What Are Failure Modes? Types, Examples, and How to Identify Them

Every product can fail, and the way it fails matters as much as whether it fails. When teams map out those failure paths early, they can write better requirements, build in the right safeguards, and catch problems before they reach a customer or a patient. Failure mode analysis turns “what could go wrong?” into a structured record that connects to every engineering decision that follows.

This guide covers what failure modes are, the major types across mechanical, electrical, software, and human systems, real-world examples, and how teams identify and prioritize them through Failure Mode and Effects Analysis (FMEA).

What Are Failure Modes?

A failure mode is the specific way something fails. It describes what you’d observe when you look at the failed part at whatever level of the system you’re analyzing.

One detail that trips teams up: the same physical event can be a cause, a mode, or an effect depending on which level of the system you’re looking at. A valve that fails to open is a failure mode at the valve level, a failure effect at the hydraulic subsystem level, and a failure cause at the mission level. Every FMEA worksheet row needs to state what item you’re analyzing and at what system level, or the ratings become unreliable.

Failure Mode vs. Failure Cause

A failure cause is the underlying reason something fails, whether that’s a material problem, a design flaw, or a manufacturing defect. It comes before the failure mode in the chain of events. For example, corrosion on a conductor is the cause. The open circuit it creates is the failure mode.

Failure Mode vs. Failure Effect

A failure effect is what happens to the system as a result of the failure mode. Effects can be local, felt at the next level up, or system-wide. In the conductor example, the open circuit is the failure mode and the loss of signal is the failure effect at the next level up. Mixing up these three terms in your FMEA documentation leads to audit findings and incorrect risk ratings.

Types of Failure Modes

A system that combines mechanical, electrical, and software subsystems can experience failures in any domain. The most dangerous failures often cross domain boundaries, which is why teams need to understand the major categories.

Mechanical Failure Modes

Mechanical failure modes include fatigue, stress corrosion, creep, and wear. Fatigue failures give no warning. Tiny cracks form under repeated stress, grow over time, and then the part breaks without advance notice. Creep is when a material slowly deforms under constant load at high temperature. Wear includes abrasive, adhesive, erosive, and fretting types.

Electrical Failure Modes

Electrical failure modes include electromigration, time-dependent dielectric breakdown (TDDB), stress migration, and hot carrier injection. At the circuit board level, the most common failures are open circuits from cracked solder joints and short circuits from solder bridges or stray conductive debris.

Software and Firmware Failure Modes

Software doesn’t wear out, but it fails in ways that are just as serious. Logic errors can produce wrong outputs without crashing, which makes them harder to spot than obvious failures. Race conditions cause failures that don’t happen the same way twice, making them notoriously hard to reproduce. And if firmware handles states incorrectly, it can leave hardware stuck in an unsafe condition.

Human and Process Failure Modes

Human failure modes usually start with an operator or assembly mistake. Operator errors get logged in Corrective and Preventive Action (CAPA) workflows, categorized by type, and traced back to the process step where they happened. Assembly errors during manufacturing, like placing the wrong part or applying the wrong torque, fall under process FMEA.

Failure Mode Examples in Regulated Industries

These recalls and accident investigations show how failure modes surface in products already on the market. Each example traces the chain from the failure mode to the consequence that triggered regulatory action.

Medical Device Failure Mode Examples

Consider an insulin pump paired with a companion mobile app. A software bug in the app drains the pump’s battery faster than expected. The pump shuts down and stops delivering insulin. Even though the failure starts in the app, the patient consequence is interrupted therapy. When software can interrupt treatment delivery, it belongs in the risk management process alongside the device hardware.

Automotive Failure Mode Examples

Imagine an ignition switch that doesn’t hold its position firmly enough. A heavy keychain or a bumped knee can rotate it out of “run” during normal driving. In one motion, that rotation cuts power to both the airbag system and the power steering.

The airbags can’t deploy on impact and the driver loses steering assist at the worst possible moment. This kind of failure crosses system boundaries, which is why system-level FMEA needs to look at how subsystems interact, not just how they work in isolation.

Aerospace and Defense Failure Mode Examples

Consider a flight control system that relies on a single Angle of Attack (AOA) sensor with no way to verify the reading against a second sensor. When that sensor feeds bad data, the system repeatedly pushes the nose down and the flight crew struggles to override it. The fix is straightforward in concept: the software should compare readings from both AOA sensors and shut off the augmentation when they disagree by more than a set threshold, like 5.5 degrees.

How to Identify Failure Modes in Complex Systems

The AIAG-VDA FMEA Handbook replaced older FMEA manuals with a seven-step process. The key change: you have to define the system structure and map out functions before you identify any failure modes.

1. Map System Functions Before Analyzing Failures

A failure mode is a way a function fails, so you need to define your functions first. Structure analysis breaks the system down into a hierarchy of parts. Function analysis defines what each part must do, its performance requirements, and how it connects to other parts. The AIAG-VDA approach uses boundary diagrams and Parameter Diagrams (P-Diagrams) to map out inputs, outputs, and variation before failure analysis begins.

2. Use Cross-Functional Teams to Surface Hidden Failure Modes

FMEA is a team activity, not a solo exercise. SAE J1739 defines it as an analysis done by a cross-functional team of experts. Some failure modes aren’t visible to any single discipline, which is why you need multiple perspectives in the room.

A reliability engineer might catch a heat-related degradation that a software architect would never think of. A manufacturing engineer might spot a tolerance buildup that neither of them would expect.

3. Score Each Failure Mode by Severity, Occurrence, and Detectability

Once failure modes are identified, teams rate each one across three dimensions:

• Severity: How bad is the consequence for the end user or the system? A failure that could injure a patient or cause loss of vehicle control scores a 9 or 10 no matter how unlikely it seems.
• Occurrence: How likely is it that the cause actually produces this failure during the product’s lifetime? Ratings come from field data or engineering judgment about how well the cause has been controlled.
• Detection: How likely are your current controls to catch the failure before it reaches the customer? Detection ratings get worse when there’s no verification activity linked to the failure mode.

These three ratings interact in ways that are easy to misread. The classic Risk Priority Number (RPN) multiplies all three on a 1-to-10 scale into a single score. The problem: that single number can hide high-severity failures when the occurrence and detection scores happen to be low. The AIAG-VDA handbook’s Action Priority method fixes this by evaluating severity first. A failure mode with catastrophic consequences always requires action, no matter what its other ratings say.

How Failure Modes Connect to FMEA

FMEA is the structured method for documenting failure modes, their causes and effects, current controls, and recommended actions. Every failure mode identified in the analysis becomes a row in the FMEA worksheet and connects back to the requirements and risk controls that govern it.

Design FMEA vs. Process FMEA

Design FMEA (DFMEA) asks: will this design meet its engineering specs? It works from the top down, starting at the system level and drilling into subsystems and components. Process FMEA (PFMEA) asks: will our manufacturing and assembly process build the product correctly? It’s organized around process steps and the specific work done at each step.

Using RPN to Prioritize Failure Modes for Action

The RPN method’s biggest weakness is that two failure modes can get the same score while posing very different levels of risk. A catastrophic failure (severity 10) with low occurrence and good detection can score the same as a minor failure (severity 3) with mid-range ratings across the board. That’s the problem Action Priority solves. Any failure mode with a severity of 9 or 10 requires a corrective response no matter where its RPN falls.

Linking Failure Modes to Corrective and Preventive Actions

Step 6 of the AIAG-VDA method is where FMEA findings turn into engineering action. Each response plan targets a specific part of the risk:

• Design changes: Adding a backup (redundancy) reduces the impact if the failure happens.
• Process changes: Tighter tolerances make it less likely the failure cause occurs.
• Verification activities: Better testing catches the failure before it reaches the customer.

FDA quality-system guidance requires that corrective and preventive actions are implemented and verified with documentation. The link from FMEA to CAPA is a direct audit trail.

How Jama Connect Strengthens Failure Mode Analysis

Failure mode analysis is only as reliable as the requirements it’s built on. A requirement like “the device shall respond quickly” with no defined threshold means every team interprets it differently. You can’t accurately rate severity or occurrence until you’ve nailed down the actual criterion. Spreadsheet-based FMEA makes this worse because there’s no version control, no change notifications, and no permanent audit trail.

Jama Connect® is a requirements management platform that manages FMEA records alongside requirements in a single connected system. Because it supports bidirectional traceability, a change to any requirement automatically flags every linked FMEA record, risk assessment, and test case for review.

Connecting Failure Mode Analysis to Your Engineering Workflow

The failure modes that cause the most damage in regulated industries aren’t exotic or unpredictable. They’re the ones that fall between teams, between disciplines, or between documents that were never connected. A requirement changes and nobody updates the FMEA. A safety function relies on a single sensor because the hazard analysis never questioned the architecture.

Closing these gaps means connecting failure mode analysis to the requirements and tests it depends on. When those connections are live, a change to any upstream item flags everything downstream for review before the gap reaches an auditor. Start a 30-day free trial of Jama Connect to see how it fits your team’s workflow.

Frequently Asked Questions About Failure Modes

What is the difference between a failure mode and a failure cause?

Swapping cause and mode in the FMEA worksheet is the most common mistake. A cracked solder joint is the failure mode because that’s what you observe when you inspect the board. Electromigration is the cause, and each one needs its own corrective action. When they’re mixed up, the occurrence rating ends up on the wrong row and the risk score becomes unreliable.

What is an example of a failure mode in aerospace?

Relying on a single sensor is one of the most dangerous failure modes in safety-critical flight control systems. When the system trusts one sensor with no cross-check, a single bad reading can produce a control command the crew can’t override. The fix is dual-sensor cross-checking that automatically disables the function when the two readings disagree beyond a set threshold. That fix becomes a new design requirement and a new test case linked to traceability records.

How does FMEA use failure modes?

Each identified failure mode becomes a row in the FMEA worksheet. The team links that row to its cause, records the effects at the local, next-higher, and system levels, documents what controls are in place, and assigns risk ratings. These entries are only reliable when you clearly state what item you’re analyzing and at what level of the system. Tools like Jama Connect help teams maintain the links between FMEA records and the requirements they trace back to.

What tools are used for failure mode identification?

Structure analysis, function analysis, boundary diagrams, and P-Diagrams all help teams identify failure modes before FMEA scoring begins. The AIAG-VDA 7-step approach puts these steps first because you can’t figure out how a function fails if you haven’t defined what it’s supposed to do. Fault Tree Analysis (FTA) gives you a complementary top-down view, and Hazard and Operability Studies (HAZOP) cover process-level review.