# Causation Correlation Analysis of Aviation Accidents: A Knowledge Graph-Based Approach
## 3 Aviation Accident Case Research
### Analysis of ACAKG Model Results
#### 3.4.3 Correlation Analysis of Accident Causation Types  
The correlation of an accident causation type is categorized into the direct correlation type or the indirect correlation type, which indicates the strength of direct or indirect causal  
Figure 6: The type distribution proportions of aviation accident causation. (**1**) Active type distribution ratio. (**2**) Passive type distribution ratio. (**a1**) Ground phase. (**a2**) Ground phase. (**b1**) Take-off/landing phase. (**b2**) Take-off/landing phase. (**c1**) Level flight phase. (**c2**) Level flight phase. (**d1**) Maneuvering phase. (**d2**) Maneuvering phase.  
relationships between accident causation types at different flight phases, and it is calculated using Equations (12) and (13), respectively.  
Figure 7 shows the direct and indirect correlations for different types of accident causation. Figure 7a shows the direct and indirect correlations of accident causal types during the ground phase. Overall, the H-type and M-type causations have the highest direct accessibility, followed by higher direct accessibility between the H-type and E-type and the A-type and H-type causations, indicating a higher direct correlation between these types of accident causal factors, and there is higher indirect accessibility between the H-type and H-type, A-type and H-type, and H-type and A-type causations, indicating a higher indirect correlation between these types of accident causal factors. In addition, there is no direct or indirect accessibility of accident causal factors between the E-type and A-type, E-type and E-type, E-type and M-type, and M-type and H-type causations. The direct and indirect correlations of accident causation types in the take-off/landing phase and leveling phase are shown in Figure 7b,c, respectively. The high direct accessibility between the H-type and H-type, H-type and A-type, H-type and E-type, H-type and M-type, and A-type and H-type causations indicates that the direct correlation of accident causal factors is higher for these types, including the H-type and H-type, A-type and H-type, H-type and A-type, and H-type and E-type causations. The high indirect accessibility of the E-type and A-type causations indicates that the direct correlation of accident causal factors is higher for these types, and the H-type and M-type causations have a higher indirect accessibility, indicating a higher indirect correlation between these types of accident causal factors. Similarly, there is no direct or indirect accessibility of accident causal factors for the E-type and A-type, E-type and E-type, E-type and M-type, and H-type causations. Figure 7d shows the direct and indirect correlations of accident causal factor types for the maneuvering phase of the aircraft. For the maneuvering phase, the direct accessibility between the H-type and H-type and the H-type and M-type causations is high, indicating that these types of accident causal factors have high direct correlations with respect to the other types of factors, and the indirect accessibility between the H-type and H-type, A-type and H-type, H-type and A-type, H-type and E-type, and H-type and M-type causations is high. In addition, there is no direct or indirect correlation between the E-type and the other types of accident causal factors, nor is there with the M-type and H-type and M-type and A-type causations.  
Figure 7: Correlation types of accident causal factors. (**a**) Ground phase. (**b**) Take-off/landing phase. (**c**) Level flight phase. (**d**) Maneuvering phase.  
Exploring the accessibility among different types of accident causal factors helps us to understand the correlations among different types of accident causal factors both locally and holistically, which can help us to develop preventive strategies for aviation accidents.