## 4 Capacity Analysis for Each Topology
### Application to Three Kinds of Topologies  
The number of arrivals and departures of aircraft is the most important factor for analyzing throughput of a vertiport. Therefore, TLOF pad utilization is prior criteria for an efficient layout, and gate utilization should be considered when similar TLOF pad utilizations are given. Although the taxiways connecting the TLOF pad and the gate have different lengths, in this study, all taxiing times were assumed to be 15 s. In addition, the capacity of each vertiport was calculated for 15 min initially, and converted for one hour of operation to have the highest efficiency so that the analysis data can be easily interpreted. Segment time spending for one TLOF pad and four gates was explained in Table 5.  
An example of a vertiport composed of one TLOF pad and four gates with an empty vertiport was analyzed as shown in Figure 26. This analysis shows the maximum capacity that performs the (7, 4) arrivals and departures or the (6, 5) arrivals and departures by  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Components** & \multicolumn{2}{c}{**Slope Design Categories**} \\ \hline Length of inner edge & Width of Safety Area & Width of Safety Area & Width of Safety Area \\ \hline Length & 3386 m & 245 m & 1220 m \\ \hline Slope & 4.5\% & 8\% & 12.5\% \\  & (1:22.2) & (1:12.5) & (1:8) \\ \hline \multirow{2}{*}{Transitional Surface Slope} & 50\% & 50\% & 50\% \\  & (1:2) & (1:2) & (1:2) \\ \hline Transitional Surface Height & 45 m & 45 m & 45 m \\ \hline \hline \end{tabular}
\end{table}
Table 4: Dimensions and slope of obstacle limitation surfaces for all visual FATOs [15].  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Variable** & **Meaning** \\ \hline \(C_{\mathit{llef}}\) & Capacity of TLOF pads \\ \hline \(C_{\mathit{gate}}\) & Capacity of gates \\ \hline \(C_{\mathit{texit}}\) & Capacity of taxiways \\ \hline \(N_{\mathit{llef}}\) & Number of TLOF pads of vertiport \\ \hline \(N_{\mathit{gate}}\) & Number of gates of vertiport \\ \hline \(N_{\mathit{arr}}(t,n)\) & Number of completed arrivals at \(n\)-th gate \\ \hline \(N_{\mathit{dep}}(t,n)\) & Number of completed departures at \(n\)-th gate \\ \hline \(N_{\mathit{texit}}(t)\) & Number of completed taxiing operation \\ \hline \(t_{\mathit{trad}}(t,\ n)\) & Turnaround time at \(n\)-th gate \\ \hline \(t_{\mathit{g-h}}(t,\ n)\) & Gate holding time at \(n\)-th gate \\ \hline \(T\) & Operation time \\ \hline \hline \end{tabular}
\end{table}
Table 3: Variables for capacity determination algorithm.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Time Spending** & **Time (s)** \\ \hline Arrival & 60 \\ Taxi-in & 15 \\ Turnaround & 300 \\ Taxi-out & 15 \\ Departure & 60 \\ \hline \hline \end{tabular}
\end{table}
Table 5: Segment time spending (one TLOF pad, four gates).  
applying the time duration of each section in Table 5 during a 15 min operation time. \(\bigcirc\) stands for arrival, \(\times\) stands for departure, \(\square\) stands for free-arrival, and * stands for max-throughput. If there is no *, the last generated \(\times\) becomes the unique max-throughput.  
For the S-A1 capable of carrying four passengers, this vertiport can accommodate 20 passengers during its 15 min operation time because it can perform five departures after six aircraft arrivals for max-throughput so it can accommodate 80 passengers per hour. Table 6 summarizes the results of this analysis.