## 2 Components of Vertiport  
### Vertiport Component Sizing  
Among UAM infrastructure operating in urban areas, a vertiport has a limited number of components because it cannot be allocated a large space like an existing airport or heliport. Vertiport components are composed of TLOF pads, gates, induction paths, and so forth. We investigated various arrangements of components by referencing studies from the literature from the FAA and EASA. The FAA announced that they are discussing with EASA and ICAO about the vertiport installation standards, such as the TLOF, FATO, and safety area based on the maximum aircraft dimensions. The controlling dimension (CD) is the longest distance between the two outermost opposite points on the aircraft (e.g., wingtip-to-wingtip, rotor tip-to-rotor tip, rotor tip-to-wingtip, or fuselage-to-rotor tip), measured on a level horizontal plane that includes all adjustable components extended to their maximum outboard deflection [14]. EASA [15] classifies VTOL-capable aircraft as an enhanced category, and the standards for these are described in SC-VTOL-01. EASA uses the term 'D-value' to define the limiting dimension. 'D' represents the diameter of the smallest circle that surrounds the VTOL aircraft projection and contains the radius of the rotation of the rotor on the horizontal plane when the aircraft is in takeoff and landing configuration. Basically, both the FAA and EASA classify VTOL aircraft as small helicopters with an MTOW of less than 3175 kg (7000 pounds), but regulations of the two agencies for the vertiport are described differently. Thus, in each section, we applied both regulations separately. In this study, to provide a sufficient margin (e.g., considering rotor pitch), the size of the vertiport components was determined based on the size of the Hyundai S-A1 diagonal length, which is classified as a large eVTOL aircraft. The rectangular projected area of the S-A1 is 15 m \(\times\) 10.7 m, so the 18.4 m diagonal length of the rectangle is designated as the CD. When determining the size of the vertiport TLOF pad, as shown in Figure 1, we used a circular TLOF pad made by the CD because a circular shaped pad could be more recognized by a pilot than a square or rectangular shape in an urban environment [10]. The TLOF pad is a load-bearing, generally paved area, on which the VTOL aircraft takes off and lands. According to the engineering brief (EB), the landing area design and geometry includes the TLOF, the FATO, and the safety area [14], as shown in Figure 2. In the FATO area, it should be clear with no penetrations or obstructions except for navigational aids that are fixed-by-function, which must be on frangible mounts. To prevent a short circuit or lighting strike, a concrete surface is recommended on elevated TLOFs. In the case of elevated heliports with reinforced concrete construction of TLOF/FATO, cases of autopilot and avionics failure have been reported in some types of helicopters due to the creation of a strong magnetic field in the reinforced concrete slab. This could be an issue for UAM with advanced avionics. The imaginary surfaces for heliports are applicable to vertiports and include the primary surface, approach, and transitional surfaces. In a vertiport, the primary surface is the FATO. Figure 1: Size of TLOF pad for S-A1. Figure 2: Vertipad size for S-A1 that comply with the FAA’s new regulations. A vertiport needs to be provided with at least one FATO. The minimum width of a FATO is at least two times the CD of the design helicopter but not less than 100 ft (30.5 m) VTOL aircraft [14]. At elevations above 1000 ft mean sea level (MSL), a longer FATO is required to provide an increased safety margin and greater operational flexibility [10]. The safety area extends outward on all sides of the FATO for a distance of at least one-half the CD and is not necessarily a solid [14].