Root Cause Analysis — 5-Why and Fishbone

Overview

An original, practical introduction to root cause analysis for aviation safety and quality work, with hands-on emphasis on the 5-Why technique and the fishbone (Ishikawa) diagram — from defining the problem to verifying that corrective action actually prevents recurrence.

Course content is maintained against the latest applicable regulatory amendments reviewed as of 21 June 2026.

Syllabus

14 modules, completed in order — each with its keywords and objective.

1. 1

   Welcome and course scope

   scopeaudienceassessment

   Objective: Orient to the root cause analysis course scope and assessment.

2. 2

   What a root cause really means

   root causesymptomcontributing factordefinitions

   Objective: Define what a root cause really is versus symptoms and contributing factors.

3. 3

   The RCA process end to end

   RCA processstepsproblem to verification

   Objective: Describe the end-to-end RCA process.

4. 4

   Defining the problem and gathering evidence

   problem statementevidencescopedata

   Objective: Define the problem precisely and gather the right evidence.

5. 5

   Cause-and-effect thinking and just culture

   cause and effectjust cultureblame-freesystems thinking

   Objective: Apply cause-and-effect thinking within a just culture.

6. 6

   Fishbone (Ishikawa): what it is and when to use it

   fishboneIshikawacategories6Ms

   Objective: Explain what a fishbone diagram is and when to use it.

7. 7

   Building a Fishbone step by step

   fishbone constructionbrainstormingcategoriesbranches

   Objective: Build a fishbone diagram step by step.

8. 8

   The 5-Why technique: the discipline

   5-Whyiterative questioningdisciplineevidence

   Objective: Apply the 5-Why technique with discipline.

9. 9

   5-Why in practice: worked examples and pitfalls

   5-Why examplespitfallssingle-trackjumping to causes

   Objective: Recognise common 5-Why pitfalls through worked examples.

10. 10

    Combining the tools

    combining toolsfishbone + 5-Whyworkflow

    Objective: Combine the fishbone and 5-Why tools effectively.

11. 11

    A brief tour of other RCA tools

    fault treebarrier analysischange analysistools

    Objective: Recognise other RCA tools and when they help.

12. 12

    From cause to corrective action

    corrective actionroot cause to fixSMART actions

    Objective: Translate root causes into effective corrective actions.

13. 13

    Verifying effectiveness and sharing learning

    verificationeffectivenesslessons learnedsharing

    Objective: Verify corrective-action effectiveness and share the learning.

14. 14

    Summary, pitfalls checklist, and applying RCA

    summarypitfalls checklistapplication

    Objective: Consolidate RCA practice with a pitfalls checklist.

Final assessment

• Format: 12 multiple-choice questions drawn from the course question bank, with the options shuffled each attempt.
• Pass mark: 75%.
• Certificate: issued automatically on passing, according to Methodology aligned with ICAO Doc 9859 (SMS) occurrence investigation and quality-system corrective action.