Modelling the Quality of Inspections by Maintenance Service Providers Based on an Opportunistic Inspection and Replacement Policy

Maintenance contracts require outsourcing as a key element. However, the quality of the maintenance service providers’ actions is crucial. In inspection maintenance, misclassifications are common and may fail to prevent accidents or lead to unnecessary actions. On the other hand, high-quality suppliers require a substantial amount of investment. To deal with this dilemma, we came up with a hybrid inspection policy model that aids in picking a suitable supplier for maintaining a single-component system. The term “hybrid” is used to describe the combination of opportunistic inspections (i.e., random) and preventive replacement. Short intervals of opportunities could result in frequent and unnecessary replacements. In contrast, opportunities that occur over a long period may not be utilized for timely replacement. Therefore, a component age threshold (MΔ) is set so that only opportunities arising after this point are considered. This ensures that the replacement, originally planned for KΔ, is anticipated to coincide with the opportunity’s arrival, provided that the component is still functioning when the opportunity arises (after MΔ). This proposal extends inspection models based on the delay-time concept and opportunistic actions. The cost-rate and mean time between operational failures (MTBOF) are used to evaluate the performance of this policy. The effectiveness of it in assessing the quality of third-party inspectors has been proven. In general, our findings show that investing in higher-quality suppliers is worth it.