Student Air Traffic Controllers' performance under conditions of increased workload
Authors: Pilmannová Terézia , Hanakova Lenka , Socha Vladimir , Freigang Michal , Schmidt Stanislav 
Published: June 2023

The work of an Air Traffic Controller (ATCO) involves a constantly changing mental workload and the occurrence of stressful situations to which one must react adequately. Candidates for this profession are expected to demonstrate sufficient resilience and adaptability to such situations already in the selection procedure and during the training process. However, the complexity of Air Traffic Controllers' tasks has increased dramatically in the last decades. A transformation of the ATCO training syllabus was inevitable to ensure the ability of future ATCOs to cope with this changing environment. This change has mainly become apparent in the number of practical skills a trainee has to possess even before initiating the On the Job (OJT) training. Training Organizations are constantly optimizing training processes to prepare a candidate able to withstand challenging situations with varying workloads.To investigate trainees' reactions to increased workload in the context of conducted errors, an experiment was organized examining 30 subjects that participated in a simulator exercise with increasing intensity. The subjects of the experiment were Department of Air Transport students with no particular experience in ATC but considerable knowledge of standards and procedures in air traffic control and familiarity with the simulation environment. It is therefore supposed that the level of skills and knowledge of the subjects are equivalent to student Air Traffic Controllers conducting the basic training. The aim of the experiment was to assess the impact of increased workload, utilizing ECG measurement, on the trainees' performance and subsequent error analyses. The increased workload is achieved by continuously increasing the difficulty of the exercises on the ATC simulator. To analyze, the ECG measurement, data, including R-R intervals, were processed by a short Fourier transform(STFT), filtered and further processed by HRVAS (in Matlab) by time-frequency analysis. Data were processed for Low and High Frequency (individual sympathetic and parasympathetic values). A stress value could be obtained by dividing these two values, which were projectedand plotted against time. Further, error analysis has been conducted, observing 12 categories of errors, including wrong phraseology, application of wrong ATC procedures, separation infringement, and loss of situational awareness. The experiment has shown that the students are prone to conduct mainly errors associated with basic procedures while with time and increasing workload, also errors connected to aircraft separation, situational awareness, and flight efficiency. The results indicate that the most common errors include failure to report aircraft/target identification, failure to confirm ATIS and QNH information for a given airport, descending below the transfer level, failure to respect airspace within vertical boundaries, loss of situational awareness or overall delayed response to the situation, or incorrect phraseology. This paper aims to assess student Air Traffic Controllers' psychophysiological state and performance during times of increased workload and provide an overview of physiological reactions and subsequent mistakes conducted by the trainees. Also, it should serve as an outlook of possible drawbacks that might have a negative impact on the initial training progress and should therefore be addressed with special care. Further, the experiment's results can be used for the adjustment of basic training where the most common types of errors occurring during increased workload can be addressed and trained within the enhanced practical part of the basic training.