A large part of BMP-2 Infantry Fighting Vehicles needs to replace turret ball bearing rings. Under realization of replacement of spare parts and components made in Russia with domestic ones, KNVO "Fort" MVO Ministry of Internal Affairs of Ukraine made an experimental batch of balls for turret ball bearing rings of infantry fighting vehicles BMP type. As a result of modernization of a turret ball bearing ring, steel balls were replaced with balls made of composite material. A turret ball bearing is a large radial thrust bearing, cages of which are turret races. A stabile lower race is fixed by means of screws to a top of the vehicle‟s hull. Above the fixed race there is a movable upper race to which the turret is bolted. A method for assessing the reliability of turret ball bearing rings of military armored vehicles was developed. The results of tests of turret ball bearing rings of BMP-2 infantry fighting vehicle tower are given. The reliability of turret ball bearing rings of armored vehicles was assessed taking into account the damage to the balls. The main types of damage to the balls: non-compliance of balls average diameter and non-compliance of the spherical shape of the ball to the requirements of operating documentation. The impact of the probability of no-failure operation of the balls on the durability of the ball bearing is determined. It is necessary to take into account the presence of damage to the balls when determining the durability of the ball bearing. To validate the adequacy of the method, it is necessary to increase the test time of the ball bearing by conducting tests during its operation.

The most important characteristics of the processes efficiency in aircraft equipment technical operation are the operational reliability characteristics. High reliability of aviation equipment is the main condition for its readiness, efficiency and safety. The aircraft equipment reliability is its ability to perform specified functions, maintaining during some time the values of the established flight and technical and operational indicators within the specified limits, which correspond to the specified modes and conditions of use, maintenance, repair, storage and transportation. Despite the quick scientific and technological progress in aviation, the problem of flights safety has become extremely acute in the present time. Empirical data statistical processing is an urgent task in monitoring of the Ukrainian Armed Forces aircrafts operation and determining trends in maintenance and repair, areas of modernization of armaments and military equipment. The subject of the work is the analysis and system approach based on the developed estimation technique of aviation equipment reliability indicators. The results of determined helicopters and their functional systems reliability are presented. The trend and the main reasons for the change in reliability indicators for 2016-2019 are determined. The main purpose of reliability analysis is to determine the causal relationships between quantitative and qualitative reliability indicators and the level of flight safety that lead to aviation accidents. Statistical information in the form of fault records and reports, where the generalized operational data are sent by the State aviation units according to the methodical recommendations. Indicators analysis of operational reliability and flights safety for helicopters according to statistical data of failures, damages and incidents is done. Moreover, the trend and the main reasons for the helicopters reliability indicators changes for the period 2016-2019 are defined. The results of research are presented in the final tables, which show the average values of operational reliability, flight safety and the level of combat flight task for different types of helicopters in all specialties. The causes of malfunctions that affect the level of operational reliability, flight safety and non-fulfillment of the flight task on helicopters for the period 2015-2019 were taken into account. According to the statistics analysis of the malfunctions reported causes , it is determined that the total number of reported malfunctions on different types of helicopters in 2019 increased by 11.0% compared to 2018, compared to 2017 by 43.7%, compared to 2016 by 58.4%, compared to 2015 by 70.0%.

The aim of the study is to develop and determine the maximum acceptable reliability factor of state aviation helicopters based on statistics on malfunctions that occur during the operation of the aviation materiel, taking into account the recommendations of ICAO. The paper defines the general criteria for calculating the limit values of reliability (operational reliability and flight safety). For their implementation it is necessary: to carry out constant monitoring of flight safety and the general reasons which cause emergence of malfunctions of helicopters, their systems and subsystems; to use the proposed combined model on the principle of "traffic light" to determine the level of flight safety indicators at their standard deviation when justifying decisions on the forecast for future periods of operation and establishing certain values of forecast indicators of the "upper control limit" of operational Based on the adopted conceptual approach to determining the dynamics of change in failure rates, quantitative criteria are developed. Proposals to determine the indicators of the technical condition during the military operation of the aircraft will maintain high combat readiness of state aviation at a given level, predict the need for maintenance and repair and predict the timing and direction of modernization of aircraft.