Controller workload has been a focal topic in air traffic management research because it is considered a key limiting factor to capacity increase in air traffic operations. Because workload ratings are subjective and highly prone to individual differences, some researchers have tried to replace workload with more objective metrics, such as aircraft count. A significant caveat in substituting these metrics for workload ratings, however, is that their relationships are non-linear. For example, as the number of aircraft increases linearly, the controller's perceived workload jumps from low to high at a certain traffic threshold, resulting in a stepfunction increase in workload with respect to aircraft count, suggesting that controllers perceive workload categorically. The non-linear relationship between workload and aircraft count has been validated using data collected from a recent study on the En Route Free Maneuvering concept element (Lee, Prevot, Mercer, Smith, & Palmer, 2005). The results suggest that objective metrics, such as aircraft count, may not be used interchangeably with subjective workload. In addition, any estimation on workload should not be extrapolated from a set of workload measures taken from an experiment since the extrapolated workload is likely to significantly underestimate workload.
In recent years, NASA has initiated the development of a focused near-to mid-term concept called "Integrated Demand Management" (IDM) under the Airspace Operations and Safety Program (AOSP). The focus of the research has been to develop more powerful, integrated operations and tools for managing trajectory constraints, leveraging existing systems and adding new automation tools and methods where needed. The IDM concept is predicated on the idea that in situations where the capacity of critical resources (such as airspace or airports) is insufficient to meet demand, a better match between available capacity and the predicted demand would significantly benefit the operations, with potential improvements in throughput, delays, and efficient flight trajectories. In current operations the reasons for the capacity/demand mismatches can vary, and range from problems due to structural limitations (e.g., surface capacity at high-volume airports, high-complexity en route or arrival airspace); to wind-related capacity changes; to the more severe, unstable and dynamic mismatches that occur with convective weather. The IDM solution proposes to address the demand / capacity mismatches by using the strategic flow management capabilities within the traffic flow management system (TFMS) toolset to "pre-condition" demand into the more tactical time-based flow management (TBFM) system, which should enable TBFM to better manage delivery to the capacity-constrained resource(s). The intent of IDM is to leverage the strengths of each of these systems to produce an integrated solution that is more powerful and robust than either could provide alone, or than the two would provide today as uncoordinated systems.Newark Liberty International Airport (EWR) was chosen to be the focus of our initial design problem for several reasons. EWR routinely sees scheduled demand at or near airport capacity through much of the day with a varying mix of short-haul and long-haul flights. Although this is usually managed effectively using miles-in-trail and TBFM metering, close-in departures can experience excessive and unpredictable ground delay if the overhead flow is saturated. In the initial development of IDM concept, an alternative solution to this volume problem was proposed that integrates 3 key capabilities: 1) Collaborative Trajectory Options Program (CTOP) capability within TFMS to issue traffic management initiatives that can "strategically" manage demand into the TBFM system; 2) TBFM capability closer to the destination airport to "tactically" manage delivery to the capacity-constrained destination; and 3) required-time-of-arrival (RTA) capability on the flight deck to provide a more controlled traffic demand using the CTOP derived schedule into the TBFM domain.The IDM concept development is ongoing and iterative, based on inputs from the FAA and airline stakeholders, as well as on insights gained from a series of human-in-the-loop
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.