Human-centered automation of air traffic control operations in the terminal area

Cover titleNovember 2, 1994Series statement handwritten on coverProposal for the Interdepartmental Doctoral Program in Human Factors and AutomationIncludes bibliographical references (p. 70-73)Introduction: Air Traffic Control operations are described extensively in the ATC manuals such as the Airman's Information Manual [1] and the ATC Controller's Handbook [2]. Mathematical analysis has also been conducted for the ATC operations as evident in the many theses that have been published in ATC research [3, 4, 5]. A brief description is due here however in order to provide a background for the following document. There are six major ATC functions in the terminal area and a summary of their description in Sadoune's thesis [5] follows: Flow Management: The flow management purpose is to provide efficient transition between the en-route corridors and the terminal area through the metering fixes. The en-route corridors are the airways connecting the airports, the terminal area is the designated space around the airport, and the metering fixes are the points at which aircraft enter the terminal area under the flow control process called metering. The flow management system is capable of delivering the aircraft to the metering fix at predetermined time, altitude, and speed, minimizing fuel consumption and flight time. Beyond the metering fix however the concern in no longer fuel and cost, it is the separation between the aircraft and the landing schedule. Ground-based flight path generation is needed at that point. Runway Scheduling: The runway capacity is the limiting factor of the flow of traffic at congested airports. There are many reasons why runways are not used efficiently in the current tactical practice. These include the independent scheduling of landings and takeoffs, the ad hoc fashion in which takeoffs are inserted between landings, and the common use of the first-come-first-serve approach which is fair but not optimal. Runway scheduling is a queuing process and can be optimized for maximum throughput, long term service, and minimum delays of aircraft, taking into account fuel consumption, duration of flight, and other factors. The difficulty is in the dynamic nature of the schedule where modifications are needed as new entrants arrive or as environmental conditions change. The determination of the runway capacity and its improvement through the use of advanced technologies are discussed in Flow Control: Through traffic redistribution the flow control process helps smooth the demand fluctuations leading to a controlled number of aircraft simultaneously present in the terminal area. Two processes accomplish flow control: metering and holding. Metering divides the approach to the airport into successive stages between metering fixes. The flow management system delivers the aircraft to the metering fixes at the predetermined time, altitude, and speed. Holding points are assigned where holding aircraft are stacked and isolated from traffic. Holding aircraft circle in holding patterns awaiting landing clearance. Therefore, while metering moves the delays resulting from the runway capacity upstream, holding extends the flight path in time to accommodate arrival delays. These practices however can result in idle runway time in favor of more flow control leading to less efficient use of the runway. Flight Path Generation: There are standard routes both from the terminal area entry points to the runway for approach and from the runway to the en-route corridors for departure. These predefined routes can be used at low traffic flow rates, and add to the precision since automatic flight control systems are capable of flying along them automatically. However they are not optimal in using the space, or in exploiting the aircraft capabilities, or in maximizing the runway capacity. Automated flight path generation allows the incorporation of the space organization, the ATC separation criteria, the landing and takeoff schedule, the aircraft dynamics and performance limitations, and the maneuvering characteristics of the pilot in generating more optimal and flexible paths. This subject will be emphasized further in this document. Path Conformance Monitoring: In order to supervise the execution of the flight path plan, the radar surveillance system provides vague and non-precise measurement of the position of the aircraft. The controllers base their estimates of the conformance on 2-dimensional radar displays, and have to wait few intervals to estimate the direction of the aircraft. To adjust for the path conformance error the controllers issue heading, altitude, and speed clearances (vectors) to the pilots. Communication between controllers and pilots is done via radio transmission. Errors result from misunderstanding between the pilot and the controller, pilot response, as well as wind and unexpected atmospheric disturbances. Again new technologies and more automation are expected to improve the path conformance capabilities. These include better surveillance using satellites, digital data links for communication between the controller and the pilot, and display of the path to the pilot on board the aircraft. Questions of resolution and threshold of the conformance error become critical to the automation of the monitoring function. Hazard Monitoring: This includes detecting possible collisions between aircraft and with the ground. There is a trade off between false alarms and missed alarms in setting the threshold for the hazard alarm. Namely the more conservative the alarm threshold is set, the less is the risk of collision due to a missed alarm. But the disturbance to the traffic flow caused by the large number of false alarms is higher

Departure operations at Boston Logan International Airport

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2001.Includes bibliographical references (p. 199-203).In order to support the development of improved methods for departure operations, the flow constraints and their causalities --primarily responsible for inefficiencies and delays-- need to be identified. This thesis is an effort to identify such flow constraints and gain a deep understanding of the departure process underlying dynamics based on field observations and analysis conducted at Boston Logan International Airport. It was observed that the departure process forms a complex interactive queuing system and is highly controlled by the air traffic controllers. Therefore, Flow constraints were identified with airport resources (runways, taxiways, ramp and gates) and with air traffic controllers due to their workload and control strategies. While departure delays were observed in all airport components, flow constraints manifested mainly at the runway system, where the longest delays and queues concentrated. Major delays and inefficiencies were also observed due to flow constraints at National Air Space locations downstream of the airport, which propagate back and block the departure flow from the airport. The air traffic controllers' main strategies in managing the traffic and dealing with the flow constraints were also identified.(cont.) Based on these observations, a core departure process abstraction was posed consisting of a queuing element (representing the delays) and a control element (representing the air traffic controller actions). The control element represents blocking the aircraft flow, to maintain safe airport operation according to Air Traffic Control procedures and to regulate the outbound flow to constrained downstream resources. Based on this physical abstraction, an analytical queuing framework was developed and used to analyze the departure process dynamics under three different scenarios: the overall process between pushback and takeoff, departure sub-processes between controller/pilot communication events and under downstream restrictions. Passing which results mainly from aircraft sequencing and their suspension under special circumstances (such as downstream restrictions) was used as a manifestation of the control behavior. It was observed that Logan Airport exhibits high uncertainty and limited sequencing, hindering the air traffic controllers' ability to efficiently manage the traffic and comply with restrictions. In conclusion, implications for improved methods for departure operations are inferred from the observations and analysis.by Husni Rifat Idris.Ph.D

Presentations from the 1995 MIT/industry cooperative research program annual meeting.

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Presentations from the 1996 MIT/industry cooperative research program annual meeting.

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Queuing dynamics and control of departure operations at Boston Logan Airport

Thesis (S.M.)--Massachusetts Institute of Technology, Sloan School of Management, Operations Research Center, 2001.Includes bibliographical references (p. 91-95).The Departure Planner (DP) is a concept for a decision-aiding tool that is aimed at improving the performance of departure operations at major congested airports. In order to support the development of DP tools and other improved methods for departure operations, this thesis is an effort to gain a deep understanding of the underlying dynamics of the departure process based on field observations and data analysis conducted at Boston Logan International Airport. It was observed that the departure process is a complex interactive queuing system and a highly controlled system as the air traffic controllers manage the traffic. Based on these observations, a core departure process abstraction was posed which consists of a queuing element that represents the delays and a control element that represents the air traffic controller actions. Namely, the abstraction represents the control element by blocking the flow of aircraft in order to maintain the safe operation of the airport resources according to the A TC rules and procedures and to regulate the outbound flow to constrained downstream resources. Based on this physical abstraction, an analytical queuing framework was posed and used to analyze the departure process dynamics under different scenarios: the overall departure process between pushback and takeoff, departure sub-processes between controller/pilot communication events and under the effect of downstream restrictions. Passing was used as a manifestation of the control behavior, where passing results mainly from sequencing of aircraft and their suspension under special circumstances such as downstream restrictions. Insights about the departure process queuing dynamics and control behavior are discussed. In particular it was observed that at Logan airport there is a high level of uncertainty and a limited level of sequencing control, hindering the ability of the air traffic controllers to manage the traffic efficiently and in compliance with restrictions.by Husni Rifat Idris.S.M

A simulation of aircraft motion on the airport surface

Cover titleMarch 16, 1994Series statement handwritten on coverIncludes bibliographical references (p. 40)This paper describes the design and implementation of a real-time simulation of aircraft motion on the ground at airports. The aircraft Ground Motion Simulator (GMS) is designed to realistically simulate tower, ground, and apron aircraft control. The simulation includes high-fidelity graphic views, in color, of airport ground activity. It simulates air traffic operations in real time for all stages of flight from take-off to landing as well as all phases of ground movement of aircraft including landing roll, taxiing, yielding, platooning, parking, pushback, and takeoff roll. The capability to simulate aircraft movement on airport taxiways and runways provides a realistic environment for testing the planning processes regarding the management of departing traffic and its interactions with aircraft landing at an airport. The GMS simulates the environment at any arbitrary airport and interfaces through a fast, two way data communications link to an existing Air Traffic Control simulation facility. The GMS consists of a host computer workstation, an experimenter's station, one or more traffic controller stations, and one or more pseudopilot stations. The graphical user interface and the graphical displays were developed in object-oriented C on the X/Windows graphics system on UNIX workstations