Root Cause Analysis(RCA)

An iterative root cause analysis technique that repeatedly asks 'Why?' (typically five times, though the actual number varies) to peel away successive layers of symptoms and intermediate causes until the fundamental root cause is identified. Each answer forms the basis of the next question. The method is effective for straightforward cause-and-effect chains but may need supplementing with other techniques for complex multi-causal events.

A cause-and-effect analysis tool (also called Ishikawa diagram or cause-and-effect diagram) that visually organizes potential causes of a problem into major categories branching from a central spine. Standard categories for manufacturing/maintenance include: Man (People), Machine (Equipment), Method (Procedure), Material, Measurement, and Mother Nature (Environment). Each category is explored for contributing causes.

A closed-loop process for systematically reporting failures, analyzing their root causes, implementing corrective actions, and verifying that those actions effectively prevent recurrence. FRACAS captures failure data, triggers investigation based on severity, tracks corrective action implementation, and feeds lessons learned back into the design, maintenance, and operating procedures.

An action taken to eliminate the root cause of a detected nonconformity, failure, or undesirable situation to prevent its recurrence. Corrective actions address why something went wrong, not just the immediate symptoms. They are distinguished from immediate actions (containment) and preventive actions (proactive measures for potential future problems).

The underlying reason or mechanism that initiates the process leading to a failure mode. A failure cause is the root-level factor — design deficiency, material defect, manufacturing flaw, operational condition, degradation mechanism, or human error — that creates the conditions for the failure mode to manifest. Each failure mode may have multiple independent causes.