Mode Criticality
The mode criticality indicates how crucial the failure mode is under a particular severity classification. This criticality value is calculated per MIL-STD-1629, Procedures for Performing a Failure Mode, Effects and Criticality Analysis. The equation for calculating mode criticality is:
Descriptions follow for the three terms:
• Mode Failure Rate is the number of occurrences of a specific failure mode over a time period. For more information, see Mode Failure Rate.
• Mode Operating Time is the duration of applicable mission phase(s), usually expressed in hours or number of operating cycles. For more information, see Mode Operating Time.
• Failure Effect Probability is the probability that the failure will occur.
Larger mode criticality values indicate more critical failure modes. The mode criticality uses the failure rate multiplier when it is shown. For Failure Effect Probability, you enter a probability value between 0 and 1. If you leave this field blank, a value of 1 is assumed.
The level of Failure Effect Probability is based on where it is inserted in the Project’s FMEA Design file.
• If this field is inserted in the effect level, and the selected structure allows multiple effects per mode or multiple effects per cause, the values for this field are summed for all effects for the mode.
• If this field is inserted in the cause level, and the selected structure allows multiple causes per mode or multiple causes per effect, the values for this field are summed for all causes for the mode.
If this field is not inserted in a data level in FMEA Design file, a value of 0 is assumed.