If failure is not visible until needed, which type is this?

• A. Functional Failure
• B. Potential Failure
• C. Hidden Failure
• D. Latent Failure

Answer: (C)

A fault that isn’t seen until the system is really relied upon is a latent failure. It sits in the system without affecting normal operation, only becoming evident when a specific demand or challenging condition arises. This makes it hard to detect during routine checks because the fault doesn’t manifest under everyday use, but the moment you push the system to perform at higher loads or under unusual scenarios, the fault reveals itself. A practical example is a sensor or actuator that works fine during normal flow but fails to respond correctly during peak conditions, or redundancy that masks a fault until the backup path is needed. To counter latent failures, maintenance and design rely on targeted tests that mimic demanding conditions, along with redundancy and diagnostics to catch faults before they impact performance.