CMRP Root Cause Analysis and Failure Investigation 2

Question 1

What does FMEA stand for, and what is its primary output?

Accepted Answer

Failure Modes and Effects Analysis; a prioritized list of failure risks with recommended actions

Answer

FMEA identifies each potential failure mode, its effects on the system, and its causes, then prioritizes them by Risk Priority Number (RPN) to guide preventive action.

Question 2

In FMEA, what does the Risk Priority Number (RPN) represent?

Accepted Answer

The product of severity, occurrence, and detection scores used to rank failure mode risk

Answer

RPN = Severity × Occurrence × Detection, where each factor is rated on a scale (typically 1–10), giving a composite risk score to prioritize corrective actions.

Question 3

What is a 'failure mode' in the context of reliability engineering?

Accepted Answer

The specific way in which a component or system fails to perform its required function

Answer

A failure mode describes the observable manner in which a failure occurs (e.g., fracture, wear, corrosion, leakage), distinct from the cause or effect of that failure.

Question 4

Which type of failure pattern shows a high initial failure rate, low mid-life rate, and increasing rate at end of life—commonly called the 'bathtub curve'?

Accepted Answer

Pattern A (bathtub)

Answer

Pattern A (the bathtub curve) has three zones: infant mortality (early failures from defects), random failures (stable mid-life), and wear-out (age-related degradation).

Question 5

In a root cause analysis investigation, why is it critical to preserve the failure scene before disassembly?

Accepted Answer

Physical evidence of failure origin, direction of propagation, and contributing conditions may be destroyed during disassembly

Answer

Premature disassembly can destroy fracture surfaces, wear patterns, and positional evidence that are essential to correctly identifying the failure mechanism and root cause.

CMRP - Certified Maintenance and Reliability Professional Practice Test

CMRP - Certified Maintenance and Reliability Professional Practice Test

CMRP Root Cause Analysis and Failure Investigation 2