Urban Air Mobility Operations: Evaluating Exposure to Lightning Strikes

The escalating demand for innovative modes of commuting within sprawling urban conglomerations has spurred the necessity for new transportation services. Predominantly utilizing electric Vertical Takeoff and Landing (eVTOL) technology, Urban Air Mobility (UAM) envisages operations at lower altitudes and speeds, facilitating connectivity between vertiports across cities or acting as shuttles linking various points within airports. UAM is subjected to rigorous regulatory scrutiny, reflecting the innovative characteristics inherent in its design. An important concern in regulatory considerations is the effect of the atmospheric electric environment on UAM operations. Notably, the eVTOL requires a lightweight design to meet operational viability, constrained by the weight limitations imposed by its electric motors. Using primarily composite materials for its construction results in a lighter structure, albeit offering a distinct level of lightning protection compared to metallic structures. Given the multiple challenges and complexities inherent in its operation, understanding the electrical environment where the eVTOL will operate in cities is of great value. In urban areas, aerosols and heat islands enhance lightning activity by intensifying the severity of thunderstorms. Therefore, the trajectory of UAM flights will require navigating around cumulonimbus clouds and associated convective structures, which pose a significant risk of lightning incidence and strong wind gusts. Based on these considerations, this work investigates how urban atmospheric environments affect the operation of eVTOLs by analyzing lightning strike probabilities in dense cityscapes. Through a literature review and theoretical frameworks, the study examines the regulatory landscape, technological constraints, and environmental characteristics to assess this critical aspect of UAM safety and contribute to the ongoing discussion on UAM, specifically concerning lightning exposure and possible strategies to mitigate incidents and/or accidents.