## 2 Materials and Methods
### Dependent Measures  
The final approach performance was assessed in terms of deviation, self-assessment of the deviations, and the approach quality. The approach quality was calculated as an objective score based on recorded kinematic data of the simulator. Kinematic data (e.g., altitude, speed, direction) were recorded for all test and training flights during the experiment. When deviation of airspeed and estimated touchdown point exceeded a certain threshold, a cumulative penalty was calculated during the approach. The approach quality was calculated by subtracting the penalty from the initial value of 100 (excellent approach). Therefore, the lower limit of the approach quality score was 0 (extremely poor approach). In addition, an objective deviation score was calculated for each approach scenario by using kinematic data of the simulator. One point for each type of deviation: too fast, too slow, too short, and too far. Lower objective deviation scores reflect better performance. The self-assessment of the deviations was calculated for each scenario as the sum of correct answers received from the trainee. Therefore, a higher self-assessment score reflects superior situation awareness/performance because this is required in the associative stage of skill acquisition [34]. For the statistical analysis, final pre-test and post-test scores were calculated by adding the values obtained for each of the three approach scenarios per test. Trainees' situation awareness was self-rated after each test using the Situation Awareness Rating Technique (SART) [38], with item scales ranging from 1 (low) to 7 (high). The final subjective score of SART was used, as well as the scores of the subscales: demands on attention resources, supply of attention resources, and understanding of the situa \begin{table}
\begin{tabular}{l l l l} \hline \hline
**Phase** & **Content** & **Experimental Group** & **Control Group** \\ \hline \multirow{2}{*}{Introduction} & Briefing & \multicolumn{2}{c}{written instructions} \\ \cline{2-4}  & Familiarization & \multicolumn{2}{c}{with simulator} \\ \hline Pre-test & \multirow{2}{*}{Approach maneuvers} & \multicolumn{2}{c}{in the simulator without AR} \\ \cline{2-4}  & & & \\ \cline{2-4}  & & & \\ \cline{2-4}  & & & \\ \hline Training 1 & Familiarization & \multicolumn{2}{c}{with HoloLens and the AR application} & — \\ \cline{2-4}  & Approach training in the simulator & \multicolumn{2}{c}{six with AR and six without AR} & 12 without AR \\ \cline{2-4}  & Self-evaluation and feedback & \multicolumn{2}{c}{with AR} & with pen and paper \\ \hline \hline \multicolumn{4}{c}{Break} \\ \cline{2-4}  & Training 2 & \multicolumn{2}{c}{Approach training in the simulator} & \multicolumn{2}{c}{six with AR and six without AR} & 12 without AR \\ \cline{2-4}  & & & \\ \cline{2-4}  & Self evaluation and feedback & \multicolumn{2}{c}{with AR} & with pen and paper \\ \hline Post-test & \multicolumn{2}{c}{} & \multicolumn{2}{c}{in the simulator without AR} \\ \cline{2-4}  & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Procedure for the experimental and control group. tion. Workload was self-assessed using the Task Load Index (NASA-TLX) [39] containing six dimensions: mental demand, physical demand, and temporal demand of the task, effort, performance, and frustration. The NASA-TLX scales ranged from 1 (very low) to 7 (very high). In order to calculate the total workload score, the performance scale was inverted. After each test, the trainees self-rated the emotions experienced during the test using the Positive and Negative Affect Schedule (PANAS) [40]. In PANAS, the item scales ranged from 1 (very slightly or not at all) to 6 (extremely). Motivation was self-assessed by the trainees after each test using the Questionnaire on Current Motivation (QCM) [41] consisting of 18 items measuring four factors: challenge, interest, probability of success, and anxiety/fear of failure. Each QCM item had a scale ranging from 1 (disagree) to 7 (agree).