Part-66 Module 9 syllabus: what Appendix I requires, topic by topic

What does the Part-66 Module 9 syllabus contain?

Module 9, Human Factors, runs to ten sub-modules — 9.1 General through 9.10 The ‘Dirty Dozen’ and risk mitigation — since Regulation (EU) 2023/989 replaced Appendix I to Part-66 with effect from 12 June 2024. Every licence category is examined to the same depth from one level column, and the examination is 28 multiple-choice questions in 35 minutes with no essay. This guide walks the syllabus topic by topic, then the exam rules. How Module 9 relates to the Part-145 safety-training duty is set out in our hub on the training duties under Part-145.

The module exists to be examined: 66.A.25(a) requires every applicant for an aircraft maintenance licence to demonstrate knowledge of the applicable modules by examination, and the Appendix I modularisation matrix marks Module 9 with an X in every category column, A1 to A4, B1.1 to B1.4, B3, B2, B2L and C. Nobody with a Part-66 ambition routes around human factors. The same Appendix carries Module 10, Aviation Legislation — see our Module 10 syllabus guide for that module’s ten sub-modules topic by topic.

Module 9 at a glance

Figure	What it is
10 sub-modules	Module 9’s syllabus size — Appendix I to Part-66, as replaced by Regulation (EU) 2023/989
7 of 10 at level 2	Sub-modules examined at the deeper level; the remaining 3 (9.3, 9.5, 9.6) sit at level 1 — Appendix I to Part-66
28 questions, 35 minutes	Multiple-choice exam format for every licence category, no essay — Appendix II to Part-66, point 2.9
75% pass mark	Seven wrong answers out of 28 is the most a pass can absorb — Appendix II to Part-66
90 days	Standard wait to retake a failed module exam; 30 days after Part-147 retraining tailored to the failed subjects — Appendix II to Part-66, point 1.11
12 June 2024	Date the ten-sub-module Module 9 and its multiple-choice-only exam became applicable

What changed with Regulation (EU) 2023/989?

Three things, all live since 12 June 2024 in EASA member states. The module was renumbered from 9A to 9 and grew from nine sub-modules to ten. The old closing topic, hazards in the workplace, gave way to two new headings — 9.9 Safety management and 9.10 The ‘Dirty Dozen’ and risk mitigation — pulling the module towards the same safety-management ground that Part-145 safety training covers. And the essay question disappeared: the examination is multiple-choice only, as it now is for Module 10 too. For anyone choosing a course today the practical check is simple: the syllabus on offer should run to 9.10 and name Regulation (EU) 2023/989, because material written for the nine-topic Module 9A stops short of two examinable headings.

The ten sub-modules and their knowledge levels

Appendix I presents Module 9 as a table with one level column for all categories:

MODULE 9. HUMAN FACTORS — LEVEL: ALL 9.1 General — 2 9.2 Human performance and limitations — 2 9.3 Social psychology — 1 9.4 Factors that affect performance — 2 9.5 Physical environment — 1 9.6 Tasks — 1 9.7 Communication — 2 9.8 Human error — 2 9.9 Safety management — 2 9.10 The ‘Dirty Dozen’ and risk mitigation — 2

— Appendix I to Part-66, Module 9, as replaced by Regulation (EU) 2023/989

Seven topics at level 2, three at level 1 — and because the column reads ALL, a category A mechanic and a B2 avionics engineer sit the same exam at the same depth. AMC1 Appendix I to Part-66, Section 2, expands each heading into the sub-topics a course must reach.

What does each sub-module cover?

9.1 General (level 2). Why human factors matters at all: the incident record attributable to human error, and the need to take human performance into account in maintenance. The pre-2024 text opened the same way — this is where ‘Murphy’s law’ traditionally enters the syllabus.

9.2 Human performance and limitations (level 2). The individual as a system component: vision, hearing, information processing, attention and perception, memory, and the physical-access and claustrophobia limits that matter in a fuel tank or an avionics bay. These are the headings the pre-2024 Appendix I spelled out under the same title.

9.3 Social psychology (level 1). The group around the individual: responsibility shared between individual and team, motivation and de-motivation, peer pressure, culture, team working, and the effect of management and supervision. Level 1 keeps it to recognition rather than analysis.

9.4 Factors that affect performance (level 2). The classic degraders: fitness and health, stress, time pressure and deadlines, workload in both directions, sleep, fatigue and shift work, and alcohol, medication and drug effects. Examined at level 2 because these are the factors a certifying engineer manages daily.

9.5 Physical environment (level 1). Noise, fumes, illumination, climate and temperature, motion and vibration, and the working environment as an error condition.

9.6 Tasks (level 1). How the work itself shapes error: physical work, repetitive tasks, visual inspection and complex systems.

9.7 Communication (level 2). Within and between teams, work logging and recording, keeping current, and dissemination of information — the shift-handover territory where maintenance accidents keep being written.

9.8 Human error (level 2). Error models and theories, the error types seen in maintenance tasks, their implications, and avoiding and managing them.

9.9 Safety management (level 2). New with 2023/989, and AMC1 Appendix I Section 2 lists what it holds:

“9.9 Safety management: Risk management; Occurrence reporting; Safety culture; Just culture; Identifying, avoiding, and reporting hazards; Organisational human-factors programme: professionalism and integrity, error-provoking behaviour, reporting errors, disciplinary policy, error investigation, […]; Dealing with emergencies.” — AMC1 Appendix I to Part-66, Section 2

The old hazards-in-the-workplace material survives inside it — identifying, avoiding and reporting hazards, and dealing with emergencies — now framed by risk management, occurrence reporting and just culture.

9.10 The ‘Dirty Dozen’ and risk mitigation (level 2). The twelve preconditions the industry has taught since the Transport Canada programme of the 1990s — lack of communication, complacency, lack of knowledge, distraction, lack of teamwork, fatigue, lack of resources, pressure, lack of assertiveness, stress, lack of awareness and norms — followed by the mitigation methods for each. 2023/989 promoted what was long a training convention into examinable regulation.

How is Module 9 examined?

Appendix II fixes the format; a training provider cannot vary it:

“2.9. MODULE 9 – HUMAN FACTORS. Category A, B1, B3, B2 and B2L: 28 multiple-choice, no essay questions. Time allowed: 35 minutes.” — Appendix II to Part-66, point 2.9

That is 75 seconds per question, with the pass mark at 75% — at 28 questions, seven wrong answers is the most a pass can absorb. The 35-minute paper also sits far below the 90-minute threshold at which Appendix II point 1.12 allows an examination to be split into partial exams, so Module 9 is always sat in one sitting. Failing has a waiting cost:

“An examination in a module may not be retaken earlier than 90 days following the date of a failed examination in that module, except in the case of a maintenance training organisation approved in accordance with Annex IV (Part-147) which delivers a course of retraining tailored to the failed subjects in the particular module; the failed module may be retaken after 30 days.” — Appendix II to Part-66, point 1.11

Does the UK examine the same syllabus?

No. Regulation (EU) 2023/989 does not apply in the UK, and the assimilated UK Appendix I still carries Module 9A running 9.1 to 9.9, ending at hazards in the workplace, with an essay question in the examination. A candidate aiming at a UK CAA licence studies the nine-topic module; a candidate aiming at an EASA licence studies the ten. The divergence is the same story as Module 10 after 2023/989, and our certificates guide covers what the split means for recognition.

Where can you take Module 9 online?

The syllabus above is the knowledge the Part-66 examination tests; the examination itself is sat with a Part-147 organisation or the competent authority. MOST.AERO’s Part-66 Module 9 human factors course online covers sub-modules 9.1 to 9.10 and, in the same seat, the initial Part-145 safety training under 145.A.30(e); it ends with a completion certificate and contains no examination. The companion page Part-66 Module 9 + safety training: one course, two duties explains who needs which.

Is Module 9 the same as Part-145 human factors training?

They share content and serve different masters. Module 9 is a licensing examination the individual passes once under 66.A.25; safety training including human factors under 145.A.30(e) is an organisational obligation with an adjustable syllabus and a two-year continuation cycle. Passing one does not discharge the other — the full comparison, including where the syllabi overlap, is in Module 9 vs Part-145 human factors training.

Related courses. Part-66 Module 9 human factors and safety training online course follows the ten Appendix I sub-modules alongside the Part-145 initial syllabus, and Part-66 Module 10 aviation legislation online course covers the other module Regulation (EU) 2023/989 reshaped.