Question 1

What RPN threshold requires action?

Accepted Answer

Traditional FMEA practice uses RPN > 100 or > 125 as action thresholds, but this approach has limitations — an RPN of 100 could be S=10, O=10, D=1 (very dangerous but detectable) or S=5, O=4, D=5 (moderate risk). The AIAG-VDA 2019 standard recommends evaluating S, O, D individually and using Action Priority (AP) tables instead of a single RPN cutoff.

Question 2

What is the difference between FMEA and FMECA?

Accepted Answer

FMEA identifies failure modes and their effects. FMECA (Failure Mode, Effects, and Criticality Analysis) adds a criticality analysis step that quantifies failure probability and severity in a more rigorous way using MIL-STD-1629A methodology. FMEA with RPN is more common in automotive/manufacturing; FMECA is used in aerospace, defense, and nuclear industries.