EASA Module 4
EASA Part-66 Module 4 - Electronic Fundamentals
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ExploreAbout this exam
EASA Part-66 Module 4, Electronic Fundamentals, is one of the knowledge modules that make up the theoretical training requirement for an aircraft maintenance licence under the European aviation maintenance training system. It sits alongside the other basic knowledge modules and is normally delivered by a Part-147 approved maintenance training organisation, either as a full course or as a bridging module for candidates extending an existing licence category. Because electronic systems now underpin almost everything on a modern aircraft - from engine control units and instrument displays to sensing and actuation loops - the module is written to give a maintenance technician a working understanding rather than a designer's depth. The syllabus is grouped into three broad areas: semiconductors, covering diodes, transistors, thyristors and integrated circuits together with their practical behaviour in circuits; printed circuit boards, covering construction, assembly, soldering and inspection practice together with typical defect recognition; and servomechanisms, covering open- and closed-loop control, feedback, position and rate sensing, and the behaviour of synchro and servo systems. Preparation is best built on a good basic electricity foundation, with plenty of practice on circuit symbols, simple fault diagnosis and schematic reading. Candidates should confirm the applicable syllabus, examination arrangements and licensing requirements with their national aviation authority or their approved training organisation, since EASA publishes the regulation itself rather than individual examination profiles.
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About EASA Module 4 preparation
What is EASA Module 4 actually for?
It is a basic knowledge module in the Part-66 aircraft maintenance licence syllabus, covering electronic fundamentals. Passing it demonstrates the electronic understanding expected of a certifying technician. It is usually studied as part of a Part-147 course or as a bridging module when adding a licence category, and the licence itself is issued by the national aviation authority.
Do I need to pass Module 4 for every licence category?
Not necessarily - the required module set depends on the licence category and on any previous qualifications you hold. Some categories require a reduced electronic fundamentals content. Ask your approved training organisation or national aviation authority for the module matrix that applies to your chosen category before you enrol.
What format is the examination?
Part-66 module examinations are normally multiple-choice, sat under invigilation at an approved organisation. EASA's regulation page does not publish an examination profile, so confirm the exact paper format, question count and time allowed with your training organisation or authority rather than relying on second-hand figures.
What is the pass mark and how long is the exam?
Pass marks and paper durations are set at national and organisational level and are not published on the EASA regulation page used for this page, so no figure is quoted here. Check your authority's or training organisation's candidate handbook before exam day; assuming a figure you found online is a common and avoidable mistake.
How long should I spend preparing?
There is no published study-hour figure for this module, so treat any number you see with caution. Realistically, allow enough time to work through each of the three areas - semiconductors, printed circuit boards and servomechanisms - and then to practise on schematic reading and simple fault-finding, which is where most marks are lost.
What order should I study the topics in?
Start with semiconductors, because diodes and transistors underpin everything else. Move to printed circuit boards once you can read a schematic and recognise components, since PCB work is largely about assembly, soldering and defect recognition. Finish with servomechanisms, which combine feedback theory with sensing and actuation and rewards a solid grasp of the earlier material.
What are the most common failure modes?
Weak fundamentals rather than weak memory. Candidates frequently confuse NPN and PNP behaviour, misread diode bias in a circuit, muddle open- and closed-loop control, or cannot identify a PCB defect from a description. Practise explaining circuits in your own words and diagnosing faults from symptoms instead of memorising component lists.
Can I retake the examination if I fail?
Retake arrangements are set by the examining organisation and the national authority; the EASA regulation page does not state a retake policy, waiting period or attempt limit, so none is quoted here. Ask your training organisation about their resit procedure, any waiting time and the fee before you sit the paper.
Is this page an official EASA resource?
No. This page is independent study material and is not affiliated with, endorsed by or published by EASA or any national aviation authority. The only official source referenced is Commission Regulation (EU) No 1321/2014, adopted 26 November 2014 and published in OJ L 362, 17.12.2014, p. 1, which you should consult for the regulation itself.