4.2.9. Operator and Operation

While in Figure 9a, there is a spike for FSNCs, this is not statistically significant. In fact, if we compare to a previous study that investigated business models in HF accidents [28], the distribution of accidents with maintenance contributions has a similar shape, and hence with a limited sample size, this would also not produce a statistically significant result. For the type of operation or service, the result is statistically significant, with the peak value for domestic and the minimum value for charter responsible for this. It should be noted that ICAO indicates globally that 60% of revenue passenger kilometers are currently international [29], leaving 40% for domestic (including regional). However, we can clearly see that accidents with maintenance contributions are more likely to occur in domestic operations, so relative to traffic, this becomes even more significant.

**Figure 9.** Results for aviation aspect of the accidents with maintenance contributions: (**a**) the operators business model; (**b**) the type of operation/service.
