Failure modes effects test for flight control system

New generation aircraft requires high maneuverability and control performance which are made possible using advanced flight control technology based on the concept of the fly-by-wire (FBW). Included in the flight control technology is the verification and validation process for an advanced flight control system (FCS) employed in the new generation aircraft. The digital FCS requires various dedicated tests to ensure a high degree of the system reliability and flight safety. This paper deals with a failure modes effects test (FMET) for the digital FCS as a subset of the system test process. In this paper, the digital FCS and of its operational flight program (OFP) development procedure for the T-50 advanced trainer of the Republic of Korea Air Force (ROKAF) are first overviewed. The FMET process applied to the T-50 FCS including the evaluation criteria and its corresponding test procedure is presented. The basic ground rules for the FCS FMET procedure are finally obtained from the presented study. These rules can be used as a guide in the planning and conducting of the failure mode testing to ensure the high reliability and flight safety.