## 5 Qualitative Validation--Results and Analysis  
This section presents the results obtained from the simulation of the developed digital model of EMA (Figure 6) in conjunction with ABS and EBS. Primarily, comparison between different scenarios (mentioned in Section 4.1) and the corresponding impact of fault modes on the system performance is drawn. The 'Normal Operation' condition is used as the base scenario with the best overall performance.  
As can be seen in Figure 7, four key aircraft operation parameters, namely, Stopping Distance, Wheel Slip, Wheel Angular Speed, and the Vehicle Linear Speed are analysed against the EBS normal operation condition and the different fault modes. A significant impact is observable on all aircraft operation parameters with the introduction of faults, when compared with the 'Normal Condition' base scenario.  
Most significant is the impact of \"jamming,\" as it halts the braking function of the aircraft altogether. The OC fault mode is similar to jamming in a way that as soon the signal brakes, it stops braking. The IOC also shows a reduction in performance when compared with the normal condition scenario. It is important to note that the jamming presents very hazardous environment, which may result in the damage to the actuator and other equipment near the actuator. The wheel and the brake itself can suffer notable issues with possible severe consequences for the aircraft. Figure 8 shows the change in the motor temperature. It can be seen that jamming causes maximum increase in temperature as compared with other fault scenarios, which could potentially lead to a hazardous situation compromising the integrity of the actuator and other peripheral systems. As for the OC and IOC, the increase in temperature seems much less dangerous; nevertheless, it indicates an ongoing fault in the system.  
Similarly, the performance degradation trend is quite evident on the motor angular displacement and braking force, as shown in Figure 9. Again, jamming presents the maximum impact leaving the system with no force and angular displacement. OC stops abruptly as expected and IOC displays a considerable reduction in performance.  
Lastly, the impact of the fault modes on the power of electric motor can be noted in Figure 10, where the normal condition (a) is compared with all the three scenarios. As is evident, there is a great variation in the electric power of the motor, which eventually impacts the overall performance of EMA. The scenario with the OC (b) shows the abrupt cut in power that affects the motor of the actuator, with a clear disruption in the system. In case of the scenario with IOC (c) displayed, the power cuts after every cycle and power spikes when the connection is closed, reducing the performance of the EBS. The fourth scenario (d) shows the electric power increasing with time as the actuator is subjected to the jamming condition, generating other disruptions, such as rapid temperature increase and no actuator displacement.  
Figure 7: A comparative impact analysis of different fault modes with the Normal Operation conditionof EMA (**a**) Stopping Distance comparison; (**b**) Wheel Slip comparison; (**c**) Wheel Angular Speed comparison; (**d**) Vehicle Linear Speed comparison.  
Figure 8: The impact of fault modes on the temperature of the EMA.  
Figure 9: The impact of fault modes on motor angular displacement and braking force; (**a**) motor angular displacement; (**b**) braking force.