relevant in future systems, because it was assumed that the displays would be graphic and the numerical computations would be accomplished by the equipment. Skills and abilities related to verbal and spatial reasoning and to selective attention received mixed ratings, although all agreed that some level of these skills and abilities would be needed, particularly when the controller would be asked to assume control from the automation.
The general conclusion from the work of Manning and Broach (1992), as well as from analyses of proposed automation in AERA 2 and AERA 3 (Reierson et al., 1990), is that controllers will continue to need the same cognitive skills and abilities as they do in today's system, but the relative importance of these skills and abilities will change as automation is introduced. The controller in a more highly automated system may need more cognitive skills and abilities. That is, there will be the requirement for more strategic planning, for understanding the automation and monitoring its performance, and for stepping in and assuming manual control as needed. An important concern, echoed throughout this volume, is the need to maintain skills and abilities in the critical manual (as opposed to supervisory) control functions that may be performed infrequently. Dana Broach (personal communication, Federal Aviation Administration Civil Aeromedical Institute, 1997) has indicated that the Federal Aviation Administration is currently developing a methodology to be used in more precisely defining the cognitive tasks and related skill and ability requirements as various pieces of automation are introduced. Once in place, this methodology should be central to identifying possible shifts in both establishing selection requirements and designing training programs.
The human performance vulnerabilities that have been discussed thus far may be characteristic of fixed or static automation. For example, difficulties in situation awareness, monitoring, maintenance of manual skills, etc., may arise because with static automation the human operator is excluded from exercising these functions for long periods of time. If an automated system always carries out a high level function, there will be little incentive for the human operator to be aware of or monitor the inputs to the function and may consequently not be able to execute the function well manually if he or she is required to do so at some time in the future. Given these possibilities, it is worthwhile considering the performance characteristics of an alternative approach to automation: adaptive automation, in which the allocation of function between humans and computer systems is flexible rather than fixed.
Long-term fixed (or nonadaptive) automation will generally not be problematic for data-gathering and data integration functions in air traffic management because they support but do not replace the controller's decision making activities (Hopkin, 1995). Also, fixed automation is necessary, by definition, for