Task-Based Approach

The results of task-based modeling can be a valuable source of objective information for workforce planning, and FAA’s current model is a marked improvement over previous models that did not account for traffic complexity. The basic structure of the CAASD model, in which traffic activity is simulated and controller tasks and task times are associated with traffic, represents a logical approach to estimating task load.

Traffic Modeling

Compared with simple traffic counts, the simulations of traffic in the CAASD model provide a more complete picture of both the volume and nature of traffic activity in the en route domain. The traffic activity is modeled in sufficient depth and resolution to enable reasonable approximations of traffic complexity and associated controller tasks. CAASD can check the model results against records of actual traffic activity to improve the traffic modeling capabilities.

Task Coverage

The nine tasks in the model appear to be representative of the main R-side services that must be performed to work traffic—although whether the specific claim that 90 percent of R-side tasks are covered has not been well established. Compared with the other eight modeled tasks, the monitoring task is treated in the most confusing manner and is difficult to connect with traffic activity. A simpler and more transparent means of estimating monitoring time deserves consideration. While the model’s coverage of R-side tasks may be sufficient for traffic capacity analysis, the omission of all tasks performed by the associate controller makes its task load output inadequate for estimating PTT.

Task Time Derivation

Many of the task times in the model are derived from a separate modeling process known as Goals, Operators, Methods, and Selection Rules (GOMS). For seven of the nine modeled tasks, GOMS is used to derive

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