EASA Part66
Module 3
Cats A · B1 · B2 · B2L · B3
Electrical Fundamentals EASA Part66 — Module 3 Practice Questions
Module 3 covers the electrical theory that underpins every system on a modern aircraft — from electron flow and Ohm's Law through DC and AC circuits, magnetism, transformers and motors. Below: the 18 sub-sections, exam format for each licence category, and seven sample questions in exam style.
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What Module 3 covers — in plain English
Module 3 of the EASA Part66 syllabus is the electrical theory foundation every licensed aircraft maintenance
engineer builds on for the rest of their career. It runs from the structure of the atom all the way through
DC and AC circuit analysis, magnetism, transformers and motor theory — eighteen sub-sections in total. Almost
every later module touches it: Module 4 (Electronic Fundamentals) assumes you already understand voltage,
current and resistance; Module 7 (Maintenance Practices) uses Ohm's Law on every wiring calculation; and the
airframe modules constantly refer back to electrical generation, distribution and motor control. Examiners
know this is foundational material, so the questions are pitched as applied calculations as
much as recall — expect to convert units, manipulate formulas and identify the correct law to invoke before
you can pick an answer.
The exam itself is one of the longer Part66 papers. B1, B2 and B2L candidates sit a 52-question paper
in 65 minutes, while B3 candidates sit a 24-question paper in 30 minutes and Category A candidates
sit 20 questions in 25 minutes. Time pressure is real — that's roughly 75 seconds per question for the longer
papers, and a typical Module 3 question requires a unit conversion or a two-step calculation before you can
even identify the right answer. The pass mark is 75 % across all categories, and like every Part66 paper
there is no negative marking — but with the calculator allowed only for arithmetic (not symbolic algebra),
candidates who haven't drilled the standard formulas to muscle memory tend to run out of time.
Knowledge depth varies sharply between licence categories. Category A and B3 candidates need only
level 1 (basic familiarisation) across the whole syllabus — recognising the principle and
naming the components. B1, B2 and B2L candidates need level 2 (general knowledge plus the ability to
apply principles) on almost every sub-section except 3.1 (Electron Theory) and 3.4 (Generation of
Electricity), which sit at level 1 for everyone. The biggest jump for B1/B2/B2L candidates is in capacitor,
inductor and AC-circuit analysis (3.9, 3.11 and 3.14) where numerical calculations are explicitly examinable.
B2 avionics candidates also tend to find sub-sections 3.15 (Transformers) and 3.16 (Filters) heavier going than
their B1 colleagues, simply because the underlying maths is closer to electronic-circuit analysis than to
airframe systems. Full knowledge-level breakdown by sub-section is on our
Module 3 syllabus page.
These samples are drawn from our live Module 3 question bank of 1 242 questions. The full
timed practice quiz draws 52 questions per attempt (or 20 for Cat A), scored against the official EASA 75 % pass mark, with weak-area tracking across attempts.
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Ready for the full Module 3 timed practice quiz?
Sign up, pick Module 3 from the dashboard, and take a timed exam drawn from our
1 242-question bank — the number of questions follows your licence category (20 for Cat A,
52 for B1/B2/B2L/B3). Your score is tracked across attempts and we surface
your weakest sub-topics so revision time pays off.