The Future of Air Traffic Control Human Operators and Automation (1998) / Chapter Skim
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6 Strategic Long-Range Planning
6 Strategic Long-Range Planning
Pages 156-183
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From page 156... ...
CENTER TRACON AUTOMATION SYSTEM Functionality The primary objective of the center TRACON automation system (CTAS) is to assist the air traffic controller in optimizing the traffic flow in the terminal area (Erzberger et al., 1993~.
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From page 157... ...
. The actual implementation of the plan generated by the traffic management coordinator with the assistance of the traffic management advisor is carried out by the other two elements of CTAS, the descent advisor, and the final approach spacing tool.
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From page 158... ...
is the corresponding advisory tool designed to support the TRACON controller in implementing the traffic management advisor plan, by issuing speed and heading advisories and runway assignments necessary to maintain optimal spacing between aircraft of different classes (Davis et al., 1994; Lee and Davis, 1995~. An important secondary function of the final approach spacing tool is its ability to rapidly adjust to and reschedule on the basis of unexpected events like a missed approach or a sudden unexpected runway closure.
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From page 159... ...
During the mid-199Os, this system has received several field tests at Dallas-Fort Worth International Airport and at the Denver airport and center. It is also being installed at Schiphol Airport in Amsterdam, the Netherlands.
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From page 160... ...
That is, nothing in CTAS qualitatively alters the way in which controllers implement their control over the aircraft. Human Factors Issues Cognitive Task Analysis A cognitive task analysis reveals that CTAS supports the controller's task in three critical respects, addressing the vulnerabilities identified in the panel's Phase I report.
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From page 161... ...
Finally, CTAS, particularly the final approach spacing tool, supports the controller's ability to deal with the high workload imposed by unexpected and complex events, characterized for example by a missed approach or an unanticipated runway closure. The first and second of these tasks primarily affect the efficiency of system performance, whereas the latter appears to have direct and beneficial safety implications.
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From page 162... ...
(in press) noted the increase in controller confidence after they had used the system (and relied on the final approach spacing tool advice)
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From page 163... ...
Skill Degradation As with complacency, so with skill degradation: CTAS has not been used long enough to determine whether this is an issue. Yet it is easy to imagine circumstances in which controllers increasingly begin to rely on CTAS advice, relaying this as instructions to pilots, losing the skills at selecting maneuvers on their own.
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From page 164... ...
There are three interrelated automation functionalities that can potentially assist in these goals: conflict probes, interactive planning tools, and conflict resolution advisors. The conflict probe is essentially a preview of the current flight trajectory of a given aircraft, to assess whether it will create a loss of separation with another aircraft at some time in the future.
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From page 165... ...
. A less mature level of development characterizes interactive decision aids, two of which we describe in some detail below: the user request evaluation tool developed for use in the United States and the highly interactive problem solver (HIPS)
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From page 166... ...
. The key interactive feature of the user request evaluation tool is the planning mode, which allows the D-side controller to play what-if scenarios by graphically examining the implications of alternative instructions that could be given to one or both aircraft.
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From page 167... ...
. Human Factors Implementation As developed at the MITRE Corporation, the user request evaluation tool received a substantial amount of input from controllers in specifying both functionality and the interface, and such input was guided by human factors professionals.
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From page 168... ...
Instead, HIPS is explicitly based on a human-centered approach and, like the user request evaluation tool described above, tries to keep the controller in the loop by restructuring
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From page 169... ...
; the UK CAA (Civil Aviation Authority) ; the NATS (National Air Traffic Services)
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From page 170... ...
New Error Forms: Mode Errors These systems appear to have been designed to be relatively simple, with few modes to invite confusion. For the user request evaluation tool, a concern is whether the portrayal of flight paths in the planning mode could become confused with its portrayal in the active traffic mode.
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From page 171... ...
Should, however, the R-side controller begin to shift attention to the user request evaluation tool to or the highly interactive problem solver display, one can envision negative workload implications, to the extent that visual resources are removed from the plan view display. Also, it is possible that R-side situation awareness could degrade if the controller adopts a strategy of automatically accepting recommendations based on the tool, without carefully thinking through the implications of those suggestions.
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From page 172... ...
As a result, the feedback provided by graphical look-ahead tools may enable the controller to develop better speed control skills. Communication and Coordination Both the user request evaluation tool and the highly interactive problem solver are designed to support more long-range strategic planning.
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From page 173... ...
. A sudden failure of the user request evaluation tool or conflict probe system could thereby leave the R-side controller more vulnerable in issuing the rapid tactical commands necessary to avoid conflict situations.
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From page 174... ...
The controller also has available display tools for short-term projection of flight paths. Thus, the controller's cognitive skills in planning and the spatiotemporal projection of flight paths, combined with display aids, form the basis for the current system of air traffic management.
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From page 175... ...
In an experimental flight management system concept being evaluated by Eurocontrol, aircraft intentions (a four-dimensional trajectory derived by the system) would be down-linked to air traffic management, who would then up-link their requirements in terms of route or time constraints.
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From page 176... ...
In this respect, the 4-D contract concept is similar to the U.S. air traffic management concept of free flight, albeit in a more limited form: the degree of pilot freedom lies somewhere between current practices and "advanced" free flight, in which aircraft have much greater flexibility in setting and changing flight paths (RTCA, 1995b)
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From page 177... ...
The development of the 4-D contract concept has been accompanied by attention to human factors enhancements, particularly in the controller's tools and operating procedures. One product of the PHARE effort will be a set of integrated controller tools, known as the PHARE advanced tools, that incorporates the following capabilities:
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From page 178... ...
, as well as high levels of user acceptance (National Air Traffic Services Limited, 1996~. Failure Recovery When the system has saturated the airspace and a partial failure occurs, the use of 4-D contracting tools, like CTAS and interactive conflict resolution tools, may lead to problems in achieving effective and timely recovery.
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From page 179... ...
To address efficiency concerns, the FAA, in collaboration with NASA, is undertaking large-scale development activities to provide controllers, pilots, airfield managers, and airline operations personnel with cues that enhance situation awareness and with automated support of surface traffic planning. The surface movement advisor project, a joint activity of the FAA and NASA, is being developed to improve the efficiency with which airport facilities operate.
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From page 180... ...
; implementation of wireless mobile computing technologies to promote wider surface movement advisor data access; and integration of the advisor with surface traffic development and test facilities (National Aeronautics and Space Administration, 1996~. Human Factors Implementation The surface movement advisor is being developed according to the "build a little, test a little" development philosophy that includes early involvement of users and human factors professionals and ongoing evaluations using mixed methodologies (see Chapter 9 for a discussion of the advantages of these activities)
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From page 181... ...
The combination of loss of situation awareness and skill degradation can result in the operator's inability to respond adequately to the failure of the automation. In the case of the surface movement advisor, these risks are introduced at multiple points in the team structure that includes controllers, pilots, airport managers, and airline operations personnel.
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From page 182... ...
For example, tools currently available only to some personnel selectively provide such information as airline schedules, flight plans, gate information, various weather parameters, and runway configuration; the surface movement advisor may combine these tools, or future versions of them, and redistribute the information to additional personnel. In addition to the issue of developing a consistent humancomputer interface across the integrated tools, their combination may introduce possibilities for redefining tasks.
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From page 183... ...
The evolution of changes should be centrally monitored and coordinated by a human factors research and development oversight organization.
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