Controllability-involved risk assessment model for carrier-landing of aircraft

Are the risk levels of many mishaps (which include the carrier-landing mishap) directly related to the time available to correct the abnormal system state? In the case studies of past mishaps, it can be seen that the landing mishaps of carrier aircraft are often caused by the reason that the time available to control the aircraft or adjust its flight attitude is not sufficient. Moreover, engineering experience intuitively tells us that as the time available to take corrective action over a hazardous situation increases, the ability to exert controls and avoid mishap also increases. However, there is no evidence to prove this conclusion yet. We focused on risk controllability, and presented a certain variable “Time Margin”(T_m) which could characterize risk controllability as possible. Moreover, we established a conceptual model of risk, including the variable characterizing risk controllability, based on conventional risk assessment model which includes variables mishap probability and mishap severity. By using the carrier-landing process as a case, with the statistical data from real samples on carrier-landing performed aboard the USS Enterprise CVN-65, we implemented an empirical research program into the relationship between ability to correct landing attitude and mishap risk, to verify the rationality of the improved risk assessment model. The law of the relationship between T_m (the time available for the pilot to adjust the flight attitude and glide slope) and the risk reflected by the actual record data has been revealed. Statistical analysis shows that: Both the probability and the severity of landing mishaps are negatively correlated with T_m. In other words, it´s concluded that the risk is negatively correlated with the T_m. The sample size of aircraft landing is large, and the data are derived from actual record, therefore the conclusion is authentic and credible. It illustrates the argument that t- e more sufficient the time available to correct the hazardous situation is, the greater the chance of controlling or avoiding mishaps is.