Engagement Reliability Analysis Method of Electric Light Aircraft Based on Failure Mode Effects and Criticality Analysis

The reliability level of electric light aircraft is the core index to judge the flight safety level of this type of vehicle. As such, developing an objective measure to determine such reliability has been the focus of current research in the industry and the academia. In this study, a reliability analysis index system that includes four first_level indexes and 14 second-level indexes was constructed for electric light aircraft from the perspective of intrinsic safety. Based on failure mode effects and criticality analysis (FMECA), a table depicting the failure probability of the main components and elements of electric light aircraft and the subsequent effects was designed. Then, the hazard degree of key components was determined. Next, a calculation model for the criticality of electric light aircraft was established based on the failure probability and reliability function and the failure probability and distribution function. Finally, a fitting function based on probability distribution and criticality was constructed with a two-seater electric light aircraft as an example. The criticality of the electric light aircraft was calculated, and the overall reliability level of the aircraft was obtained. Results show that the key components of the electric light aircraft can be effectively identified based on FMECA theory. Furthermore, the criticality of the components is directly proportional to the own criticality and failure probability of the aircraft. The order of criticality of the application objects is as follows: electric motor, needle roller bearing, brake pump, relay, front torque arm, lithium battery, and front upper pillar. The obtained conclusion provides a theoretical reference for the design and reliability evaluation of electric light aircraft. Key Words: Electric light aircraft; failure mode and effects analysis; probability distribution function; key components; criticality