What Is an FMEA (Failure Mode and Effects Analysis)? – Systematic Risk Analysis in Manufacturing

A Failure Mode and Effects Analysis (FMEA) is a structured, preventive method for systematically identifying potential failure modes and analyzing and prioritizing their causes and effects before those failures actually occur. It is based on the harmonized AIAG-VDA FMEA Handbook, which unifies the previously separate AIAG and VDA methodologies. An FMEA provides a structured risk assessment; it is not an inspection method and does not replace control plans or operational process monitoring.

How Is FMEA Positioned Within Quality Management?

FMEA is anchored within quality management as a preventive element of quality assurance. Within a quality management system based on ISO 9001, FMEA supports the risk-based thinking required by the standard as well as the systematic planning of processes and actions, without ISO 9001 prescribing FMEA as a specific method.

What Is the Underlying Logic of FMEA?

The methodological logic of FMEA is based on three assessment dimensions evaluated for each potential failure mode:

• Severity: the seriousness of a failure’s effect on the downstream process, the product, or the customer.
• Occurrence: the likelihood that the underlying failure cause will occur.
• Detection: the likelihood that an existing detection control will identify the failure or its cause before it has an effect.

These three dimensions allow different potential failure modes to be assessed on a comparable basis, without in themselves prescribing specific actions.

How Are Risks Rated in FMEA – RPN or Action Priority?

Traditionally, the three rating dimensions were combined into the Risk Priority Number (RPN), calculated as Severity × Occurrence × Detection. The harmonized AIAG-VDA FMEA Handbook (2019) replaced this practice with Action Priority (AP): instead of a calculated figure, AP assigns each potential failure mode to one of three categories – High, Medium, or Low – using a defined lookup table in which Severity is given priority weighting. The reasoning: under RPN, failure modes with very different practical implications – for example, a safety-relevant failure with low occurrence versus a frequent but non-critical failure – could produce the same numerical score and therefore end up with the same priority. AP is designed so that high Severity cannot be mathematically offset by favorable Occurrence or Detection ratings. Organizations that continue to track RPN values for internal trend analysis use them, per the AIAG-VDA Handbook, as a supplementary metric rather than the sole basis for decisions.

What Is the Methodological Structure of FMEA?

The AIAG-VDA FMEA Handbook describes a seven-step approach: planning and preparation, structure analysis, function analysis, failure analysis, risk analysis, optimization, and results documentation. These seven steps replace the previously separate approaches of AIAG (4th edition) and VDA Volume 4 and now form the shared methodological basis for FMEA practitioners in both systems.

What Types of FMEA Are Distinguished?

Depending on the object of analysis, different types of FMEA are applied:

• System FMEA: analysis of complex systems and the interactions between their components.
• Design FMEA: examination of potential failures in product or design engineering, prior to the start of series production.
• Process FMEA: analysis of risks within manufacturing or service processes.

The choice of FMEA type depends on the object being examined and its point in the product development lifecycle; the results of a Design FMEA typically feed into the subsequent Process FMEA as an input.

How Does FMEA Differ From a Control Plan and SPC?

FMEA is an analytical method for risk identification and does not itself provide operational process monitoring. A control plan translates the critical characteristics and risks identified in the FMEA into concrete, operational inspection and reaction requirements. Statistical Process Control (SPC) is used for the ongoing monitoring of defined process characteristics based on measured values over time. FMEA, control plan, and SPC therefore fulfill distinct, complementary roles that build on one another: FMEA identifies and prioritizes risks, the control plan defines the resulting operational inspection measures, and SPC monitors actual process performance.

What Role Does FMEA Play in Industrial Manufacturing?

In manufacturing, FMEA is used primarily for the preventive safeguarding of products and series processes, before failures occur in series production. In the automotive sector, evidence of a completed Design or Process FMEA is regularly part of the initial sample inspection within the PPAP process. An FMEA is typically revised when the design, the process, the production equipment used, or newly identified failure causes change; it is therefore a living document rather than a one-time analysis.

FAQ – Frequently Asked Questions About FMEA

What is the goal of an FMEA?

The goal of an FMEA is the early, structured identification of potential failures, along with a comparable assessment and prioritization of the associated risks before those failures occur.

Is FMEA a mandatory requirement?

No. FMEA is not mandated by normative requirements as such, but in the automotive sector it is regularly required as a recognized risk analysis method via IATF 16949 and customer-specific requirements.

What replaced the Risk Priority Number (RPN) with Action Priority (AP)?

Since the harmonized AIAG-VDA FMEA Handbook of 2019, the Risk Priority Number has been replaced by Action Priority, which assigns each potential failure mode to High, Medium, or Low using a defined lookup table that gives priority weighting to Severity.

Does an FMEA replace inspections or controls?

No. FMEA is a preventive analytical method and does not replace operational inspection or monitoring measures such as a control plan or Statistical Process Control.

What distinguishes System, Design, and Process FMEA?

System FMEA examines interactions within complex systems, Design FMEA examines potential failures in product or design engineering, and Process FMEA examines risks within manufacturing or service processes.

How many steps does FMEA comprise under the AIAG-VDA Handbook?

The harmonized AIAG-VDA FMEA Handbook describes a seven-step approach, from planning through structure, function, failure, and risk analysis to optimization and results documentation.

Is FMEA dependent on software?

The method is fundamentally independent of software; IT systems support documentation, rating logic, and evaluation, but do not replace the underlying technical analysis.

Standards and Regulations

The harmonized AIAG-VDA FMEA Handbook (1st edition, 2019) describes the seven-step methodology, the rating tables for Severity, Occurrence, and Detection, and the Action Priority logic for risk assessment, and is a central reference source for FMEA in the automotive sector. ISO 31000 provides general principles and guidelines for risk management, to which the risk-based logic of FMEA is methodologically related, without ISO 31000 prescribing FMEA as a specific procedure. ISO Guide 73 defines the underlying risk management terminology. Within a quality management system based on ISO 9001, FMEA supports the risk-based thinking required by the standard. In the automotive sector, IATF 16949 additionally requires the application of suitable methods for risk analysis.

Related Internal Content

• Control plan as the operational implementation of identified risks
• Statistical Process Control for ongoing process monitoring
• Action management for tracking derived measures