# A Study on Identification of Development Status of MASS Technologies and Directions of Improvement
## 5 Hazard Analysis for MASS  
Another important aspect of MASS development is to analyze various hazards of MASSs that can lead to major accidents. Unlike manned ships, autonomous ships are operated by autonomous navigation systems with or without remote control from the SCC, depending on the degree of autonomy, and this might influence the safety of autonomous ships in various ways. On the one hand, the implementation of autonomous navigation systems may improve the safety of autonomous ships because this can eliminate human errors that make up the greatest portion of maritime accidents. It is commonly accepted that human error contributes to approximately 80% of all types of ship accidents [57]. Especially for collision accidents, human error contributes up to 96% [58]. Therefore, it is expected that autonomous ships will have a reduced number of navigation-related accidents, like collisions or groundings, compared to conventionally manned ships [51]. On the other hand, autonomous navigation systems may adversely affect safety. The new technologies for autonomous navigation and increased complexity can introduce new hazards and cause unforeseen system interdependencies [59; 60]. It should also be considered that we currently have a large number of incidents that are prevented by human operators, which would be impossible for autonomous ships [61]. These relationships between autonomous ships and reduced/increased incidents are illustrated in Figure 3. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Systems** & & **Issues Identified** & **Items to Be Considered** \\ \hline Maintenance & \(\bullet\) & Reliable and redundant propulsion & \\  & and maneuvering systems & \(\bullet\) & Maintenance crews when a vessel is in port \\  & \(\bullet\) & Wider adoption of condition monitoring & \(\bullet\) & RCM and Risk-CM systems \\  & system with diagnostic & \(\bullet\) & Integrated modules for reliability of systems \\  & & and prognostic functions & \\ \hline Repair & \(\bullet\) & Repair systems for errors and malfunction in software & \(\bullet\) & Resilient and redundant systems for failures \\  & \(\bullet\) & Emergency system for firefighting, failure & \(\bullet\) & Automatic and/or remote system for repair \\  & \(\bullet\) & recovery, and repairs at sea & \(\bullet\) & Cargo related problems such as cargo shift, \\  & \(\bullet\) & system to make a ship return to a port & \(\bullet\) & leaks, moisture, fire and flooding \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Issues identified and items to be considered for the maintenance and repair of autonomous cargo ships. For safe operation of autonomous ships, analysis of new hazards of autonomous ships will be needed with the aim of preventing or mitigating the new incidents. We already have commonly used hazard analysis techniques, like failure mode and effect analysis (FMEA), hazard and operability (HAZOP) study, preliminary hazard analysis (PHA), and so on. FMEA was developed in the 1940s to identify problems in military systems, and FMEA is currently required to be integrated into the design process of technical systems in many industries such as defense, aerospace, oil and gas, automobile, and maritime industries. HAZOP was developed in 1963 for the chemical industry, and today, HAZOP has become a standard hazard analysis process for the design of offshore oil and gas platforms and used for hazard analysis in many different application areas [62]. However, there is an argument that these traditional methods developed in the 1940s and 1960s are not appropriate to analyze the hazards of modern, complex, and software-intensive systems like autonomous ships. [PERSON] [63] argued that these traditional methods are inadequate to analyze hazards of very complex systems because traditional methods mostly focus on failure events and the role of component failures, which are not the main causes of the accidents of modern complex systems.