In this part we review automation features and associated human factors issues for a number of existing and proposed programs and products that apply automation to air traffic control tasks. In Chapter 3 we review fundamental surveillance (radar, global positioning system, and weather) and communication (bandwidth, voice switching and control system, and data link) systems. In Chapter 4 we review systems that process and present flight information to pilots (flight management system) and to air traffic controllers (ground-based flight data processing). In Chapter 5 we review systems that support immediate conflict avoidance: the traffic alert and collision avoidance system (TCAS), the converging runway display aid (CRDA), the precision runway monitor (PRM), and airport surface collision avoidance systems. In Chapter 6 we review strategic long-term planning: the center TRACON automation system (CTAS), the conflict probe and interactive planning, four-dimensional contracts, and the surface movement advisor (SMA). In Chapter 7 we review training and maintenance systems.

The goal of our analysis for each system or component is to examine potential issues in human factors and automation, to identify strengths and weaknesses in the system, and to suggest future research directions. With regard to research, we believe that the need for data collection and comparison is indicated in a number of areas in which changes are projected and the implications for the human operator are uncertain. The framework used for analyzing human factors issues includes the categories of workload, training and selection, organizational factors, and cognitive task analysis, in which we perform our own breakdown of the cognitive components of the task. The framework used for identifying critical

automation issues includes the categories of mode errors, trust, skill degradation, mental models, and communication and organization. Researchers and developers interested in the evaluation of current and future automated systems should find these frameworks useful.

This introduction includes a set of tables that map automation programs and products to controller tasks performed in each type of facility. A glossary defining the acronyms noted in the tables and elsewhere in the report appears in Appendix A. Our purpose in presenting the tables is to offer a broad framework for the more detailed discussion of specific instances of automation and to present a general overview of trends.

Tables II.1 through II.4 summarize current, developmental, and contemplated applications of automation to air traffic control tasks for the en route, TRACON, tower, and oceanic environments, respectively. The tables include traffic management and flight service tasks for each environment, as appropriate.

In the Phase I report we acknowledged and discussed in some detail the importance of the flight service station facilities and the Air Traffic Control System Command Center facility. Our current treatment of these facilities is limited here to referencing the automated features of these facilities that support traffic management functions for the en route, TRACON, tower, and oceanic environments. In addition, we note the distinction between air traffic control and airway facilities specialists; however, the tables include and the text discusses in detail the automated features of airway facilities systems that support air traffic control tasks.

The tasks identified in Tables II.1 through II.4 are grouped into the following cognitive functions and presented in descending order of cognitive complexity:

1. Planning strategies and resolving conflicts,

2. Predicting long-term events,

3. Comparing criteria and predicting short-term events,

4. Transmitting information,

5. Remembering, and

6. Identifying relevant items of information.

For each environment and for each controller task, we identify automated features of the air traffic control system that are: (1) currently implemented, having been developed, tested, and fielded (although not necessarily implemented in all facilities for a given environment); (2) in development (although future upgrades or product improvements with additional automated features may remain tentative); and (3) under future consideration (development may be planned or concepts may be under consideration). Since the third category reflects concepts rather than detailed designs, the mapping of those items to functions that they may automate is especially tentative; our mapping is based on a broad interpretation of the automation concepts for items in that category. For example,

Table II.3 identifies, for the tower environment, extensive future capabilities for the surface movement advisor (SMA); some of the capabilities (especially higher level capabilities) are based on conceptual developments rather than on firm program plans.

Systems in development or under future consideration often include modernization of previously automated functions (i.e., improved computing speed, accuracy, capacity, memory) and may or may not add automated features beyond those already provided by the systems that they replace. The tables include such systems only when they add automated features, and only the added automation features (not those that are simply being replicated) are identified in the tables. For example, the display system replacement (DSR) will modernize the display channels and displays of the en route system. It will replicate current processing of flight and radar data and will preserve current automation features. Therefore, Table II.1 identifies only the additional conflict probe feature added by the DSR.

Some air traffic control tasks are highly automated; others are performed primarily by the air traffic controller, who receives assistance from automation. For example, the tasks of sensing, computing, and displaying the position of aircraft are highly automated; they are performed by the elements of the radar processing system. However, the task of resolving traffic conflicts is performed largely by the controller, who may receive automated assistance from such systems as the CTAS or the user request evaluation tool (URET). In the tables, features that supply a high degree of automation for a given task are highlighted; features that provide automated assistance to controllers, who perform the task, are not. The dichotomy applied here between highly automated features and automation assistance features represents a forced choice judgment. We do not attempt here to apply the more complex treatment of levels and dimensions of automation, discussed in detail in Chapter 1.

The primary sources for the automation programs identified in the tables and discussed in this section are the Federal Aviation Administration's National Airspace System Architecture description (1996a) and its Aviation System Capital Investment Plan (1996b). The primary source for the identification of controller tasks is the controller task listing developed and reported under the FAA's separation and control hiring assessment program.

Key automation features and functionality are discussed in greater detail elsewhere in this report. Here we first briefly describe areas of automation not addressed in detail in other sections: flight services and oceanic control. In addition, we outline the modernization efforts that are prerequisite for planned product improvements for en route centers, TRACONs, and towers.

Many flight service functions are currently automated. Preflight briefings and instrument flight rules/visual flight rules flight plan filing services are available on a walk-in basis or via telephone. These services are also available via personal computer through the direct user access terminal system (DUATS). Preflight information is also available through dial-in lines for the automated weather observing system (AWOS) and the automated surface observing system (ASOS), whose data are also broadcast automatically.

The FAA is considering virtually complete automation of flight services, with the goal of enabling pilots to self-brief and to file flight plans without contacting flight service specialists. A contemplated operational and supportability implementation system (OASIS) would address these goals.

The current oceanic air traffic control system does not rely on radar coverage, and so direct surveillance is not used over most of the ocean. Navigation is performed primarily with on-board inertial navigation systems, and pilots report their positions to controllers via high frequency voice radio. The current oceanic display and planning system (ODAPS), deployed in Oakland and New York, provides a display of aircraft positions, based on extrapolation of periodic voice position reports from pilots and on filed flight plans. In addition, the dynamic ocean tracking system (DOTS) assists the controller to develop routes that take advantage of favorable wind and temperature conditions, and also projects aircraft movement to identify airspace competition and availability. The telecommunications processor (TP) has replaced the flight data input/output computer system (FDIO) for oceanic controllers; the processor includes a message scrolling capability.

The FAA plans future development of data link capabilities and improved navigation and surveillance data, which are required to support desired automation features for the oceanic environment. Data link capabilities would include the oceanic data link (ODL) under development, as well as future controller-to-pilot data link (CPDL). The global positioning system and automatic dependent surveillance are also considered enabling technologies for automation in this environment. An improved air traffic control interfacility data communications (AIDC) is also posited. The umbrella programs for oceanic automation are the advanced oceanic automation system (AOAS) and the oceanic automation program (OAP). These long-term programs would build on the data provided by new surveillance, navigation, and communication systems to achieve levels of automation commensurate with those of the domestic en route environment. The oceanic environment is also the locus of one of the early precursors to free flight, embodied in the procedures of oceanic in-trail climb (discussed in Chapter 9).

Data link, the global positioning system, and automatic dependent surveillance developments are discussed in greater detail in Chapter 3.

The en route computer display channel processor, the display channel controller processor, and plan view displays are being modernized through the display system replacement (DSR). This modernization program will retain all the features of the existing system, will support an additional conflict probe capability, and is planned to accommodate future enhancements that may include automated features discussed elsewhere in this report.

The standard terminal automation replacement system (STARS) is a modernization program that will replace ARTS processors and displays. STARS will replicate ARTS functions and will therefore include the automated features of ARTS. STARS is planned as an expandable system that will accommodate future automation enhancements for the TRACON.

The FAA is planning a tower integration program whose main goals are the consolidation of the disparate displays and controls in the current tower and the addition of automation enhancements.

Each of these modernization efforts includes the provision of new workstations for controllers.

The voice switching and control system is a form of air traffic control automation that employs digital logic, controlled by a touch screen interface above the controller's display, to change and reconfigure radio frequencies and communication links, in order to directly route (or reroute) communications to desired parties (Perry, 1997). It is a highly flexible and adaptable system, enabling controllers and supervisors to easily reconfigure communications within a sector, or supervisors to do so within an entire facility. The system has been well received by controllers because it replaces time-consuming and inflexible operations and because of its greater reliability; however, a survey of air traffic controllers revealed that its implementation has produced certain problems (Sarter and Woods, 1997). For example, 28 of the 58 controllers responding to the survey indicated instances in which they had been ''surprised" by a reconfiguration of the system that had been carried out by a remote operator; at the time they were not aware of the reconfiguration, but only discovered it later, when they tried to perform operations that failed in the new reconfigured mode. The potential for such mode errors (see Chapter 1) is perhaps an inevitable downside of the flexible aspects of some automation functions. Their presence may have serious consequences, and their possible emergence in other systems should be anticipated,

with attention given to design features that make mode changes clearly observable to all participants.

1. A considerable amount of automation has already been applied to air traffic control tasks for the en route, TRACON, and tower environments, and future automation is likely to be significant for all environments.

2. Current automation is applied to support controller tasks across all levels of cognitive complexity. However, the application of highly automated features, which often virtually replace controller actions, has to date been largely reserved for tasks of lower cognitive complexity. When automation is currently applied to tasks of higher cognitive complexity, the automation provides assistance to controllers, who perform and are responsible for the tasks.

3. Given that tasks of lower cognitive complexity have to date received "fuller" automation, the trend toward a more highly automated system appears more revolutionary—and faces its greatest challenge—at higher levels of cognitive complexity (long-term prediction, planning, and conflict resolution).