## 3 Results
### Step 3: Identify Unsafe Control Actions  
In the system structure, it's crucial to recognize that certain control actions can lead to hazardous system states. These situations are classified as UCAs and can be categorized into four main types:  
1. Necessary control actions for safety are not taken or properly followed (occurring when required actions are omitted or ignored)
2. Control actions are taken when not needed (meaning controls are applied at inappropriate times)
3. Potentially safe control actions are taken too late, too early, or not in the correct sequence (happening when timing or sequence is incorrect)
4. Safe control actions are stopped too soon or continue for too long (problems with continuous or discontinuous control actions). The analysis results of these unsafe control actions are presented in Table 4. The next step is to specify the controller actions that must be fulfilled to prevent the derived UCAs. Once the UCAs are identified, they can be transformed into constraints on the actions of each controller. Generally, each UCA can be inverted to define the constraints for each controller. * CC1-N-1: Ensure that the GCS Administration Module always has the capability to provide GCS control. [UCA1-N-1]
* CC1-P-1: Implement validation and verification checks to ensure that the GCS control provided is correct. [UCA1-P-1]
* CC1-T-1: Establish timely responsiveness in the GCS control provision process to prevent delays. [UCA1-T-1]
* CC2-N-1: Ensure GCS always has the capability to provide UAV Flight Commands. [UCA2-N-1]
* CC2-P-1: Implement validation and error checking in the UAV Flight Command issuance process. [UCA2-P-1]  
Figure 4: Hierarchical control structure of the system. CC2-P-2: Disable UAV Flight Command capabilities during abort/return flight unless specifically required under safe conditions. [UCA2-P-2]
* CC2-T-1: Implement real-time monitoring and alerts to ensure timely command delivery. [UCA2-T-1]
* CC3-N-1: Ensure ACM always provides necessary UAV direction and speed controls. [UCA3-N-1]
* CC3-P-1: Validate and calibrate UAV direction and speed controls to prevent incorrect control actions during flights. [UCA3-P-1]
* CC3-P-2: Prevent the ACM from altering UAV direction and speed during abort/return flight unless necessary. [UCA3-P-2]
* CC3-T-1: Ensure ACM controls are responsive and timely during active flights. [UCA3-T-1]
* CC3-D-1: Ensure ACM does not cease control prematurely and maintains functionality until the safe completion of the flight. [UCA3-D-1]
* CC4-N-1: Ensure GCS is always capable of issuing Danger Situation Alerts during emergencies. [UCA4-N-1]
* CC4-P-1: Validate the correctness of Danger Situation Alerts commands to ensure they are appropriate for the actual emergency situations. [UCA4-P-1]
* CC4-P-2: Implement checks to prevent the issuance of Danger Situation Alerts when no emergency is present. [UCA4-P-2]
* CC4-P-3: Introduce lifecycle management for speaker components with proactive replacements. [UCA4-P-3]
* CC4-T-1: Ensure timely delivery of Danger Situation Alerts to prevent late responses in emergencies. [UCA4-T-1]
* CC4-D-1: Configure GCS to cease Danger Situation Alerts once an emergency is adequately resolved. [UCA4-D-1]
* CC4-D-2: Ensure that Danger Situation Alerts are not discontinued prematurely during ongoing emergencies. [UCA4-D-2]
* CC5-N-1: Ensure that OMS is always capable of reporting dangerous situations. [UCA5-N-1]
* CC5-P-1: Implement accuracy checks in the reporting mechanism to ensure correct reporting of dangerous situations. [UCA5-P-1]
* CC5-T-1: Enhance the timeliness of the OMS's danger reporting system to ensure prompt alerts. [UCA5-T-1]
* CC6-D-1: Set appropriate limits on the duration of the CCTV video requested by the OMS to avoid excessive demands. [UCA6-D-1]  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \begin{tabular}{c} **Control Actions** \\ **(Controller/Controlled Process)** \\ \end{tabular}  & \multicolumn{3}{c}{**Not Providing (N)**} & \begin{tabular}{c} **Providing Causes** \\ **Hazard (P)** \\ \end{tabular}  &