EASA & UK CAA PART-66 · B1.1
Thirteen exams.One licence.
The licence changes everything: your pay, your title, your options. The exams are the only thing in the way. Prep66 removes the guessing: you practise until ready isn’t a feeling, it’s a fact.
Nothing you’ll sit is missing.
The table lists every module and how many questions the bank holds for it. The bank is written to both the EASA and UK CAA syllabuses.
- M1Mathematics1,161
- M2Physics1,203
- M3Electrical Fundamentals1,354
- M4Electronic Fundamentals660
- M5Digital Techniques / EIS2,244
- M6Materials & Hardware2,301
- M7AMaintenance Practices5,084
- M8Basic Aerodynamics1,571
- M9AHuman Factors1,885
- M10Aviation Legislation963
- M11ATurbine Aeroplane Structures & Systems3,782
- M15Gas Turbine Engine2,565
- M17APropeller761
| Item | Description | Questions |
|---|---|---|
| M1 | Mathematics | 1,161 |
| M2 | Physics | 1,203 |
| M3 | Electrical Fundamentals | 1,354 |
| M4 | Electronic Fundamentals | 660 |
| M5 | Digital Techniques / EIS | 2,244 |
| M6 | Materials & Hardware | 2,301 |
| M7A | Maintenance Practices | 5,084 |
| M8 | Basic Aerodynamics | 1,571 |
| M9A | Human Factors | 1,885 |
| M10 | Aviation Legislation | 963 |
| M11A | Turbine Aeroplane Structures & Systems | 3,782 |
| M15 | Gas Turbine Engine | 2,565 |
| M17A | Propeller | 761 |
| Total | 13 papers, one licence | 25,534 |
EASA and the UK CAA set four of the thirteen papers differently: M6, M8, M9A and M10. The two syllabuses differ in more modules than those four, and the bank covers both. Every question in it is multiple choice with three options, like the papers; the essay parts of M7A, M9A and M10 are not covered. Part of each module’s bank is held back from practice: those are the questions the three mock papers for that module are built from, and each one joins your practice only once you have sat the paper it belongs to.
Don’t take our word for it. Answer one.
Two real questions from the Module 15 bank, exactly as set: one multiple choice and one Fill-in-the-Gaps. Switch format and have a go.
Multiple choice
Three options with one right answer, written like the real paper.
Fill-in-the-Gaps
A word or a short term you type from memory, with nothing to pick from.
Never just a mark
Every multiple choice question comes with a written explanation of its answer. Every gap shows you the completed sentence and where in the book it comes from.
What would happen if all dilution air entered at the fuel nozzle?
The component that slows compressor-delivery air before the primary zone is the .
The syllabus, condensed for revision.
One for every module, covering the same ground as the study books. The traps are flagged, and every place EASA and the UK CAA differ is marked.
Secondary, dilution, and cooling air
What each downstream air stream does after the primary flame.
- Secondary zone. Secondary holes admit more oxygen after the primary flame. This air completes burning; consumes remaining fuel fragments and carbon monoxide; shapes the flame; and begins reducing local temperature peaks.
- Admitting a large dilution flow too early could quench the flame and raise unburned-fuel and carbon-monoxide emissions.
- Dilution zone. Large downstream holes mix cooler compressor air with the hot products.
- The aim is not merely a lower average temperature. It is an even temperature profile around the complete turbine-entry annulus.
- A hot sector can damage only a few nozzle guide vanes and turbine blades while the average cockpit indication remains within a broad limit.
- Liner film cooling. Cooling air enters through small holes, slots, or louvres and lies along the inner metal surface. The film separates the liner from the hottest gas.
- Some designs use double-wall passages; many fine transpiration holes, which distribute cooling air through a porous or closely perforated wall; or ceramic coatings.
- A blocked cooling hole can make a local hot patch. Repeated local overheating can cause oxidation; buckling; cracking; coating loss; burn-through.
Pressure loss and combustion efficiency
Why the chamber must lose some pressure, and how completely it burns its fuel.
- The chamber needs a pressure difference to drive air through swirlers, holes, and cooling passages.
- Some loss is necessary in every case. Too much loss wastes compressor work and leaves less expansion available for the turbine and nozzle.
- Combustion efficiency can approach 100% in favourable low-altitude operation and may be about 98% at altitude. These are broad illustrations. Actual efficiency depends on pressure, temperature, atomisation, chamber design, fuel, and operating point.
One reference gives a total-pressure loss of about 3% of chamber-entry pressure, another about 5% to 10%. Both are correct and close; be ready for either. The applicable engine data controls.
Book against a number, not a gut feeling.
Every answer updates your readiness score for that module. Three things feed it: how much of the bank you’ve covered, how often you get questions right, and your best mock score once you’ve sat one. They come out as one number, read against the paper’s own pass mark. It’s an estimate built from your own answers, not a prediction.
Practise where you choose
You pick the target: a whole module, or a single topic inside it. Fixed sets of 25 questions with no timer, so you can stop whenever you want. All Modules keeps up to four modules on your bench at once. One Module gives you the single module you picked, and you can switch it once in each billing period.
It adds up topic by topic
Every answer counts toward the part of the syllabus it came from, not just the module. A weak area shows as a weak area instead of hiding in the module score.
Sit timed mocks
Full length papers under exam conditions, marked straight away, with a written explanation for every question.
- M3Electrical FundamentalsREADY91%
- M8Basic AerodynamicsREADY87%
- M15Gas Turbine Engine72%
- M7AMaintenance Practices47%
05 WHY THIS EXISTS
Part-66 revision can feel like a grind. You’re working through huge amounts of material, trying to remember what actually matters, and still wondering whether you’re ready for the exam.
I built Prep66 because I’d sat these exams myself and knew there had to be a better way to prepare.
So Prep66 is built around one thing: helping you know what to revise, practise it properly, and walk into the exam knowing where you stand.
- 25,534QUESTIONS
Every question comes with a written explanation, all of them, not just some.
- TwoAUTHORITIES
Written to both the EASA and the UK CAA syllabuses. Where the two differ, we mark it instead of quietly picking one.
- OneSOURCE OF TRUTH
Every paper, level and topic is taken from the regulation itself, not copied out of another revision book.
One module, or all thirteen. You choose.
Sign up without a card and look around first. Pay when you are ready to study. Cancel anytime. See everything a plan includes.
Subscribe before 1 November 2026 and you keep the price you start on for as long as that plan runs. Changing plan later moves you to the price of the day. The price from that day is shown under each plan below.
One Module
£9.99/month
$12.99 USD · €11.99 EUR
FROM 1 NOVEMBER 2026
£19.99 GBP · $25.99 USD · €23.99 EUR
Everything for the one module you are sitting next. You pick it after you pay.
- One module of your choice
- Unlimited practice questions on it
- Unlimited Fill-in-the-Gaps on it
- Its 3 mock exams
- Its study book and revision guide in full
- Blurting on every item of its guide
- Its 3 revision games
- Progress on the module
- Switch module once each billing period
All Modules
£19.99/month
$26.99 USD · €23.99 EUR
FROM 1 NOVEMBER 2026
£29.99 GBP · $39.99 USD · €34.99 EUR
Everything you need for full Part-66 prep, across all 13 modules.
- Unlimited practice questions, all 13 modules
- Unlimited Fill-in-the-Gaps, all 13 modules
- All 39 mock exams, 3 per module
- Full revision guides, both authorities, differences marked
- Blurting on every guide, every item
- All 3 revision games on every module
- The full study library, all 13 books
- Progress on every module you study
- Cancel anytime
Enterprise
By arrangement
For Part-147 schools and maintenance organisations getting their mechanics licensed.
- Everything in All Modules, on each account
- Unlimited questions, all modules
- Unlimited Fill-in-the-Gaps, all modules
- All 39 mock exams
- Set up and billed by arrangement
Talk to us
Straight answers to the usual questions.
Prep66 Academy is an online exam preparation platform for the EASA and UK CAA Part-66 aircraft maintenance licence exams. It covers all 13 modules of category B1.1 with 25,534 questions, a written explanation behind every answer, Fill-in-the-Gaps, 39 timed mock exams, a study book and a revision guide for every module, Blurting, a mistakes review, a readiness score and three timed revision games. It is independent: not a Part-147 organisation, and not affiliated with EASA or the UK CAA.
Yes, any time from your account, with no email, no phone call and no one talking you out of it. You keep your plan to the end of the period you’ve paid for. After that your account, your answers and your progress all stay, and the modules lock again until you choose a plan.
No, and we’d rather say that up front than bury it. We don’t refund part of a month. You can sign up without a card and look round the whole workspace first: every module, its syllabus and the shape of every screen. And if you want to judge the material on one paper before committing to all thirteen, the One Module plan is there for that.
One Module opens everything on the module you pick: unlimited practice and Fill-in-the-Gaps, its three mock exams, its study book and revision guide in full, Blurting on every item, its three revision games, its mistakes review, and its Progress screen. You pick the module inside the app after paying, and you can switch it once in each billing period. All Modules opens the same on all 13 modules at once: 39 mock exams, every book and guide, the three games on every module, and Progress on every module you study. On either plan, Progress shows your readiness score recomputed week by week, a projection to your exam date, which topics are climbing or slipping, and which ones you once had right but haven’t seen for a while.
Yes. On our reading of the regulation, the exams are open to you whatever your experience; you only need it later, when you apply for the licence itself. Sitting the papers while the theory is fresh is a perfectly sensible order to do it in.
Not for the exams. Experience counts towards the licence application, not towards whether you can sit a paper. What it changes is where you start: you choose the module, or a single topic inside it, so you can work from what you already know rather than from page one.
No, and we say so plainly. This is independent exam preparation for aircraft maintenance engineers. You must sit your exam with a competent authority or an approved Part-147 organisation. We prepare you for that paper; we don’t award anything ourselves.
Every question is multiple choice with three options, the Part-66 format, exactly as the paper sets it. Question weighting, knowledge level (1/2/3) and the style of the wrong options follow the EASA Part-66 Appendix I/II structure. Nothing is copied from live papers, because that would be both illegal and useless to you.
Both. The module structure is the same under both authorities, and four papers are set differently between them: M6, M8, M9A and M10 vary in question count, time allowed, or whether an essay is attached. Each module’s page shows both versions side by side. Where the content itself differs there is one guide for each module, not two, and every place the two part ways is marked in the guide, so you can see what your authority examines and what the other one does instead, rather than trusting that something filtered it out of sight.
No. Nobody honestly can, and anyone who does is selling you something. What we can do is put you in front of the same question format under the same time pressure until your scores stop moving, and then tell you plainly where your readiness score sits against the pass mark.
Yes. Prep66 runs in any modern mobile browser, with nothing to install. It runs the same on a phone as on a laptop.