A simpler form of an FMECA is an FMEA (Failure Modes Effects Analysis). An FMEA does not consider how often a failure occurs, but only evaluates its effect and severity when it does occur. An FMECA evaluates both severity and probability of occurrence, and sometimes one additional parameter.

A Risk Profile Number (RPN) analysis always brings this additional parameter into the analysis.

1. Besides severity and probability of occurrence, what additional parameter does an RPN analysis consider?
2. Discuss why this additional parameter is important, especially in critical applications or missions.