In Condition-Based Maintenance (CBM) policy, the action taken after each inspection is dependent on the
state of the system. There could be no action or minimal action to make the system as good as it was before
degradation, or major maintenance to bring the system to a state as good as a new system. If a machine cannot
keep to a required tolerance, condition-based maintenance is initiated. This policy is based on deterministic and
probabilistic models. In this policy, conditioning monitoring is essential because it provides information about the
current state of system (Akturk and Gurel 2007). CBM also provides useful information for diagnoses and
prognoses about the root cause(s) and failure mechanisms of the damage (Grall et al. 2002, Marseguerra et al.
2002, Jamali et al. 2005).