Design and Develop Human Factors-Driven Safe Altitude for eVTOLs Operation in Regional Air Mobility

Future regional air mobility (RAM) covers connections between different terrains of regions, providing commuting and logistics with convenience using electric vertical takeoff and landing aircrafts (eVTOLs). However, visual differences from special terrains, such as seas and oceans, bring risk of situational awareness (SA) loss and even lead pilots to be out of control and descend into water. Accident reports from above-water flight highlight the necessity of safe altitude design for future eVTOL-based transportation. Therefore, this study aimed to propose an above-water safe altitude design method according to SA levels of eVTOL pilots. Pilots’ SA levels from cross-sea flight on 500 ft, 1500 ft and 2500 ft were evaluated through Situation Awareness Global Assessment Technique (SAGAT) accepted as ground truth. Electroencephalograph (EEG) signals of pilots were recorded as well to reveal unique patterns associated with SAGAT results. The results showed that among the three flight altitudes, cruising on 1500 ft achieved the highest SAGAT score of 80%, which was determined as the SA-driven safe altitude. Power spectral density (PSD) from the combination of frequency bands (δ + β)/(α + γ) showed a significant correlation with SAGAT scores (P = 0.017 < 0.05), indicating the feasibility of a neuro-ergonomic SA measurement. Therefore, human factors-driven optimisation approach is expected to provide instructions to safe altitude design as well as low-altitude airspace design.