V. V. Goryachkin - Dr. Sc. (Eng.), Professor, Chair of mathematics and computer science, Golitsynsky Boundary Institute. E-mail: goryachkinv.v@mail.ru

One of ways of increase of reliability of radio-electronic systems is scheduled preventive replacement of their accessories of elements. There are some options of a method of the solution of such task. The most preferable is the method of replacement of elements in process of development or in advance established resource. Operation on a resource is carried out only in relation to the elements known in literature as elements of "growing old" type at which failure rate is increasing function of time. The natural assumption that element replacement at refusal borrows always not less becomes, and, than its precautionary replacement, that is replacement of a serviceable element, but already developed the resource, as a rule, there is more than time. The task consists in that a choice of optimum term of obligatory replacement of an element on an operating time to minimize on the average costs of time of replacement of an element and to maximize probability of its no-failure operation during set time. As criterion of optimization the coefficient of operational readiness gets out. The order of the solution of a problem of calculation of optimum time of replacement of an element on an operating time for devices which at refusal of their details are subject to restoration is considered and continue to be operated. Such devices at refusals completely aren't replaced, and restored by replacement of the element which has refused them. If it is in use revealed that the average of refusals (vosstanovleniye) of each of considered devices in unit of time is increasing function of time, exists optimum (for example, on an availability quotient) the period of their replacement. Thus if restoration is carried out by adjustments, it is possible to consider that these adjustments are carried out in such volume which provides in essence a complete recovery of the device. At failure of the device (refusal of its separate details) partial restoration is made. The offered method of scheduled preventive replacement of completing elements of the equipment and the equipment of the radio-electronic systems, considering intensity of wear of completing elements of the equipment, allows to solve a problem of development of scientifically reasonable plan optimum on the period of their replacement.