*1.3. Hypothesis and Obejctives of the Study*

To meet the objectives of the research line, tasks include a massive analysis of the data on neurophysiological variables so that correlation between their evolution over time and the ATC events that have taken place during the simulation can be defined. The aim is to establish general patterns and set limits on certain combinations of events so that the workload of ATCOs is within acceptable levels.

The starting hypotheses of the study are as follows:

**Hypothesis 1:** *It is possible to determine a taskload distribution profile based on data recorded in a control position that can serve as a reference for the subsequent analysis of the evolution of the neurophysiological variables of ATCOs*.

**Hypothesis 2:** *Based on a taskload distribution profile, variables related to subjective workload assessment can be used to establish whether this baseline profile is the best reference for the subsequent study of the evolution of neurophysiological variables*.

To test the hypotheses of this study, the development of a laboratory experiment with controlled ATC events, the use of an ATC simulator, and the development of a campaign of real-time simulations were chosen. Initially, when the exercises were designed, the starting point was a designed taskload profile. The research question to be answered now is whether this designed taskload is a good reference or whether it is necessary to define a more adequate taskload profile. Only by answering this question will it be possible to continue the study of events and the analysis of the combinations of events that induce a higher workload on the participants.

Additional information about the participants will be presented in later sections. The sample was selected in such a way that participants were as homogeneous as possible in relation to their age, training, and skills. In this first part of the research line, it was important to invest as many hours as possible in the simulator to obtain a robust methodology. For this reason, the chosen participants are ATCO students.

The study presented in this paper has two main objectives: (i) to establish a suitable taskload profile, which will serve as a reference for further studies in the project and determine whether the designed taskload profile can fulfil this function or whether it is necessary to define a new one; and (ii) once this reference is established, to study which events or combinations of events cause the most complex situations within the sector.

To the authors' knowledge, this study is original as it includes as taskload references a series of specific events to this line of research. Similarly, the methodology used and the process of analysing the data collected during the experiment are also novel.

Studies focused on the taskload and workload concepts sometimes present the important limitation of using the two terms interchangeably. In this paper, right from the introduction, the aim is to eliminate this limitation by clarifying the differences between the two concepts. In the same way, another risk that can arise from these studies focused on such specific topics is that they have a limited application and cannot be extrapolated to other research. To overcome this limitation, this study, in addition to generalising the methodology to other similar experiments, includes a series of recommendations when discussing the results obtained. These recommendations are intended to serve as a guide for applying the lessons learnt during this research to similar subsequent studies.

The remainder of this paper aims to present the steps that have been taken to achieve these objectives. The structure is as follows. In Section 2, Materials and Methods, the steps followed in the study are presented, as well as some details on the development of the simulations and the data recorded. Section 3 presents the results obtained after the simulations were carried out by the six participants. Section 4 presents two subsections. In the first, the results are explained using a case study of one of the participants and the key findings are identified. The second subsection presents some recommendations for future research based on the lessons learnt in this study. Finally, Section 5 summarises the results obtained and the next steps to be taken within the line of research.

### **2. Materials and Methods**

Before discussing the results obtained, it is necessary to present the methodology followed to achieve them. This section includes general information on the methodology followed in the first subsection, as well as some details on the events considered in the design of the simulations, useful information on the simulations carried out, and an explanation of the data recorded, respectively, in the following subsections.
