m)
message connection
Intrinsic only
object states
None
attributes
attribute Capacity (see Airspace/Ground Resource)
attribute Configuration (see Airspace/Ground Resource)
attribute Demand (see Airspace/Ground Resource)
attribute Load (see Airspace/Ground Resource)
attribute Location (see Airspace/Ground Resource)
attribute Name (see Airspace/Ground Resource)
attribute Primary Direction - the expected direction of flight (e.g., east or west)
attribute Saturation Threshold (see Airspace/Ground Resource)
attribute Separation Minima (see Airspace/Ground Resource)
attribute Time Period - the time during which the oceanic airway is in effect as defined
attribute Usage Restrictions (see Airspace/Ground Resource)
services
The Oceanic Airway class performs the implicit services create, connect, and release. An Oceanic Airway object performs the implicit service access.
service Update Demand

Update the value of the Demand attribute to reflect the addition, change, or deletion of an instance connection.
service Update Load

Update the value of the Load attribute to reflect the addition, change, or deletion of an instance connection.

external input
None
external output
None
notes
None

specification Oceanic Controlled Airspace - that part of controlled airspace used primarily for the en route phase of flights over (a large body of) water, such as over an ocean.

structure
part of Controlled Airspace
contains parts Oceanic Airway
instance connections
instance connection Oceanic Controlled Airspace (0, m) <-> Flight (0, m)
instance connection Oceanic Controlled Airspace (0, m) <-> Aircraft (0, m)
instance connection Oceanic Controlled Airspace (0, m) <-> Flight Manager (0, m)
instance connection Oceanic Controlled Airspace (0, m) <-> Air Traffic Manager (0, m)
instance connection Oceanic Controlled Airspace (0, m) <-> Traffic Manager (0, m)
message connection
Intrinsic only
object states
None
attributes
attribute Capacity (see Airspace/Ground Resource)
attribute Configuration (see Airspace/Ground Resource)
attribute Demand (see Airspace/Ground Resource)
attribute Load (see Airspace/Ground Resource)
attribute Location (see Airspace/Ground Resource)
attribute Name (see Airspace/Ground Resource)
attribute Saturation Threshold (see Airspace/Ground Resource)
attribute Separation Minima (see Airspace/Ground Resource)
attribute Usage Restrictions (see Airspace/Ground Resource)
services
The Oceanic Controlled Airspace class performs the implicit services create, connect, and release. An Oceanic Controlled Airspace object performs the implicit service access.
service Update Demand

Update the value of the Demand attribute to reflect the addition, change, or deletion of an instance connection.
service Update Load

Update the value of the Load attribute to reflect the addition, change, or deletion of an instance connection.

external input
None
external output
None
notes
None

specification Oceanic Route - a low-altitude one-way oceanic airway defined by NAVAIDs.

structure
specialization of Oceanic Airway
contains parts Fix/Waypoint; Route Segment
instance connections
instance connection Oceanic Route (0, m) <-> Flight (0, m)
instance connection Oceanic Route (0, m) <-> Aircraft (0, m)
instance connection Oceanic Route (0, m) <-> Flight Manager (0, m)
instance connection Oceanic Route (0, m) <-> Air Traffic Manager (0, m)
instance connection Oceanic Route (0, m) <-> Traffic Manager (0, m)
message connection
Intrinsic only
object states
None
attributes
attribute Capacity (see Airspace/Ground Resource)
attribute Configuration (see Airspace/Ground Resource)
attribute Demand (see Airspace/Ground Resource)
attribute Load (see Airspace/Ground Resource)
attribute Location (see Airspace/Ground Resource)
attribute Name (see Airspace/Ground Resource)
attribute Primary Direction (Inherited)
attribute Saturation Threshold (see Airspace/Ground Resource)
attribute Separation Minima (see Airspace/Ground Resource)
attribute Time Period (Inherited)
attribute Usage Restrictions (see Airspace/Ground Resource)
services
The Oceanic Route class performs the implicit services create, connect, and release. An Oceanic Route object performs the implicit service access.
service Update Demand

Update the value of the Demand attribute to reflect the addition, change, or deletion of an instance connection.
service Update Load

Update the value of the Load attribute to reflect the addition, change, or deletion of an instance connection.

external input
None
external output
None
notes
None

specification PAR - Preferential Arrival Route; a specific arrival route from an appropriate en route point to an airport or arrival area. It may be included in a Standard Terminal Arrival Route (STAR) or a Preferred IFR Route. (AIM)

structure
specialization of Preferential Route
part of Preferred IFR Route; STAR
instance connections
instance connection PAR (0, m) <-> Flight (0, m)
instance connection PAR (0, m) <-> Aircraft (0, m)
instance connection PAR (0, m) <-> Flight Manager (0, m)
instance connection PAR (0, m) <-> Air Traffic Manager (0, m)
instance connection PAR (0, m) <-> Traffic Manager (0, m)
message connection
Intrinsic only
object states
None
attributes
attribute Capacity (see Airspace/Ground Resource)
attribute Configuration (see Airspace/Ground Resource)
attribute Demand (see Airspace/Ground Resource)
attribute Load (see Airspace/Ground Resource)
attribute Location (see Airspace/Ground Resource)
attribute Name (see Airspace/Ground Resource)
attribute Saturation Threshold (see Airspace/Ground Resource)
attribute Separation Minima (see Airspace/Ground Resource)
attribute Usage Restrictions (see Airspace/Ground Resource)
services
The PAR class performs the implicit services create, connect, and release. A PAR object performs the implicit service access.
service Update Demand

Update the value of the Demand attribute to reflect the addition, change, or deletion of an instance connection.
service Update Load

Update the value of the Load attribute to reflect the addition, change, or deletion of an instance connection.

external input
None
external output
None
notes
None

specification PDAR - Preferential Departure and Arrival Route; a route between two terminals which are within or immediately adjacent to one ARTCC's area. (AIM)

structure
specialization of Preferential Route
instance connections
instance connection PDAR (0, m) <-> Flight (0, m)
instance connection PDAR (0, m) <-> Aircraft (0, m)
instance connection PDAR (0, m) <-> Flight Manager (0, m)
instance connection PDAR (0, m) <-> Air Traffic Manager (0, m)
instance connection PDAR (0, m) <-> Traffic Manager (0, m)
message connection
Intrinsic only
object states
None
attributes
attribute Capacity (see Airspace/Ground Resource)
attribute Configuration (see Airspace/Ground Resource)
attribute Demand (see Airspace/Ground Resource)
attribute Load (see Airspace/Ground Resource)
attribute Location (see Airspace/Ground Resource)
attribute Name (see Airspace/Ground Resource)
attribute Saturation Threshold (see Airspace/Ground Resource)
attribute Separation Minima (see Airspace/Ground Resource)
attribute Usage Restrictions (see Airspace/Ground Resource)
services
The PDAR class performs the implicit services create, connect, and release. A PDAR object performs the implicit service access.
service Update Demand

Update the value of the Demand attribute to reflect the addition, change, or deletion of an instance connection.
service Update Load

Update the value of the Load attribute to reflect the addition, change, or deletion of an instance connection.

external input
None
external output
None
notes
None

specification PDR - a specific departure route from an airport or terminal area to an en route point where there is no further need for flow control. It may be included in a SID or Preferred IFR Route. (AIM)

structure
specialization of Preferential Route

part of Preferred IFR Route; SID
instance connections
instance connection PDR (0, m) <-> Flight (0, m)
instance connection PDR (0, m) <-> Aircraft (0, m)
instance connection PDR (0, m) <-> Flight Manager (0, m)
instance connection PDR (0, m) <-> Air Traffic Manager (0, m)
instance connection PDR (0, m) <-> Traffic Manager (0, m)
message connection
Intrinsic only
object states
None
attributes
attribute Capacity (see Airspace/Ground Resource)
attribute Configuration (see Airspace/Ground Resource)
attribute Demand (see Airspace/Ground Resource)
attribute Load (see Airspace/Ground Resource)
attribute Location (see Airspace/Ground Resource)
attribute Name (see Airspace/Ground Resource)
attribute Saturation Threshold (see Airspace/Ground Resource)
attribute Separation Minima (see Airspace/Ground Resource)
attribute Usage Restrictions (see Airspace/Ground Resource)
services
The PDR class performs the implicit services create, connect, and release. A PDR object performs the implicit service access.
service Update Demand

Update the value of the Demand attribute to reflect the addition, change, or deletion of an instance connection.
service Update Load

Update the value of the Load attribute to reflect the addition, change, or deletion of an instance connection.

external input
None
external output
None
notes
None

specification Pilot - an aircraft operator (not including any other flight crewmember) or an on-board automation system with decision-making authority which interacts with ATC

structure
part of Aircraft
instance connection
None
message connection
message Message Available, from a Vehicle Communications System object that is part of the same Aircraft object as the Pilot object
message Perform Navigation, sent to the Vehicle Navigation System object which is part of the same Aircraft object as the Pilot object
message Request Adherence to Clearance, from a Flight Manager object
message Request Adherence to Clearance, from a Vehicle Manager object
message Request Aircraft Position, to the Vehicle Navigation System object which is part of the same Aircraft object as the Pilot object
message Request Amend Clearance, to the Arrival Clearance object which is part of the Flight Clearance object which is part of the same Aircraft object as the Pilot object
message Request Amend Clearance, to the Departure Clearance object which is part of the Flight Clearance object which is part of the same Aircraft object as the Pilot object
message Request Amend Clearance, to the En Route Clearance object which is part of the Flight Clearance object which is part of the same Aircraft object as the Pilot object
message Request Amend Clearance, to the Ground Clearance object which is part of the sameVehicle object as the Aircraft object of which the Pilot object is part
message Request Amend Flight Plan, to the Flight Plan object which is part of the same Flight object as the Aircraft object of which the Pilot object is part
message Request Amend Flight Plan & Clearance, from a Flight Manager object
message Request Amend Ground Vehicle Route, to the Ground Vehicle Route object which is part of the same Vehicle object as the Aircraft object of which the Pilot object is part
message Request Amend Ground Vehicle Route & Ground Clearance, from a Vehicle Manager object
message Request Flight Plan Amendment, to a Flight Manager object
message Request Ground Vehicle Route Amendment, to a Vehicle Manager object
message Request Report Aircraft Position, from a Flight Manager object
message Request Report Aircraft Position, from a Vehicle Manager object
message Request Transfer of Communications, from a Flight Manager object
message Request Transfer of Communications, from a Vehicle Manager object
message Send Aircraft Altitude, to a Vehicle Surveillance System object which is part of the same Aircraft object as the Pilot object
message Send Aircraft Identification, to a Vehicle Surveillance System object which is part of the same Aircraft object as the Pilot object
message Send Message, to a Vehicle Communications System object which is part of the same Aircraft object as the Pilot object
message Set Frequency, to a Vehicle Communications System object which is part of the same Aircraft object as the Pilot object
object states
None
attribute
Position - when human, one of two aircraft operators: the pilot-in-command or the second-in-command
services
The Pilot class performs the implicit services create, connect, and release. A Pilot object performs the implicit service access.
service create

Create and initialize, as specified for the implicit service create.
When a Pilot object is created and there does not already exist an Aircraft object of which the Pilot object is to be a part, requests the Aircraft class to create an Aircraft object of which the Pilot object is a part.
service Avoid Other Air Traffic

Ensure that other air traffic is avoided, whether based on personal observation, guidance from on-board equipment, or the direction of a flight manager.
service Avoid Other Ground Traffic

Ensure that other ground traffic is avoided, whether based on personal observation or the direction of a vehicle manager.
service Execute Flight

Perform the duties necessary to carry out the flight, including (for example)

Ensuring that the aircraft follows the flight plan.
Ensuring that clearances and instructions are carried out.

service Execute Movement

Perform the duties necessary to carry out the movement on the airport movement area, including (for example)

Ensuring that the aircraft or ground vehicle follows the planned ground plan.
Ensuri

An Object Oriented Analysis Of Air Traffic Control

APPENDIX AATC MODEL SPECIFICATIONS

APPENDIX A
ATC MODEL SPECIFICATIONS