Step 9 · Root-cause method
Root-cause analysis
Expert mode offers any of the RCA methods. Remember the separation the pack requires: the mechanism is what physically happened; the root cause is the correctable reason those conditions existed or were not controlled.
Cause-and-effect (Fishbone / Ishikawa)
5 Whys
Change / Difference Analysis
Events & Causal Factors (timeline)
Barrier Analysis
FMEA / FMECA
Fault Tree Analysis
5 Whys
Iteratively ask why until a deeper, correctable cause is reached. Attach evidence at each step; stop at a system/design/process/control cause, not at a mechanism or at 'human error'. The 'five' is a heuristic, not a target.