Reliability Analysis of Flight Control System under Perfect and Imperfect Fault Coverage

Systems such as aircraft control need very high levels of reliability, so redundancy is adopted for acquiring the same. The reliability of the system gets affected due to the coverage. When a component in a system fails, the detection and isolation of the system are less than perfect. This is called as coverage. Fault Coverage Model is of two types, Perfect Fault Coverage Mode (PFCM) and Imperfect Fault Coverage Mode (IFCM). In PFCM, coverage is perfect i.e. its value is unity while in IFCM, coverage is not perfect i.e. it can take any value other than unity. Flight Control System (FCS) also falls under this category. FCS consists of sensor, computer, actuator and two communication channel. In this paper, three different configurations of FCS are considered in terms of Redundancy Corporation. For all the three systems, reliability indices for both PFCM and IFCM have been calculated by considering communication channel as perfect and imperfect. It has been observed that IFCM reliability is less than PFCM, hence IFCM depicts true system. Then, some comparisons have been done among the reliability of three systems under perfect/imperfect fault coverage by taking communication system as perfect and imperfect. Hence, out of these three systems best one is pointed out.