FMEA is your bottom-up evidence: the systematic walk through how components and functions fail and what those failures do. Its value multiplies when it connects to the top-down fault tree analysis above it, which is exactly where most toolchains break the link. Safety Lab Aero keeps them connected.
Functional FMEA
Each row links to an aircraft sub-function and records the function failure mode (loss, erroneous, inadvertent, degraded) and its effects. Optionally link the row to the FHA failure condition it contributes to, closing the loop from functional FMEA back to the hazard assessment.
Piece-part (hardware) FMEA
- Each row links to a fault-tree basic event and records a component failure mode with its failure-mode fraction and rate.
- A component basic event takes the sum of its failure-mode rates, so multiple modes aggregate correctly rather than overwriting one another.
- Optionally choose a parent library component; the mode rate is computed from the component rate and the failure-mode fraction, and the published mode menu pre-fills the fractions.
- A coverage check warns when the failure-mode fractions for a basic event do not sum to one: i.e. part of the component failure rate is unmodeled.
One source of truth for failure data
The component library catalogs failure rates from public-domain sources (MIL-HDBK-217F, MIL-HDBK-338B, NPRD/EPRD-style data, NUREG-CR-6928 and others), with environment, quality and temperature factors. When several basic events reference the same library entry, Safety Lab Aero flags the shared dependency so you can decide whether it needs common-cause treatment, see CMA, PRA and ZSA.
Frequently asked questions
What is FMEA?
Failure Mode and Effects Analysis (FMEA) is a bottom-up method: for each function or component, list the ways it can fail (the failure modes), then work out the local effect, the effect on the next level up, and the end effect on the aircraft, along with how the failure is detected and any compensating provisions. In the ARP 4761A process the FMEA provides the failure rates and the evidence that feed the system safety assessment; the FMES groups modes with the same end effect so the fault tree can use them.
How does FMEA differ from fault tree analysis?
They work in opposite directions. FMEA starts at the bottom, from individual failure modes, and asks what each one causes. Fault tree analysis starts at the top, from an undesired event, and asks what combinations of failures could cause it. FMEA is exhaustive about single failures but cannot by itself express combinations; the fault tree handles combinations and quantifies them. In practice the two are connected: piece-part FMEA modes supply the rates for the fault tree's basic events.
Does the FMEA connect to the fault tree?
Yes. Piece-part FMEA rows link to fault-tree basic events and supply their rates, and functional FMEA rows can link to the FHA failure condition they contribute to. The FMEA is part of the same model, not a separate file.
How does it handle a component with several failure modes?
The basic event takes the sum of its failure-mode rates, and a coverage check warns if the failure-mode fractions do not sum to one, so unmodeled portions of the component rate are visible rather than hidden.
See it on your own analysis
Safety Lab Aero keeps functions, hazards, fault trees, FMEA, common-cause, requirements and verification in one connected model, from FHA to a certification-ready evidence package.