  Fault tree analysis is a technique widely used in risk and reliability
analysis of complex engineering systems given its deductive nature and
relatively simple interpretation. In a fault tree, events are usually
represented by a binary variable that indicates whether an event occurs or not,
traditionally associated with the values 1 and 0, respectively. Different
events are linked together using logical gates, modelling the dependencies that
a subsystem or system may have over its basic components. In this study,
quantum computing is leveraged to propose a novel approach to encode a
traditional fault tree into a quantum algorithm. This quantum fault tree method
uses quantum bits to represent basic events, effectively encoding the original
fault tree into a quantum circuit. The execution of the resulting quantum
circuit represents a full simulation of the fault tree, and multiple executions
can be utilized to compute the failure probability of the whole system. The
proposed approach is tested on a case study portraying a dynamic positioning
system. Results verify that the quantum-based proposed approach is able to
effectively obtain the dynamic positioning failure probability through
simulation, opening promising opportunities for future investigations in the
area.
