Part-66 Module 9: Human Factors

Module 9 runs from a general statement of what human factors means in maintenance to a named list of the ways maintenance goes wrong, and its ten topics move outward from the person to the organisation around them. General at 9.1 and human performance and limitations at 9.2, both at level 2, set the engineer up as something with a specification, and it isn’t a flattering one: your eyes can’t resolve a hairline crack under a torch held at the wrong angle, your ears lose half a spoken instruction beside a running APU, attention shortens across the back end of a night shift, and working memory won’t reliably carry a torque figure from the manual to the wrench without something written down.

Around that sit the conditions the work happens in. Social psychology at 9.3, the physical environment at 9.5 and tasks at 9.6 are the module’s level 1 rows, covering responsibility, motivation and the pressure of a team; noise, cold, poor light and confined spaces; and repetitive work and long stretches of visual inspection, all of which you describe rather than work with. Factors that affect performance at 9.4 climbs back to level 2, because fatigue, stress, time pressure and the effect of medication are what actually move a person’s performance on a given night, and the syllabus wants you able to apply that rather than just name it.

Communication at 9.7 and human error at 9.8 are the rows that name things a working engineer has already watched happen. Communication here means the written and spoken record that carries a task between people: the entry that says awaiting part and doesn’t say which part, the worksheet that records what was done but not what was left undone, the instruction called across a hangar that no document ever catches. Human error means the models that separate a slip from a lapse from a deliberate violation, the reason a good team can produce the same mistake twice, and what an organisation can do about that which telling people to be more careful can’t.

The last two topics are where the EASA table and the UK one stop agreeing. EASA finishes with safety management at 9.9 and, at 9.10, the Dirty Dozen and risk mitigation: the industry’s list of twelve named contributors to maintenance error, with complacency, distraction, norms and lack of assertiveness among them, and it hung on hangar noticeboards for years before it became a numbered line in the syllabus. The UK table has no 9.10 at all, and its 9.9 is hazards in the workplace: the same number, over a different subject.

All of it is examined in writing: under EASA that means the multiple choice paper alone, and the UK adds an essay, the only part of Module 9A that asks you to compose anything.

EASA’s sitting is 28 questions in 35 minutes; the UK CAA’s is 20 in 25, with a written answer to follow. The UK arrangement is the older of the two: the EU text set an essay in this module as well until Regulation (EU) 2023/989 took it out, so a UK candidate today sits very nearly the exam EASA used to set, while an EASA candidate answers more multiple choice and writes nothing. Which authority you’re booked with changes the shape of the sitting, then, and not only its length.

At 75%, EASA’s paper needs 21 correct answers and survives 7 wrong ones, while the UK’s needs 15 and survives 5. For a UK candidate, though, that allowance covers one part of an exam that has two, and the parts are judged on their own: the written answer carries a threshold of its own, and a comfortable multiple choice score contributes nothing towards clearing it. There are two gates here rather than one, no surplus passes between them, and the work that gets you through the first isn’t the work that gets you through the second.

ten rows under EASA and nine under the UK CAA, each with the level its authority sets against it. The UK column here is our reading of the assimilated text, not one that has been independently confirmed, and on that reading the two columns match all the way down, so the highlighted rows below mark differences of content rather than of depth. The row to slow down on is 9.9, which keeps its number and its position in both tables and swaps its subject between them, and 9.10 beneath it has no UK counterpart at all.

Yes, and it’s worth knowing before you revise. EASA sets 28 questions in 35 minutes and no essay, while the UK CAA sets 20 in 25 and adds one essay question, which makes this one of the papers a UK B1.1 candidate has to write prose for, alongside Module 7A and Module 10. The name differs as well: it’s Module 9 in the current EU text and Module 9A in the UK’s.

The two syllabuses match title for title most of the way down, then part company at the end: EASA runs to ten topics and the UK to nine. There’s no UK equivalent of 9.10, the Dirty Dozen and risk mitigation, and the UK’s ninth and final topic is “Hazards in the workplace” where EASA’s ninth is “Safety management”. Only one other title is worded differently, and harmlessly: EASA’s “Factors that affect performance” is the UK’s “Factors affecting performance”.

Topic 9.9 is the pair to be careful with, because from a distance nothing about it looks like a difference: same code, same position in the table, the same knowledge level as far as we read the UK text, and a different subject underneath. An EASA candidate revising the reporting and risk machinery of safety management and a UK candidate revising the hazards of a hangar floor are both reading the right thing for their own paper. Revising a UK sitting from an EASA syllabus list, or the reverse, is the specific way to get caught out by it.

The reason is the age of the two documents rather than any disagreement about the subject: the UK text is a copy of Part-66 as it stood when GB stopped following the EU regulation, and EASA has amended the annex since. Regulation (EU) 2023/989 is also what abolished the lettered modules on the EASA side, replacing 7A, 9A, 11A and 17A with a single table that separates the categories by column instead.

The wider split between the two authorities is on the EASA versus UK CAA page: mutual recognition, which licence to go for, and what happened to the conversion route.

This page covers one of the 13 papers. The rest of the guide covers the route they sit inside: what the exam is, what else you must have done besides passing it, and how the two authorities differ.

Both authorities require the same thirteen subjects. Only the numbering and some of the titles differ, and the UK still uses the A suffix on four of them where EASA has dropped it. Each has a page of its own.