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Structural learning for the aircraft maintenance licence. The Part-66 syllabus is split into 307 chapters, and everything here follows it: read the study note, drill that chapter, and the Intelligent Progress Center shows you which chapter to study next.
No account needed for the 10-question sample quiz.
Module 3 — Electrical Fundamentals
A capacitor stores energy in an electric field between two conductive plates separated by an insulator (dielectric). Capacitors are found throughout aircraft systems — in power supply filtering, radio tuning circuits, timing circuits, and surge protection.
Module 3 — Electrical Fundamentals
Electricity can be generated by several different methods, each converting a different form of energy into electrical energy. Aircraft systems exploit many of these methods — from generators (magnetism) and thermocouples (heat) to piezoelectric sensors (pressure).
Module 3 — Electrical Fundamentals
This section defines the fundamental electrical quantities and their units. A clear understanding of voltage, current, resistance, and related concepts is essential before studying circuits, components, and systems in the remaining sections of Module 3.
Module 3 — Electrical Fundamentals
Static electricity deals with electric charges at rest, as opposed to current electricity where charges flow continuously. Static build-up on aircraft can damage sensitive electronics, cause radio interference, and even pose ignition hazards during refuelling.
Module 3 — Electrical Fundamentals
Electron theory explains the fundamental nature of electricity by examining atomic structure and the behaviour of electrons. This section lays the groundwork for understanding how electrical current flows and why different materials conduct electricity to different degrees.
The exam is written against syllabus paragraphs, so that is how everything here is organised. The note you read, the questions you drill and the progress we measure all carry the same reference.
18 chapters · 1,266 questions · 18 study notes
+ 14 more chapters in Module 3. See every module's syllabus
A study note written to that syllabus paragraph, with worked examples, key formulas and warnings. Read it, or watch it as narrated slides.
10, 20 or 30 questions from that chapter only, or a set of chapters you pick. A bad run never dents your module average.
Each question explains the right answer the moment you choose. Your mistakes go to Weak Areas, so they come back until you get them right.
The Progress Center ranks your weakest chapters, tracks readiness per module and counts down to your exam dates. Then sit a timed mock exam for your licence category.
It reads every answer you give and ranks your weakest syllabus chapters by how sure the evidence is, so eight answers at 50% outrank one unlucky question.
Exam Ready = 90% or more across five or more quizzes
Questions answered per day
Share of answers · accuracy
A large share of your effort went to Module 8, which is already exam-ready at 92%.
Sample data. Yours appears after your first quiz, and chapter-by-chapter guidance after about three.
Written paragraph by paragraph against the syllabus, so each note matches one chapter and opens that chapter's drill. Watch turns the note into narrated slides, section by section, and new illustrations show what the text describes.
296 notes across 17 modules. Pick a module to see its notes.
All 18 EASA Part-66 modules, plus UK CAA Module 10 written to UK law. Open a module for its syllabus, sample questions and the exam format for each licence category.
1,048 questions
996 questions
1,266 questions
874 questions
1,094 questions
1,208 questions
1,553 questions
1,075 questions
749 questions
691 questions
536 questions
2,523 questions
1,300 questions
1,716 questions
660 questions
1,369 questions
507 questions
803 questions
400 questions
Not sure where to start?Pick your licence category above, or take the free readiness check.Start free. Every plan covers every licence category.
€25 for six months, €45 for a year (€3.75 a month)
Offline PDF books €299.99
Aircraft type banks €39.99 each
Practice questions organised by ATA chapter, with worked answers and timed practice.
Every type is also a PDF question bank, €39.99. See the PDF banks
For licensed engineers: certificated courses mapped to the AMC, €39.99 a course.
Human Factorsincl. SMS, all staff
Fuel Tank SafetyCDCCL, Phase 1 + 2
EWISTarget Groups 1-2
Information SecurityPart-IS, all staff
Each course ends with a certificate. See all courses and bundles
Essay practiceModules 7, 9 and 10 are examined by essay. Write against the 20-minute clock and get it marked against the examiner Key Points.
Practise in your own languageQuestions, options and explanations in 13 languages, with the English original one click away.
All EASA module content aligned with Commission Implementing Regulation (EU) 2023/989 and (EU) 2025/111, which added Module 18 and subcategory B1.E from 13 February 2026. UK CAA Part-66 candidates: the 75% pass mark and question format are the same, but the UK still examines to its 2020 syllabus text, and Module 10 differs. UK CAA vs EASA. UK candidates can practise UK CAA Module 10, written to UK law, next to the 18 EASA modules. Valid prep for Australia's CASA Part 66 self-study exams too.
Borescope inspection allows visual examination of compressor blades, combustion liners, and turbine blades without engine disassembly, via built-in access ports.From Module 15Gas turbine engine
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At least 50 quizzes across 5 modules. Full rankings
Part-66 is Annex III to Regulation (EU) No 1321/2014. It sets the aircraft maintenance licence and its categories: A, B1, B2, B2L, B3 and, since 13 February 2026, B1.E. Each category requires a set of the 18 modules, and each module has its own exam with a 75% pass mark.
20,368 questions across the 18 EASA Part-66 modules and UK CAA Module 10, plus 25,427 aircraft type-rating questions. Every question shows an explanation when you answer it.
Modules 7, 9 and 10 include a written essay. Essay Practice gives you the 20-minute clock and marks your answer against the examiner Key Points, each one covered or missed.
Studying the Part-66 syllabus in its own structure: module, then chapter, then paragraph. Here the study note, the chapter drill and the Progress Center all use the same syllabus reference, so you always know which chapter a gap belongs to and what to do next.
The 75% pass mark and question format are the same, but the UK still examines to its 2020 syllabus text and Module 10 differs. UK candidates can practise a separate UK CAA Module 10 written to UK law.
An account is free. A subscription for every question bank is €5 for one month, €25 for six months or €45 for a year. Study notes are €99.99 for a year of online access, and the PDF question bank is €99.99 one-time.
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