Summary
- EVTOLs have high velocities of downwash and outwash from rotorcraft operations, posing safety and environmental challenges
- The FAA tested three EVTOL prototypes for their downwash and outwash velocities, which exceeded safe levels
- EVTOL rotorwash velocities can reach hurricane-level speeds, causing significant damage to property and risking injury or death
- Vertiports need to establish Downwash Caution Areas to account for the horizontal outwash dispersion during VTOL operations
- EVTOL startups are facing challenges with certification costs, unrealistic business cases, and rotorwash velocities, leading to bankruptcies and program cancellations
Article
In the world of electric Vertical Takeoff and Landing (eVTOL) aircraft, the dreams of futuristic flying vehicles have been met with the cold reality of safety challenges. The Federal Aviation Administration (FAA) has identified concerns regarding the high-velocity downwash and outwash generated by rotorcraft operations, posing risks to personnel, infrastructure, and the environment. Traditional helicopters have strict guidelines to prevent dangerous velocities, but eVTOL aircraft present a new set of challenges due to their innovative designs.
The FAA recently conducted tests on three eVTOL prototypes to measure their downwash and outwash velocities. They found that these aircraft exceeded safe airflow thresholds, with velocities comparable to those of Category 1 and Category 2 hurricanes. The force exerted by high winds increases dramatically with velocity, presenting significant risks to property and individuals. These findings have major implications for the development and operation of eVTOL aircraft, particularly in urban areas where vertiports were being considered.
In response to the survey results, the FAA released Engineering Brief No. 105A, providing supplemental guidance for vertiport design to address the challenges posed by eVTOL rotorwash velocities. The brief introduces a new downwash caution area (DCA) requirement for vertiports, extending well beyond the final approach and takeoff area to mitigate horizontal outwash dispersion. Vertiport planning must now account for DCAs to ensure the safety of personnel and property during eVTOL operations.
The FAA’s findings have raised questions about the feasibility of eVTOL operations in cities and other locations due to safety and infrastructure concerns. The need for expanded vertiport size and setbacks, combined with the high costs of certification and uncertain commercial viability, suggest that many eVTOL startups may struggle to succeed in the long term. Recent bankruptcies and program cancellations in the industry indicate a challenging road ahead for eVTOL manufacturers.
As the EVTOL industry grapples with safety and certification challenges, the future of these innovative aircraft remains uncertain. With the high costs of compliance, limitations on flight paths, and risks associated with rotorwash velocities, the path to commercial success for eVTOL manufacturers is fraught with obstacles. Ultimately, the eVTOL space may face consolidation and closures as the industry navigates the complexities of certification, safety regulations, and economic viability.
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