Survey of Traffic and Radar Controller Communication and Workload Fedja Netjasov, Tatjana Krstic and Igor Poltoracki University of Belgrade Faculty of Traffic and Transport Engineering Division of Airports and Air Traffic Safety .

Air Traffic Controller Tasks Traffic monitoring; Conflict detection and resolution; Vectoring; Communication with Pilots and other Controllers; Etc.

Controller Workload and Communication - Pilot Study Belgrade ACC, sector North East; March 17/18 2000, 4 hours each day; Recordings: Tape recorder – radio frequency, telephone, interphone; Tape recorder – working position; Video camera – radar display;

Structure of the Study Analysis of traffic characteristics; Analysis of controller communication vs. traffic; Analysis of controller workload vs. traffic; Analysis of controller workload vs. communication.

Analysis of Traffic Characteristics Cumulative number of aircraft in sector; Max number of simultaneously present aircraft in the sector; Cumulative number of flight strips on the console; Max number of simultaneously present flight strips on the console; Total number of potential conflicts; Total number of transfers.

Number of flight strips (March 17) Number of aircraft (March 17) Number of transfers and potential conflicts (March 17)

Controller’s communication

Analysis of Communication Total number of controllers communications during 15 min intervals; Total duration of controllers communications during 15 min intervals; Structure of conversations; Average pauses between conversations.

Structure of total number of conversations Structure of total duration of conversations Structure of conversations with aircraft crews Structure of conversations with planning controller

Analysis of Communication (cont.) No. of conversations vs. No. of aircraft Total duration of conversations vs. No. of aircraft

Analysis of Workload NASA TLX (Task Load Index) Method for subjective assessment of controller workload Relevant factors for workload assessment: Mental demand; Physical demand; Temporal demand; Performance; Frustration level, and Effort

Comparative Analysis of Traffic Parameters and Workload Cumulative Number of Active Strips, Number of Potential Conflicts and Workload Index Controller No.1 Number of Aircraft in Sector, Number of Potential Conflicts and Workload Index Controller No.1

Comparative Analysis of Traffic Parameters and Workload (cont.) Workload Index vs. Number of Aircraft in the Sector Workload Index vs. Number of Aircraft in the Sector – classes

Comparative Analysis of Communication and Workload Changes of Number of Conversations and Workload Index (March 17) Changes of Duration of Conversations and Workload Index (March 17)

Comparative Analysis of Communication and Workload (cont.) Workload Index vs. Number of Conversations Workload Index vs. Duration of Conversations

Conclusion Purpose of presented survey was to determine engagement of tactical controller on communication and influence of this engagement on estimated workload; Analysis of conversation structure showed that tactical controller most frequently communicate with aircraft crews and then with planning controller; It was concluded that the communication is important factor influencing controller workload, i.e. the increase of number and duration of conversation leads to workload increase;

Conclusion (cont.) Analysis showed also that the NASA - TLX method for workload assessment is sensitive to objective changes of controller workload; However, application of this method have not overcomed significant individual differences between controllers in understanding the term workload, as well as its assessment.

Further research Continuation of survey with aim of sample increase, which would enable determination of functional relationship between workload and traffic/communication parameters for purpose of workload prediction; To see the impact of new communication technology (e.g. data link) on communication parameters and on workload.

Thank you for your attention University of Belgrade Faculty of Transport and Traffic Engineering Department of Air Transport Division of Airports and Air Traffic Safety http://apatc.sf.bg.ac.yu apatc@sf.bg.ac.yu Vojvode Stepe 305, 11000 Belgrade Serbia and Montenegro tel: +381 11 3091 352 fax: + 381 11 2496 476