The effect of predictive aid usage on controller strategies & mental demand under direct routing

The implementation of Free Flight, a strategic goal for improving air traffic capacity in the National Airspace System, has raised many concerns amongst controllers regarding safety. A principal concern is the inability of the controller to project future aircraft states due to increased levels of mental workload and breakdowns in situation awareness. This paper looks at a by-product of the Free Flight concept, namely Direct Routing. It proposes a modified interface, which is representative of a combined data-link and conflict detection aid that would help in giving predictability back to the controller. Results showed that the aid served to ameliorate the effects of high airspace load on mental demand under an analogue of Direct Routing conditions. The results also highlight how controller strategies can vary when dealing with a variety of requests for routing changes. The implications of these results are discussed