Assessment of Health Monitoring Trustworthiness of Avionics Systems

Vladimir Ulansky,Iryna Terentyeva,Igor Machalin

doi:10.36001/ijphm.2021.v12i2.2907

Abstract

The article provides a methodology for assessing the trustworthiness of health monitoring the dismounted avionics systems with automated test equipment (ATE). The indicators include the probabilities of false-positive, false-negative, true-positive, and true-negative. For the first time, we introduced into consideration the instability of the source of stimulus signal (SSS), the random and systematic component of the measuring channel error, and the reliability characteristics of the systems themselves. We consider a specific case of an exponential distribution of permanent failures and intermittent faults and derive formulas for calculating the trustworthiness indicators. Numerical calculations illustrate how the probabilities of correct and incorrect decisions depend on accuracy parameters. We show that the probabilities of false-positive and false-negative increase much faster than the probabilities of true-positive and true-negative decrease when the standard deviation of stimulus signal increases. For a Very High-Frequency Omni-Directional Range (VOR) receiver, we demonstrate that even with a zero random error generated by the source of the stimulus signal, the probabilities of false-positive and false-negative are different from zero.

Highlights

Many airlines and air-force bases worldwide use automated test equipment (ATE) for monitoring and diagnostics of avionics systems
This paper has developed a new mathematical model for assessing the trustworthiness indicators of health monitoring the dismounted avionics systems, which include the probabilities of false-positive, false-negative, true-positive, and true-negative
We considered the case of an exponential distribution of permanent failures and intermittent faults; we derived formulas for calculating the trustworthiness indicators since usually there is statistical information for this distribution

Summary

INTRODUCTION

Many airlines and air-force bases worldwide use ATE for monitoring and diagnostics of avionics systems. At the stages of the design and operation of ATE for avionics systems, the task of assessing the trustworthiness indicators of health monitoring is highly topical. Inspection errors such as false-positive and false-negative can lead to economic losses and flight safety reduction. As is well known (Raza, 2018; Raza & Ulansky, 2020), any two or three-level maintenance options must check the operability of the dismantled LRU or LRM. Since the flow of dismounted LRU includes both inoperable and operable units, one of four incompatible events may occur according to the checking results: true-positive, falsepositive, true-negative, or false-negative. We consider an example of assessing the trustworthiness indicators when testing ILS with ATE

Block Diagram of VOR Receiver Health Monitoring

Determination of Probabilities of Correct and Incorrect Decisions

Case of Sudden Failures

RESULTS AND DISCUSSION

CONCLUSION