FMEA / FMECA
Definition
Failure Mode and Effects Analysis is a bottom-up, inductive method listing what can fail in each component and the effect on the system. FMECA adds a criticality ranking combining probability and severity.
- FMEA
- Failure Mode and Effects Analysis, bottom-up inductive method
- FMECA adds
- Criticality ranking combining probability and severity
- Direction
- Bottom-up: from component failure to system effect
- Output
- Ranked list of failure modes and their consequences
Common questions
How does FMEA differ from a top-down root-cause method like fault tree analysis?+
FMEA works bottom-up, starting from each component and asking what could fail and what effect that has on the system, whereas fault tree analysis starts top-down from a defined system failure and works backward to find contributing causes. They are complementary rather than interchangeable.
Why add a criticality score in FMECA rather than just listing failure modes as in FMEA?+
A plain list of failure modes does not indicate which ones deserve attention first. FMECA ranks each mode by combining how likely it is with how severe its consequence would be, letting an investigator or engineer prioritise mitigation effort on the highest-risk failure paths.
When is FMEA typically applied in a forensic or incident-investigation context rather than during design?+
It can be used proactively during system design to anticipate failures, or retrospectively after an incident to systematically catalogue what components could have failed and whether the failure that actually occurred was foreseeable, which matters for questions of negligence or design adequacy.
Related terms
- 5-Whys
- An iterative questioning technique that moves from a symptom to underlying causes by asking 'why?' repeatedly until a systemic explanation is reached.
- Barrier Analysis
- A method that identifies the physical, administrative, and procedural barriers that should have prevented harm, and asks which barriers were absent, inadequate,...
- Fault Tree Analysis (FTA)
- A top-down, deductive Boolean logic model that works backward from a specific undesired top event through AND/OR gates to identify minimal cut...
- Minimal Cut Set
- In a fault tree, the smallest set of simultaneously failing basic events that is sufficient to cause the top event. Identifies the...
- Root Cause
- The fundamental, underlying deficiency from which the failure originated. Distinguished from immediate cause (the final physical event) and contributing factors. Root-cause analysis...