Thomas Kozon

Changes in roles/responsibilities of Air Traffic Control under precision taxiing

In support of the NASA NGATS (Next Generation Air Transportation System) ATM (Air Traffic Management) Airportal Program, a realtime simulation study investigated the changes in roles and responsibilities for tower controllers brought about by the introduction of a new automation tool to achieve precision taxiing. The prototype tool, GoSAFE (Ground Operation, Situation Awareness and Efficiency Flow), is part of a future surface concept. This future surface concept envisages that future surface operations will involve taxi clearances containing precisely timed taxi routes. The study was conducted in two parts: (1) the first phase was used to identify issues with the original control jurisdiction that arose due to the introduction of increased surface traffic and automation in the tower, and (2) the second phase was used to design new areas of jurisdiction in coordination with the introduction of the automation technology and to test this new partnership. Four retired controllers participated in a Human-in-the-Loop real-time simulation study based on the Dallas/Fort Worth (DFW) International Airport (East side only). The controllers interacted with the tool under two conditions - one using datalink and another using voice to issue and deliver clearances to the pilots. Phase-1 data analysis results showed a significant difference in the average workload reported at different controller positions, with the local east controller being particularly busy. Phase-2 data analysis results indicated a more balanced redistribution of workload and communications among the controller positions. Comparison of the two phases has been described in the results section, which includes an analysis of the dependent measures of workload, situation awareness, and nature of communications. Comparison of the two conditions was also done for phase-2, for some of the dependent measures. The results suggested that changes in roles of new automation and human operators will need to be considered when designing procedures.

Procedures for off-nominal cases: Very closely spaced parallel runway operations

This study investigated procedures to increase capacity in the terminal area using a high-fidelity flight deck simulator. The concept was developed to achieve visual meteorological condition capacities under instrument meteorological conditions when landing aircraft on runways 750 ft apart. The purpose was to investigate procedures related to breakout maneuvers on final approach during off-nominal conditions. Fifty percent of the simulation runs had an off-nominal situation. The off-nominal situation was either the wake of the lead aircraft drifting too close to the trailing aircraft or the lead aircraft deviating from its course and blundering towards the trailing aircraft. The location of the off-nominal situation was also a variable. Results showed that the workload and situational demands experienced by pilots were higher in the off-nominal as compared to the normal scenario. Pilots executed a breakout maneuver earlier for wake intrusion than for aircraft deviation. The location and cause of the off-nominal situation did not have a significant impact on workload or situation awareness. In general, the pilots flew the breakout maneuver accurately and safely. The results provide an assessment of the procedures for breakout maneuvers during off-nominal conditions.

Using Models to Explore Air Traffic Controller Workload

When a new system, concept, or tool is proposed in the aviation domain, one concern is the impact that it will have on operator workload. As an experience, workload is difficult to measure in a way that will allow comparison of proposed systems with those already in existence. Chatterji and Sridhar (2001) suggested a method by which airspace parameters can be translated into workload ratings, using a neural network. This approach was employed, and modified to accept input from a non-real time airspace simulation model. The following sections describe the method and pilot test comparing a future airspace concept with a current day baseline in terms of workload levels. The results presented describe a preliminary analysis from using these models with the data from two non-real time model runs.