Bridging Software and Hardware FMEA in Complex Systems

When complex software-controlled systems are subject to both software and hardware FMEA, conclusions are often incorrect in areas where software and hardware failures affect each other. These analysis errors occur because software specialists generally do not analyze hardware and hardware specialists generally do not analyze software, a situation that often leads them to use educated guesses when determining system-level effects in such crossovers. Sometimes a particular failure mode is assessed as part of hardware FMEA and a similar failure mode is independently assessed as part of software FMEA, causing duplication of effort and the strong possibility of two different conclusions. Fortunately, a structured approach to planning and execution of FMEA of complex software/hardware systems, with ground rules and guidelines focused on software/hardware crossover, can make the analysis more efficient, thorough and correct. The approach improves upon the traditional FMEA process.