Functional Safety standards distinguish between systematic and random failures. The definitions attempt to clarify how to categorize real failures. The standards also explain that random failures are included in probabilistic failure analysis and systematic failures require changes in operating procedures.
However, it is clear that all real failures may prevent a safety system from performing its safety protection. Therefore any field failure collection system must count all real failures until it is shown by new failure records that a change in a procedure is effective in eliminating a type of failure.
This webinar shows the results of a recent survey where respondents classified real failures. It will be shown that many failures classified as systematic would result in an unrealistically low failure rate and possibly dangerous designs.