Failure analysis questions.

83 failure analysis questions from the bank, ready to practice out loud.

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Root cause: five whys, fishbone & causal layers STAR and CARL: structuring your story Blameless postmortems & debriefs that change something Material selection: environment, lifecycle & failure modes Preserve the evidence, reconstruct the sequence Prevention that sticks: CAPA & the hierarchy of controls

All 83 questions

Bridge girder crack hypothesesA 30-year-old highway bridge developed unexpected cracks in a girder. Walk me through your initial hypotheses.Root cause hypothesisSenior–leadership

Evidence preservation at failure sitesWalk me through how you'd preserve and prioritize evidence at the site of a structural failure.Evidence gatheringSenior–leadership

Reconstructing unwitnessed failuresWalk me through how you'd reconstruct the sequence of a failure when no one was present at the time.Sequence reconstructionSenior–leadership

Primary cause versus contributing factorsWalk me through how you'd distinguish primary cause from contributing factors in a complex failure.Contributing factorsSenior–leadership

Structuring prevention recommendationsWalk me through how you'd structure prevention recommendations after identifying a failure cause.Prevention recommendationsSenior–leadership

Pressure vessel weld crack hypothesesA weld in a pressure vessel cracked under nominal operating conditions. Walk me through your hypotheses.Root cause hypothesisSenior–leadership

Evidence destroyed by respondersWalk me through how you'd handle a failure where the most informative evidence has been destroyed by responders.Evidence gatheringSenior–leadership

Conflicting witness accountsWalk me through how you'd handle conflicting witness accounts of a failure.Sequence reconstructionSenior–leadership

Failure with multiple liable partiesWalk me through how you'd handle a failure where multiple parties have potential liability.Contributing factorsSenior–leadership

Industry-wide implementation barriersWalk me through how you'd communicate prevention recommendations when implementation would require an industry-wide change.Prevention recommendationsSenior–leadership

Failures without known patternsWalk me through how you'd approach a failure that doesn't match any known pattern.Root cause hypothesisSenior–leadership

Evidence collection under pressureWalk me through how you'd handle evidence collection when there's pressure to restore operations quickly.Evidence gatheringSenior–leadership

Using simulation to reconstruct failuresWalk me through how you'd use simulation to reconstruct a failure event.Sequence reconstructionSenior–leadership

Identifying latent contributing factorsWalk me through how you'd identify latent factors that contributed to a failure but weren't direct causes.Contributing factorsSenior–leadership

Writing actionable broad recommendationsWalk me through how you'd write recommendations that are specific enough to act on but general enough to apply broadly.Prevention recommendationsSenior–leadership

Multiple equally likely causesWalk me through how you'd handle a failure where multiple causes look equally likely.Root cause hypothesisSenior–leadership

Access restrictions from manufacturersWalk me through how you'd respond when the manufacturer or operator wants to limit what you can examine.Evidence gatheringSenior–leadership

Logs and physical evidence mismatchWalk me through how you'd handle a failure where data logs and physical evidence don't match.Sequence reconstructionSenior–leadership

Organizational rather than technical failureWalk me through how you'd handle a failure that's primarily organizational rather than technical.Contributing factorsSenior–leadership

Avoiding problem transfer between systemsWalk me through how you'd avoid recommendations that just transfer the problem to another part of the system.Prevention recommendationsSenior–leadership

Cause ruled safe by standardsWalk me through how you'd handle a failure where the suspected cause has been ruled safe by the standards body.Root cause hypothesisSenior–leadership

Handling suspected counterfeit componentsWalk me through how you'd handle suspected counterfeit components found post-failure.Evidence gatheringSenior–leadership

Investigating when timeline is contestedWalk me through how you'd handle a failure where the timeline is contested.Sequence reconstructionSenior–leadership

Resisting pressure to narrow investigationWalk me through how you'd respond when stakeholders push to limit the investigation to a narrow set of causes.Contributing factorsSenior–leadership

Client refusing prevention recommendationsWalk me through how you'd handle prevention recommendations that the client doesn't want to implement.Prevention recommendationsSenior–leadership

Multi-disciplinary investigation teamWalk me through how you'd structure an investigation team for a complex multi-disciplinary failure.Root cause hypothesisSenior–leadership

Failure under changed standardsWalk me through how you'd handle a failure where the relevant standards have changed since the original design.Evidence gatheringSenior–leadership

Testing failure hypothesis with samplesWalk me through how you'd test a hypothesis about a failure using a physical sample.Sequence reconstructionSenior–leadership

Reporting contested primary causeWalk me through how you'd describe contributing factors in a report when the primary cause is contested.Contributing factorsSenior–leadership

Redesign versus refurbish versus replaceWalk me through how you'd think about whether a failure means redesigning, refurbishing, or replacing.Prevention recommendationsSenior–leadership

Gear failure before rated lifespanA gear in a conveyor system broke after six months of service, well before its rated lifespan. What are your initial hypotheses for why this might have happened?Root cause hypothesisEntry–mid

Collecting evidence from pipe ruptureYou arrive at a site where a pipe has ruptured and fluid has leaked everywhere. What physical evidence would you try to collect first, and why?Evidence gatheringEntry–mid

Determining when component failedAn electronic component failed, but the failure wasn't noticed until hours later. How would you determine when the failure actually occurred?Sequence reconstructionEntry–mid

Weighing undersizing versus ventilationA motor overheated and failed. You find it was undersized for the application and also poorly ventilated. How would you explain which factor was more important?Contributing factorsEntry–mid

Preventing contaminated lubricant failureAfter finding that a bearing failed due to contaminated lubricant, what recommendations would you make to prevent this in the future?Prevention recommendationsEntry–mid

Software valve unexpected closure causesA software-controlled valve closed unexpectedly, causing a process shutdown. What are three possible root causes you would investigate?Root cause hypothesisEntry–mid

Documenting failed component for labYou need to document a failed component that will be shipped to a lab for analysis. What information and photos should you capture before it leaves the site?Evidence gatheringEntry–mid

Tank overflow, sensor shows halfA tank overflow occurred, but the level sensor logs show the tank was only half full. How would you figure out what actually happened?Sequence reconstructionEntry–mid

Overtorqued bolt with pre-existing crackA bolt broke during installation. You find it was both overtorqued and had a pre-existing crack. How do you determine which was the primary cause?Contributing factorsEntry–mid

Operator error beyond procedure complianceYou've determined that a pump failed because the operator didn't follow the startup procedure. What recommendations would you make beyond just 'follow the procedure'?Prevention recommendationsEntry–mid

Battery pack swelling and failureA battery pack in a device swelled and stopped working. What hypotheses would you consider about what caused this?Root cause hypothesisEntry–mid

Corrosion role in component failureDuring a failure investigation, you notice corrosion on multiple components, not just the failed one. How would you decide what role corrosion played in the failure?Contributing factorsEntry–mid

Human error as insufficient conclusionA root-cause review just concluded 'human error' and everyone seems satisfied. Why is that answer suspect, and what would you ask next?Contributing factorsMid–leadership

ML model degradation investigationYour team's ML model degraded quietly for three months before anyone noticed, and the post-incident review is yours to run. Where do you start, and what makes this different from reviewing an outage?Root cause hypothesisSenior–leadership

System working as designed, harmAn automated decision system produced a harmful outcome while operating exactly as designed — nothing technically broke. How do you investigate a failure with no defect in it?Contributing factorsSenior–leadership

Investigation with missing telemetryMidway through an incident review you realize the telemetry needed to answer the central question was never built. What do you do with the investigation — and what do you do about the gap?Evidence gatheringMid–leadership

Same failure recurred after fixYour team shipped a fix after what felt like a thorough root-cause review, and the same failure recurred a month later. What now?Prevention recommendationsMid–leadership

Skipped runbook step, blameless reviewYour organization runs blameless postmortems, but this time an engineer skipped an explicit runbook step. How do you keep the review honest about that without turning it into a trial?Postmortem facilitationSenior–leadership

Investigating near misses differentlyTell me about a near miss — a failure that almost happened on your watch but didn't. How did you treat it differently from one that did, and should you have?Near Miss analysisMid–leadership

Vendor failure with incomplete evidenceA critical vendor's failure took your operation down, and the vendor's own postmortem is two thin paragraphs. How do you run your side of the investigation when half the evidence belongs to someone else?Evidence gatheringSenior–leadership

Bad training data, passed validationA model failure traces back to bad training data that passed every validation check you had. How would you reconstruct how it got in — and decide where the real defect lives?Sequence reconstructionSenior–leadership

When to stop asking whyIn a root-cause review, how do you decide when to stop asking 'why'? Give me a real example of where you drew the line and what you left unexamined.Root cause hypothesisMid–leadership

Auditing postmortem follow-throughSix months after a serious incident, how would you audit whether the postmortem actually changed anything?Prevention recommendationsSenior–leadership

Investigating failures your metrics denyCustomers are reporting real harm, but every dashboard for that period stayed green. How would you investigate a failure your own metrics insist never happened?Evidence gatheringSenior–leadership

Connecting repeated factors across incidentsYou've read your organization's last ten incident reports and the same contributing factor keeps appearing under different names. How do you make the case that this is one systemic failure, not ten one-offs?Contributing factorsSenior–leadership

Reviewing blame-focused postmortem draftsA junior engineer's postmortem draft names individuals and assigns blame throughout. As the reviewer, what do you change in the document — and what do you teach them?Postmortem facilitationSenior–leadership

Data center cooling system failureA data center cooling system failed, causing server overheating in three racks before automatic shutdown. Walk me through your initial hypotheses about root cause.Root cause hypothesisMid–senior

Prioritizing evidence with overwriting logsWalk me through how you'd prioritize evidence collection when a failure involves both physical components and digital logs that are overwriting in real-time.Evidence gatheringSenior–staff+

Reconstructing pharmaceutical batch failureA pharmaceutical batch failed sterility testing three days after production. Walk me through how you'd reconstruct what happened during those 72 hours.Sequence reconstructionMid–senior

Design flaws versus maintenance issuesWalk me through how you'd separate design flaws from maintenance issues when both appear to contribute to a mechanical failure.Contributing factorsMid–senior

Framing prevention after operator errorAfter identifying operator error as the proximate cause, walk me through how you'd frame prevention recommendations to avoid a blame-focused response.Prevention recommendationsSenior–leadership

Facilitating postmortem with defensive teamWalk me through how you'd facilitate a postmortem when the team is defensive because this is their third failure in six months.Postmortem facilitationSenior–leadership

Analyzing surgical robot near-missA surgical robot experienced a momentary loss of position tracking that corrected itself before any patient harm. Walk me through your near-miss analysis approach.Near Miss analysisSenior–staff+

Black-box third-party module failureWalk me through how you'd build a failure hypothesis when the component that failed was a black-box third-party module with no internal documentation available.Root cause hypothesisMid–staff+

Turbine blade debris on farmlandA wind turbine blade separated during operation. Walk me through how you'd secure the failure site when debris is scattered across private farmland.Evidence gatheringMid–senior

Latent defect versus environmental changeWalk me through how you'd distinguish between a latent design defect and recent environmental changes when analyzing a failure in a system that's operated successfully for five years.Contributing factorsSenior–staff+

Prevention when failure was predictableWalk me through how you'd structure prevention recommendations when your analysis reveals the failure was predictable from ignored warning signs.Prevention recommendationsSenior–leadership

Running postmortem with executives presentWalk me through how you'd run a postmortem when the failure caused significant customer impact and executives are attending the session.Postmortem facilitationStaff+–leadership

Investigating pipeline sensor near-missAn oil pipeline pressure sensor briefly exceeded its alarm threshold but returned to normal within 30 seconds. Walk me through your near-miss investigation approach.Near Miss analysisMid–senior

Evidence gathering in clean roomWalk me through how you'd gather evidence when a failure occurred in a clean room environment and your investigation could contaminate ongoing production.Evidence gatheringMid–senior

Contradictory sensor telemetryWalk me through how you'd reconstruct the failure sequence when the only available evidence is contradictory telemetry from redundant sensors.Sequence reconstructionSenior–staff+

Assessing training gaps without recordsWalk me through how you'd assess whether inadequate training was a contributing factor without access to training records or the ability to interview the operator.Contributing factorsMid–senior

Preventing rare failure combinationsWalk me through how you'd develop prevention recommendations when the root cause is a rare combination of conditions unlikely to recur naturally.Prevention recommendationsSenior–staff+

Resolving cross-functional blameWalk me through how you'd facilitate a cross-functional postmortem when hardware, software, and operations teams are each blaming the other groups.Postmortem facilitationSenior–leadership

Analyzing unnecessary safety activationsA construction crane's load limiter activated unnecessarily, stopping work but preventing no actual danger. Walk me through your near-miss analysis approach.Near Miss analysisEntry–mid

Hypothesizing from destroyed componentsWalk me through how you'd develop failure hypotheses when the failed component is so damaged that forensic testing cannot determine its pre-failure state.Root cause hypothesisSenior–staff+

Reconstructing timeline with clock driftWalk me through how you'd reconstruct the timeline of a chemical reactor upset when the control system's clock was found to be 14 minutes fast.Sequence reconstructionMid–senior

Evaluating cost-cutting as a factorWalk me through how you'd evaluate whether organizational cost-cutting was a contributing factor when you have limited visibility into budget decisions.Contributing factorsSenior–leadership

Distinguishing real from lab artifactsA finished tablet lot returns an out-of-specification assay result on one of six samples. Walk me through your initial hypotheses before you decide whether it's real or a lab artifact.Root cause hypothesisMid–senior

Separating root cause from contributorsA blend uniformity failure shows up intermittently across several batches of the same product. Walk me through how you'd separate the true root cause from the contributing factors.Contributing factorsSenior–leadership

Securing evidence from contaminationA settle plate in your Grade A filling zone grows an organism above the action limit. Walk me through what evidence you'd secure, and in what order, before it's disturbed.Evidence gatheringMid–senior

Explaining late-stage stability failuresA commercial product fails a stability time point at 18 months when earlier points passed. Walk me through how you'd reconstruct what changed to explain the drop.Sequence reconstructionSenior–leadership

Systemizing prevention across equipmentYou've traced a cross-contamination event to a shared piece of equipment and an incomplete cleaning verification. Walk me through how you'd structure prevention so it addresses the system, not just that one line.Prevention recommendationsSenior–leadership