Reliability prediction for self-repairing flight control systems

By using aerodynamically redundant control surfaces, a flight control system can be reconfigured in the event of an actuator failure and/or surface damage. This reliability feature is usually implemented through the use of some impairment detection, isolation and accommodation (IDIA) schemes. A case study is presented for a self-repairing flight control system (SRFCS), for which the probability of loss of control is computed under varying levels of hardware redundancy and varying values of IDIA coverage. Given the conditions peculiar to surface damage and control reconfiguration requirements in our application, a simple formula for obtaining accurate reliability predictions without employing Markov chain models is derived. As a result of the study, we are able to recommend how much performance improvement is needed in designing the SRFCS, and where the hardware redundancy level can be further reduced