Assessing the technical condition of equipment is an important task for ensuring operational strategy and planning maintenance work at an enterprise. One approach to evaluating equipment condition is the use of a well-known indicator called the 'technical condition index,' the calculation methodology for which has been approved by the Ministry of Energy of the Russian Federation. This methodology also proposes a scale for assessing the level of equipment technical condition. However, the question of the threshold or critical value of this indicator, which can determine the equipment's unsuitability for further operation, remains unresolved. This paper proposes a methodology for determining the threshold value of a modified technical condition index based on the allowable probability of failure-free operation of equipment using statistical methods. The novelty of the work lies in the proposed methodology for determining the threshold value of a modified technical condition index, developed by the author, which uses objective data for evaluation, unlike the subjective assessments of experts in existing methodologies. The proposed method was tested on a set of statistical data on the degradation of turbofan engines from NASA.

Keywords: technical condition index, modified technical condition index, threshold value, probability of equipment failure-free operation, complex technical object

Assessment of the technical condition (hereinafter TC) of technical systems is a prerequisite for a modern strategy for their operation. The study of new methods and algorithms that provide express assessments of the condition of technical devices and reduce the subjective component in these assessments is an urgent and in demand task. The paper presents a constructive approach to assessing the TC indicators of complex technical systems based on a modified method of analyzing hierarchies and the TC index (hereinafter referred to as ITS) of equipment, which is determined on the basis of weights and ITS of the main components of the equipment in question. The ITS of the main nodes is calculated based on the comparative characteristics of the operating parameters of the equipment during its operation, and the weights of the nodes are determined based on the methods of the matrix of paired comparisons (Saaty method) and the degree of importance of the line (DIL - Degree Importance Line method). The testing of the methodology and algorithms in this study was carried out on the basis of statistical data from a NASA turbojet engine (hereinafter referred to as turbofan engine), published in 2008.

Keywords: technical condition, technical condition index, complex technical system, maintenance and repair, hierarchy analysis method, DIL method, constructive method for assessing technical condition, algorithm for express assessment of technical condition