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EASA Part-66 Exam Preparation
UK CAA Part-66 Compatible Australia CASA Part 66
Updated to EU 2023/989
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EASA Part-66 Exam Preparation Online

Practice with thousands of EASA Part-66 exam questions across all 17 modules, track your progress, and join a community of aviation maintenance engineers preparing for their licence. New to it? Read what EASA Part-66 is — the licence, modules and exams explained.

Every question explained: all 17,000+ EASA Part-66 questions come with a clear, regulation-grounded explanation shown the moment you answer — so you understand why, not just memorise the answer.

All content aligned with the latest Commission Implementing Regulation (EU) 2023/989 — covering categories A, B1, B2, B2L and B3. Also fully applicable to UK CAA Part-66 candidates — the UK keeps the same Part-66 modules, exams and 75% pass mark under UK Regulation (EU) No 1321/2014. UK CAA vs EASA → Valid prep for Australia's CASA Part 66 self-study exams too. CASA vs EASA →

Part-66 worldwide: the same module-based study also prepares you for Part-66-aligned exams in the UAE (GCAA CAR-66), Qatar (QCAR Part-66), Singapore (SAR-66), Hong Kong (HKAR-66) and India (DGCA CAR-66) and Kenya (KCAA), plus where EASA / UK-CAA Part-66 exams are sat locally in Egypt (ECAA) and Nigeria (NCAA).

Aircraft Type Training: practice question banks for the Airbus A320 (CEO & NEO), A220 and A330 and Boeing 737NG, 737 MAX and 787, organised by ATA chapter with worked answers and timed practice.

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Fact of the Day

11. Aeroplane aerodynamics, structures and systems

The speed of sound depends only on temperature: ~661 knots at sea level (288 K) but ~573 knots at 36,000 ft (217 K).

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Recent Q&A Activity

M

B. 4 3/8 is mixed number, means 4 + 3/8 and not 4 times 3/8, so 35/8 - 9/4 + 1/5 = 175/40 - 90/40 + 8/40 = 93/40 = 2 13/40.

Marek_AME replied to erik.daros.mac's question ·6h ago

E

Non è chiara la spiegazione, la notazione delle frazioni improprie è sbagliata

erik.daros.mac asked a question ·18h ago

E

Non si capisce il problema. Il punto B da quale parte della riva è? dalla parte dove devo arrivare o dove sono?

erik.daros.mac asked a question ·18h ago

P

Thank you for the report. You are right that the wording was ambiguous, and the stem has been corrected. The marked answer stands. What the question was describing is a nozzle at its design condition, with the throat choked and the exit flow supersonic. The gas arrives subsonic, accelerates through the converging section to reach Mach 1 at the throat, and then keeps accelerating through the diverging section as the now supersonic flow expands. Your reading was the reasonable one to take, and it is exactly why the stem needed changing. The area effect reverses either side of Mach 1: a converging duct accelerates subsonic flow, but it decelerates flow that is already supersonic. So on your reading of the old stem none of the three options would have been correct, which makes the wording a real defect rather than a matter of taste. Elsewhere in the bank that distinction is made explicit, with separate items keying air that enters a converging duct at sonic speed as decelerating. The st…

PART66Online replied to ewanroles13's question ·3d ago

E

The wording of the question suggests the airflow is supersonic before reaching the convergent-divergent nozzle

ewanroles13 asked a question ·3d ago

H

La doublure abradable est connue en nid d'abeille, en résine synthétique ou en plastique qui réduit le bruit. Il est fait également pour être poncé par les ailette de compresseur afin d'évité un espace.

hugohoarauhoarau replied to bucks's question ·4d ago

P

Thank you for the feedback. The marked answer is correct here, and it is worth setting out why. Leaning at high power does not take the engine straight to lean of peak. Coming back from full rich, the mixture first passes through the best power and peak cylinder head temperature region, and that is where the detonation margin collapses. The excess fuel that was providing charge cooling at full rich is no longer there, flame speed falls, and combustion carries further into the stroke. That is the condition this question describes, and it is why the operating procedures for most certified engines call for full rich above roughly 75 percent power. You are correct that well lean of peak brings cylinder head temperatures back down. That is a real technique, but it depends on fuel distribution good enough to support it, and it is not a high power setting, so it sits outside what this question is asking. Of the three options given, reduced fuel flow is a cause rather than a result, and oil…

PART66Online replied to jon@efm.ltd's question ·9d ago

J

This question is worded badly. If the mixture is set lean of peak, the cylinder head temperature will decrease, NOT increase. "too lean" is very ambiguous. Please be more precise in the wording!

jon@efm.ltd asked a question ·9d ago

S

Actually, option 1 is not incorrect due to missing keywords, it is incorrect due to scope. It limits the aim to occupational health and accident prevention, whereas a human factors programme addresses the interaction of personnel with equipment, procedures and environment, and therefore targets operational safety and efficiency as well as personal well-being.

svenj88 replied to wan.yc.justin's question ·16d ago

W

#1 being wrong is it because of the missing of keywords?

wan.yc.justin asked a question ·17d ago

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