Failure Modes and Effects Analysis (FMEA)

Skill level: Advanced

Description

Failure modes and effects analysis (FMEA) is a technique that systematically analyzes a system, subsystem, or process for potential failure modes. This detailed examination of a process can be done at any level down to the smallest component or action.

During an FMEA, you determine a risk priority number (RPN), which is a multiplication of the severity of a failure, how often the failure occurs, how often the failure is detected, and how easily it is repaired. All of these factors can be weighted based on their effects.

Benefits

  • Used to determine potential failure modes, allowing for actions to decrease risk levels
  • Allows prioritizing of failure modes and planning to prevent failures

How to Use

  • Step 1.  Working with all key team members, brainstorm possible failure modes and initiate the FMEA worksheet.
  • Step 2.  Analyze the possible effects of the failure modes.
  • Step 3.  Determine the likelihood of the failure mode occurring.
  • Step 4.  Rank the severity of the effects.
  • Step 5.  Rank the likelihood of the failure mode occurring.
  • Step 6.  Multiply the likelihood ranking by the severity ranking to determine a risk level.
  • Step 7.  Order the risk levels highest to lowest and beginning working to reduce the risk levels.
  • Step 8.  Document the FMEA and date it.
  • Step 9.  When finished the FMEA should look like the figure below.

Relevant Definitions

Brainstorm: Process for generating creative ideas and solutions through intensive and free group discussion.

Failure mode: A manner in which a process can fail.

Risk priority number: The sum of the likelihood ranking multiplied by the severity ranking.

Example

The CG FUY company is tasked with loading baggage onto cargo aircraft in support of a relief mission to a small African country. Each passenger is allowed to carry a certain amount of baggage which cannot be larger than the bin size and cannot weigh more than 20 kilograms.

An FMEA is completed to determine critical factors. The group brainstorms the possible problems and then determines the worst possible effects from each of the problems. They write these on the FMEA work sheet.

They then classify the effects into 10 categories, listed from bad to worst. By looking at their processes, they determine how often the events could occur. By multiplying the probability ranking by the effect ranking, they determine a risk priority number. The highest of these is then highlighted in every pre-work brief.

*NOTE: If they had previous experience, they could also determine how often they detect a failure, rank that, and then multiply it by the probability ranking and by the effect ranking to generate a stronger FMEA.

FMEA_Figure1

 

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