Prep66Academy

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.

Start preparing See all 13 modules

NO CARD TO SIGN UP · PAY WHEN YOU START STUDYING

EXAMINATION BOARDB1.1 · 13 PAPERS
ITEMSUBJECTSTATUS
M15
GAS TURBINE ENGINE
REVISING
M7A
MAINTENANCE PRACTICES
REVISING
M3
ELECTRICAL FUNDAMENTALS
CLEARED
M11A
TURBINE AERO SYSTEMS
BOOKED
ONE MODULE OR ALL 13
MODULES
13all covered
QUESTION BANK
25,534
MOCK EXAMS
39
EXAM MINUTES
EASA sets 935 minutes of exams across the 13 papers. The UK CAA sets 945.
across all 13 papers
01 THE SYLLABUSSHT 01 · PART-66 APPX I

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.

Total13 papers, one licence25,534 questions

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.

02 THE PRACTICE

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.

M15 · GAS TURBINE ENGINE · Q.14/25PICK ONE
15.5 COMBUSTION SECTION · LEVEL 2

What would happen if all dilution air entered at the fuel nozzle?

03 THE REVISION GUIDES

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.

Module 15 Revision Guide15.5 COMBUSTION SECTION
SHEETS 99 AND 100 / 507
15.5.7

Secondary, dilution, and cooling air

What each downstream air stream does after the primary flame.

THE FACTS
  • 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.
99
15.5.8

Pressure loss and combustion efficiency

Why the chamber must lose some pressure, and how completely it burns its fuel.

THE FACTS
  • 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.
FORMULA
ηc=actual heat releasedtheoretical fuel heat available× 100%
FIGURES VARY

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.

100
04 THE METHODSHT 04 · READINESS SCORE

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.

  1. 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.

  2. 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.

  3. Sit timed mocks

    Full length papers under exam conditions, marked straight away, with a written explanation for every question.

EXAM READINESS · YOUR BENCH● 4 ON THE BENCH
72%M15 READINESS SCORE
  • M3Electrical FundamentalsREADY91%
  • M8Basic AerodynamicsREADY87%
  • M15Gas Turbine Engine72%
  • M7AMaintenance Practices47%
M15 · NEARLY THERENo mock sat yet, so this counts practice only

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.

DANTE LEONFOUNDER · BRITISH AIRWAYS AIRCRAFT MECHANIC
  • 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.

06 PRICING

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.

PRICES CHANGE ON 1 NOVEMBER 2026

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 PAPER AT A TIME

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
Choose One Module
BEST VALUEEVERYTHING OPEN

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
Choose All Modules
SCHOOLS & MRO

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
SCHOOLS & MRO ENQUIRIESsupport@prep66academy.com
07 QUESTIONS PEOPLE ASKSHT 07

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.

NO CARD TO SIGN UP · ONE MODULE OR ALL 13

Book it once.
Sit it once.