# Human Factors Analysis of the Improved FRAM Method for Take-Off Quality Lateral Shift
## 4 Take-Off Model Construction
### STEP 2: Identify functional variability.
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Lateral Displacement** & **Function Changes** & **Safety Quality** \\
**Distance (m)** & **Function Changes** & **Safety Quality** \\ \hline \(2\geq\) dy \(>\) 0 & Good steering control & Good \\
6 \(\geq\) dy \(>\) 2 & There is a risk of deviation from & Qualified \\   dy \(>\) 6 & The risk of deviation is high & Unqualified \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Function changes in “F2: rudder” (1). \begin{table}
\begin{tabular}{c c c} \hline \hline
**Maximum Lateral** & **Function Changes** & **Safety Quality** \\
**Displacement Distance (m)** & **Function Changes** & **Safety Quality** \\ \hline \(3\geq\) dy \(>\) 0 & Good steering control & Good \\
7 \(\geq\) dy \(>\) 3 & There is a risk of deviation from & Qualified \\   dy \(>\) 7 & The risk of deviation is high & Unqualified \\ \hline \hline \end{tabular}
\end{table} 
Table 8: Functional changes in “F2: rudder” (2). \begin{table}
\begin{tabular}{c c c} \hline \hline
**Lateral Displacement** & **Function Changes** & **Safety Quality** \\
**Correction Frequency** & **Function Changes** & **Safety Quality** \\ \hline \(2\geq\) n \(>\) 0 & Good steering control & Good \\  & Normal direction operation, & \\
4 \(\geq\) n \(>\) 2 & within the range & Qualified \\  & Poor direction control and poor & \\ n \(>\) 4 & flying skills & Unqualified \\ \hline \hline \end{tabular}
\end{table} 
Table 9: Function changes in “F2: rudder” (3). position and lateral displacement break through the safety envelope, the corresponding upstream module releases the mutation. Then, we check the module of the upstream phase by using video playback or flight parameter interpretation. The security envelope is shown in Figure 7.  
**STEP 3: Focus on the connections and potential relationships between functions. **  
In order to accurately identify the resonance relationship between all functional modules, the aircraft take-off process was analyzed using simulation tests, and the take-off model was constructed. The parameters of the take-off taxiing-phase model based on the take-off taxiing model and the disturbance factor are shown in Table 10.  
In the study of lateral offset, Reference [24] used the Kolmogorov-Smirnov test to analyze the distribution model of the aircraft wheel trajectory's lateral offset data, and it was verified that the lateral distribution of the observed model's wheel trajectory is more in line with a skewed distribution [25], as shown in Figure 8. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Name/Variable** & **Value** & **Unit** \\ \hline Lateral displacement distance dy & N (0,7) & m \\ Transverse maximum & N (0,10) & m \\ displacement distance DX & N (0,8) & / \\ Lateral displacement frequency & N (0,8) & / \\ Brake release time & 0 & s \\ Airspeed & N (0, n) & s \\ Wind direction & N (\(-\)90,90) & \(\circ\) \\ Wind speed & N (0,10) & m/s \\ Take-off climb gradient & 3\% & m/s \\ Actual airport pressure & 1013.25 & hPa \\ Aircraft model & / & / \\ Take-off weight & 23 & t \\ Maximum thrust & 2 \(\times\) 12,500 & kgf \\ Wingspan area & 34 & m\({}^{2}\) \\ Departure point & (400, 2000) & m \\ Runway width & 45 & m \\ Runway friction coefficient & 0.005 & / \\ Lift coefficient & 0.89 & / \\ Resistance coefficient & 153.2 & / \\ \hline \hline \end{tabular}
\end{table} 
Table 10: Take-off model parameter settings. Figure 7: Security envelope. By referring to the lateral offset fitting model and using the skewness distribution to simulate take-off, the main reference data, such as the lateral offset distance, the maximum lateral offset amplitude of taxiing, the lateral displacement correction frequency, airspeed above the ground, the rate of climb and the pitch angle, are obtained. The take-off quality analysis for the lateral offset mainly focuses on the lateral offset distance, maximum lateral offset amplitude, and lateral displacement correction frequency.