Despite considerable number of publications on methodology of Reliability Centered Maintenance (RCM), often there are difficulties with its understanding and use. The short description of an RCM essence according to the SAE JA 1011:2009 is given. For decrease in labor input of RCM approach according to which it is necessary to begin RCM with prioritization of the equipment is presented. The prioritization technique based on assessment of risk of refusal with use of recommendations of the IEC 60812:2006 is described. It includes consecutive prioritization of units, systems and components, and comes to an end with identification of critical knots concerning which the full RCM analysis is carried out. At the same time less critical components, systems and units can be subjected to repeated prioritization and the RCM analysis after reduction of risk of refusal of the most critical components. Following to this technique will allow to concentrate resources on the most critical equipment and to begin to carry out RCM analysis stages in the most effective way.