Category: Theory and definitions
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What is PM?
PM is a general term that encompasses all forms of pro-active maintenance including: scheduled overhaul scheduled inspections (CBM) CBM is the prominent form of maintenance today. Although all scheduled activities are called “PM” (for example, in the CMMS or EAM), they are predominantly CBM activities (inspections) performed, often, at the same time as scheduled service…
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RCM vs RA
Is RCM a form of Reliability Analysis (RA)? RA is the counting of failure and suspension events in order to understand the behavior pattern of a component or failure mode. RCM practitioners sometimes refer to the Reliability Centered Maintenance (RCM) process as “reliability analysis”. However, this is confusing. RCM Analysis (as opposed to RA), precisely…
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Purpose of RA
The purpose of reliability analysis (RA) is to build, assess the performance of, and continually improve maintenance policies. By a “maintenance policy” we mean a rule or process to be used for decision support. Why do we need policies? We need them because it would be inefficient to always have to evaluate repetitive maintenance situations…
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TBM or CBM?
In a fleet of over one hundred units there are four spare engines. Should an age based overhaul policy be used? Scheduling overhaul based on age seems appropriate due to the need to level the load in the engine rebuild shop. Given the expected failure rate, a rebuild interval of, say 10000 hours, and a…
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LRCM and the Failure Finding Interval
Safety devices represent one of the most important issues requiring serious attention by maintenance personnel. As a rule, when they fail, they fail silently and invisibly, with potentially disastrous results. Hence, the question facing reliability engineers is “How often should the safety device be tested for functionality?” That is, what is the “Failure Finding Interval”…