CBM is carried out based on the results of condition monitoring techniques. In ideal CBM, we assume that any
failure that is generated by the gamma failure distribution is noticed earlier and treated at the time of failure as a
scheduled maintenance activity with PM costs. The timing of the failure is shown as point F in the P–F interval
(Moubray 1997). The P–F interval is a part of the degradation curve. It starts at a point where a potential failure can
be detected (P) and ends at a point when the failure occurs (F). The P–F interval in the model is set at 15 days. In
non-ideal CBM, an inaccurate failure prognosis can cause CM activities. For failures in CBM, the model assigns a
CM activity instead of a PM activity in 10% of the cases. This CM is then scheduled randomly within the P–F
interval.