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EASA Part-66 Module 6 Cats A · B1 · B2 · B2L · B3

Materials & Hardware EASA Part-66 — Module 6 Practice Questions

Module 6 covers the metals, composites, fasteners and hardware that hold an aircraft together — ferrous and non-ferrous alloys, corrosion, rivets, bolts, pipes, bearings and electrical cables. Below: what each sub-section examines, the exam format per licence category, and seven sample questions in the same style you'll see on exam day.

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Every question comes with a worked, EASA-grounded explanation — understand why, don't just memorise.
1 209
Questions in bank
5
Syllabus sections
100 min
Exam time (B1/B2)
75 %
EASA pass mark

Syllabus at a glance

Full Module 6 syllabus
Section 6.1
Ferrous Materials
  • Carbon & alloy steel identification
  • Heat treatment: hardening, tempering & annealing
  • Hardness, tensile, fatigue & impact testing (B1 KL 2)
Section 6.2
Non-Ferrous Materials
  • Aluminium, magnesium, titanium & copper alloys
  • Alclad, duralumin & casting alloys
  • Solution treatment & precipitation hardening (B1 KL 2)
Section 6.3
Composites & Corrosion
  • Composite & non-metallic materials, sealants & bonding agents
  • Wooden structures & fabric covering (Cat A / B1 only)
  • Galvanic, intergranular, stress & exfoliation corrosion
Section 6.5
Fasteners & Hardware
  • Screw threads, forms, pitch & measurement
  • Bolts, nuts, studs, machine screws & self-tapping screws
  • Locking devices, split pins, wire locking & circlips
  • Solid & blind rivet types, specifications & identification
Section 6.6
Pipes, Bearings & Cables
  • Rigid & flexible pipes, unions & standard connectors
  • Springs, bearings & transmission components (B1+)
  • Control cables, turnbuckles & Bowden cables
  • Electrical cables, coaxial, crimping & connectors

Three classic exam-day traps

Tempering vs annealing temperature

Both relieve internal stress, but tempering is done below the annealing temperature to retain hardness. Candidates routinely tick "at" or "above" and lose the mark.

Galvanic vs intergranular corrosion

Galvanic (electrolytic) corrosion needs two unlike metals plus an electrolyte. Intergranular is caused by improper heat treatment. Question stems often blend the two — read carefully.

Diameter, lead & pitch on threads

On a single-start thread the lead equals one pitch; on a two-start thread the lead is twice the pitch. Confusing lead with pitch on multi-start fasteners is the classic 6.5.1 trap.

What Module 6 covers — in plain English

Module 6 of the EASA Part-66 syllabus covers every category of physical material and hardware item an aircraft maintenance engineer handles in the hangar — from the carbon and alloy steels in a landing-gear leg, through the aluminium and titanium that make up the airframe, to the rivets, bolts, lockwire, bearings and electrical connectors that fasten everything together. It is one of the broadest modules in the syllabus, with sixteen distinct sub-sections, and the questions test both material identification and the practical engineering rules that govern when each material or fastener is appropriate.

The bulk of marks fall in three areas: corrosion (galvanic action, intergranular, exfoliation, stress corrosion and the conditions that cause each), fasteners (thread forms, bolt & nut identification, locking devices and rivet specifications), and the heat-treatment processes applied to ferrous and non-ferrous alloys — hardening, tempering, annealing, solution treatment and precipitation (age) hardening. Wooden structures and fabric covering are also examinable, but only for Category A and B1 candidates working on legacy or light aeroplanes.

Knowledge levels vary widely across the sub-sections. Corrosion (6.4) is examined at level 3 for B1 — the highest in the module — meaning candidates must be able to apply theoretical knowledge and describe practical procedures. Most other sub-sections sit at level 2 for B1/B3 and level 1 for B2/B2L, with the notable exception of electrical cables and connectors (6.11), which is level 2 for every category. The full per-section breakdown is on our Module 6 syllabus page.

These samples are drawn from our live Module 6 question bank of 1 209 questions. The full timed practice quiz draws 80 questions per attempt (or 52 for Cat A), scored against the official EASA 75 % pass mark, with weak-area tracking across attempts.

7 free sample questions

Click "Reveal answer + explanation" after you've picked.

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Q1 Ferrous Materials · Heat Treatment

What temperature would steel be tempered at?

  1. A At the annealing temperature.
  2. B Above the annealing temperature.
  3. C Below the annealing temperature.
Reveal answer + explanation Hide answer
Correct answer: C — Below the annealing temperature.
Tempering follows hardening and is carried out below the annealing temperature (typically 150–650 °C, depending on the steel). Heating to or above the annealing point would undo the hardening process and leave the steel soft.
Q2 Non-Ferrous · Identification

What chemical is used to identify aluminium alloys?

  1. A Caustic soda.
  2. B Copper sulphate.
  3. C Nitric acid.
Reveal answer + explanation Hide answer
Correct answer: A — Caustic soda.
A drop of caustic soda (sodium hydroxide) on an aluminium alloy produces a characteristic dark stain whose colour depends on the alloying elements — used for field identification when the part number is missing or illegible.
Q3 Non-Ferrous · Casting Alloys

Which of the following metals is an aluminium silicon alloy used mainly for casting?

  1. A Alclad.
  2. B Aldrey.
  3. C Alpax.
Reveal answer + explanation Hide answer
Correct answer: C — Alpax.
Alpax is an aluminium-silicon casting alloy with good fluidity and corrosion resistance. Alclad is a pure-aluminium clad over an alloy core (sheet, not casting); Aldrey is an aluminium-magnesium-silicon alloy used for electrical conductors.
Q4 Corrosion · Galvanic

Corrosion caused by electrolytic action is the result of

  1. A contact between two unlike metals.
  2. B excessive anodization.
  3. C the wrong quenching agent.
Reveal answer + explanation Hide answer
Correct answer: A — contact between two unlike metals.
Electrolytic (galvanic) corrosion requires two dissimilar metals in electrical contact plus an electrolyte (usually water with dissolved salts). The less-noble metal becomes the anode and corrodes preferentially — which is why steel fasteners in aluminium structures need insulating washers.
Q5 Fasteners · Screw Threads

Most commonly used thread form in aviation is

  1. A V thread.
  2. B round thread.
  3. C buttress.
Reveal answer + explanation Hide answer
Correct answer: A — V thread.
The V thread (60° flank angle — UNC/UNF/Metric ISO) dominates aircraft fastener applications because the angled flanks distribute load well and resist loosening. Round threads are used on light-bulb caps; buttress threads carry axial load in one direction (e.g. breech blocks).
Q6 Fasteners · Rivets

How is a British aluminium rivet identified?

  1. A Black anodic finish.
  2. B Natural anodised finish.
  3. C Violet anodic finish.
Reveal answer + explanation Hide answer
Correct answer: A — Black anodic finish.
British aluminium rivets are anodised black for identification. Don't confuse with American colour codes (e.g. AN470AD = green) — the European and US rivet identification systems use different schemes and questions can test either.
Q7 Pipes & Unions · Flexible Hoses

How are flexible hoses categorised?

  1. A By maximum pressure.
  2. B By diameter.
  3. C By length.
Reveal answer + explanation Hide answer
Correct answer: A — By maximum pressure.
Flexible aircraft hoses are classified by their maximum operating pressure — typically low (under 250 psi), medium (up to 1500 psi) and high (above 3000 psi). Diameter and length are dimensions of a specific part number, not the classification of the hose type itself.
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Module 6 — frequently asked questions

How many questions are in the EASA Part-66 Module 6 exam?
The Module 6 (Materials & Hardware) multiple-choice exam has 52 questions for Category A and 80 questions for Category B1. The counts differ because B1 is examined to a greater depth across the module's sixteen sub-sections. Both papers are multiple-choice with a single correct answer per question.
What is the pass mark for EASA Part-66 Module 6?
The pass mark is 75%, the same as every EASA Part-66 module. You must reach 75% correct across the whole paper — there is no separate pass threshold per sub-section. Because the module is broad, a strong performance in your best areas can offset weaker ones as long as the overall total clears 75%.
How long is the Module 6 exam?
Category A candidates get 65 minutes for their 52 questions, and Category B1 candidates get 100 minutes for their 80 questions. Both allow 75 seconds per question, so the pace is the same — steady rather than rushed, with time to re-read stems that blend two similar concepts.
Which EASA licence categories require Module 6?
Module 6 is required for Cats A, B1, B2, B2L and B3 — it is one of the common modules that every licence category must pass. The depth of examination varies: mechanical categories such as B1 study fasteners, heat treatment and corrosion to a higher level, while avionics categories cover the same syllabus at a lower knowledge level. You can review the full breakdown on our Module 6 syllabus page.
What does Module 6 cover, and what do students find hardest?
Module 6 covers ferrous and non-ferrous metals, composites and corrosion, fasteners and hardware, and pipes, bearings and cables — every category of physical material and hardware item an engineer handles in the hangar. The heaviest marks fall on corrosion (galvanic, intergranular, exfoliation and stress corrosion), fasteners (thread forms, bolts, locking devices and rivet identification), and heat-treatment processes. Common trip-ups: candidates forget that tempering is done below the annealing temperature to retain hardness, confuse galvanic corrosion (two unlike metals plus an electrolyte) with intergranular corrosion (improper heat treatment), and mix up lead and pitch on multi-start threads. Reading question stems carefully is essential because they often blend two similar concepts.
How should I revise for Module 6?
Work section by section — the syllabus splits into ferrous materials, non-ferrous materials, composites and corrosion, fasteners and hardware, and pipes, bearings and cables — and drill the areas that carry the most marks first: corrosion, fasteners and heat treatment. Pay particular attention to the classic traps: tempering sits below the annealing temperature, galvanic corrosion needs two unlike metals plus an electrolyte (intergranular comes from improper heat treatment), and on a single-start thread the lead equals one pitch while on a two-start thread the lead is twice the pitch. Practising exam-style questions that deliberately blend these concepts is the fastest way to stop losing easy marks to misread stems.
Can I practise in a language other than English?

Yes. Every quiz question, all of its answer options and the written explanation can be read in 13 languages besides English — Chinese (Traditional), French, German, Greek, Hindi, Italian, Norwegian, Polish, Portuguese, Romanian, Russian, Spanish and Turkish. It is included for every signed-in member at no extra cost, and you can switch language in the middle of a quiz without losing your answers or your timer.

The English original stays one click away on every question, which is the point: the EASA Part-66 examination is sat in English, so you can read a question in your own language, answer it, then switch it back to English to check yourself against the wording you will actually meet.

Two caveats worth knowing. It is machine translation — checked so that no two answer options drift into meaning the same thing and that numerals and units survive intact, but it is not a human technical translation. And technical designations such as A320, LEAP-1A, Part-145, CS-25 and ATA chapter numbers are deliberately left in English, because those are the strings on the aircraft, in the manual and on the exam paper. Translation covers the quizzes; the study notes and reference pages are in English.

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10. Aviation legislation
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11. Aeroplane aerodynamics, structures and systems
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15. Gas turbine engine
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Module 6 study resources

Module 6 detailed syllabus
Per Commission Regulation (EU) 2023/989
Module 6 study notes
Topic-by-topic explanations
Q&A Forum
Ask about tricky Module 6 questions
EASA licence categories
A · B1 · B2 · B2L · B3 overview

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