# Impacts of Flight Operations on the Risk of Runway Excursions
## 4 Operational Analysis of Crucial Stages
### Moment of Flare and Speed Brake On  
In the 737 Crew Procedures Operations Manual, it is stated that when the main wheels are approximately 20 feet from the runway, the pilot should begin flare and increase the pitch attitude by 2 degrees to 3 degrees. This will reduce the rate of descent of the aircraft. The moment of flare refers to the moment when the pilot adjusts the aircraft's attitude in preparation for touchdown. At the flare stage, the overall magnitude of control column and control wheel operations for Style 3 exceeds that of the other two styles, as indicated in Table 3. This demonstrates that Style 3 operations are influenced by the wind, necessitating significant adjustments to the aircraft's attitude through extensive manipulation. Under the influence of wind speed, the aircraft's roll angle is significantly affected.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline  & **Monitoring Indicators** & **Averages** &
\begin{tabular}{c} **Standard** \\ **Deviations** \\ \end{tabular} & **Standard Errors** \\ \hline \multirow{4}{*}{Style 1} & Maximum position of the control wheel & 13.23 deg & 11.29 & 0.41 \\  & Minimum position of the control wheel & \(-\)11.04 deg & 11.86 & 0.43 \\  & Wind speed & 6.89 kt & 3.82 & 0.14 \\ \hline \multirow{4}{*}{Style 2} & Maximum position of the control wheel & 12.23 deg & 10.78 & 0.32 \\  & Minimum position of the control wheel & \(-\)9.86 deg & 11.39 & 0.34 \\  & Wind speed & 5.92 kt & 3.34 & 0.10 \\ \hline \multirow{4}{*}{Style 3} & Maximum position of the control wheel & 14.12 deg & 14.03 & 0.96 \\  & Minimum position of the control wheel & \(-\)14.23 deg & 12.40 & 0.86 \\ \cline{1-1}  & Wind speed & 9.28 kt & 4.24 & 0.29 \\ \hline \hline \end{tabular}
\end{table}
Table 2: The moment of runway threshold.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline  & **Monitoring Indicators** & **Averages** & **Standard Deviations** & **Standard Errors** \\ \hline \multirow{4}{*}{Style 1} & Maximum position of the control wheel & 11.19 deg & 10.85 & 0.39 \\  & Minimum position of the control wheel & \(-\)8.15 deg & 11.17 & 0.40 \\  & Maximum position of the control column & 3.24 deg & 1.10 & 0.04 \\  & Minimum position of the control column & 1.35 deg & 1.14 & 0.04 \\  & Pitch & 2.78 deg & 0.65 & 0.02 \\  & Roll & 0.29 deg & 0.86 & 0.03 \\  & Wind speed & 6.25 deg & 3.56 & 0.13 \\ \hline \multirow{4}{*}{Style 2} & Maximum position of the control wheel & 10.26 deg & 10.48 & 0.32 \\  & Minimum position of the control wheel & \(-\)6.65 deg & 10.96 & 0.33 \\  & Maximum position of the control column & 3.01 deg & 1.09 & 0.03 \\  & Minimum position of the control column & 1.40 deg & 1.12 & 0.03 \\  & Pitch & 2.84 deg & 0.60 & 0.02 \\  & Roll & 0.18 deg & 0.87 & 0.03 \\  & Wind speed & 5.47 deg & 3.02 & 0.09 \\ \hline \multirow{4}{*}{Style 3} & Maximum position of the control wheel & 13.41 deg & 12.57 & 0.87 \\  & Minimum position of the control wheel & 11.35 deg & 12.49 & 0.86 \\ \cline{1-1}  & Maximum position of the control column & 3.38 deg & 1.36 & 0.09 \\ \cline{1-1}  & Minimum position of the control column & 1.06 deg & 1.34 & 0.09 \\ \cline{1-1}  & Pitch & 2.78 deg & 0.66 & 0.05 \\ \cline{1-1}  & Roll & 0.33 deg & 1.00 & 0.07 \\ \cline{1-1}  & Wind speed & 8.81 deg & 4.17 & 0.29 \\ \hline \hline \end{tabular}
\end{table}
Table 3: The moment of flare.  
When the speed brake is deployed, as shown in Table 4, the inertial vertical speed of Style 1 is the highest among the three styles, with the ground speed also being the highest and a relatively large pitch angle. This indicates that Style 1 maintains significant speed and attitude at this stage.