Aside from their form factor, the performance of these vehicles will dictate the layout and scale of landing areas (vertiports) along with the design standards for facilities that support eVTOL vehicle operations. Vehicle designers face challenges in the following four areas that will influence the feasibility of AAM:
Range: Most eVTOL vehicles have a range of just 20-30 miles (33-50 Km), while there are some designers suggesting that their vehicles have a range as high as 130-180 miles (215-300 Km); their claims have not been fully demonstrated. Storage capacity and efficiency of current batteries drive range limits. For these reasons, several designers are exploring hybrid fueling alternatives, such as using a mix of batteries and conventional or hydrogen fuel. Hybrid fueling has the potential to substantially increase the range up to 400-500 miles (660 -830 Km).
Battery Charging Rates: Even with current rapid charging technology, which could result in an 80% charge in 20-30 minutes, this rate still limits the number of times a vehicle can fly per day and its range on each flight. Other options, such as swapping batteries, have their challenges. Vertiports must have separate spaces and provide equipment to change and charge batteries.
Capacity: Current designs for eVTOLs indicate a carrying capacity of anywhere from 4 to 8 passengers, which effectively limits their usage to provide a faster alternative to the car. If autonomously operated, the capacity of the vehicle could be increased with the removal of the pilot and associated cockpit avionics. However, many in the industry believe that customers will not easily accept autonomous operations and will insist on having a pilot, even if most of the vehicle operation is automated. In addition to the capacity of the vehicle and the vertiport including the number of landing, pads will also be a major factor. The number of pads might be limited by the site conditions and/or cost.
All-Weather Operations: eVTOL vehicles will initially operate under visual flight rules (VFR) or “see and avoid.” This will result in a grounding of eVTOL vehicles in instrument meteorological conditions (IMC) or bad weather. As these vehicles become more automated and operators gain experience, eVTOL vehicles should be able to operate under instrument flight rules (IFR) similarly to equipped helicopter flights of today.
When combined, the aforementioned issues will impact the level of service that the operators will be able to offer. If capacity is limited to up to 8 persons then aircraft ground times will have to be short, meaning battery recharge times of 20-30 minutes will not be acceptable. Also, as service frequency increases, the need for additional Vertiports sites needs to be explored, as queuing of aircraft will not likely be possible, especially in the urban context. If aircraft only have a short-range, then intraregional travel will be limited to only short trips, such as airport to the city center; eVTOL vehicles will not serve inter-regional markets.
While addressing these technological challenges will not be easy, most agree they are not insurmountable and will not be the main obstacles to the success of AAM services.