EASA Part66
Module 17
Cats A1 · A2 · B1.1 · B1.2 · B3
Propeller EASA Part66 — Module 17 Practice Questions
Module 17 covers propeller theory, construction, pitch control, synchronising, ice protection and maintenance — sat by piston-aeroplane and turboprop candidates (A1/A2, B1.1, B1.2, B3). Below: what's covered, exam format, and seven sample questions in the same style you'll meet on exam day.
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What Module 17 covers — in plain English
Module 17 of the EASA Part66 syllabus covers everything the licensed engineer needs to know about
propellers — from the blade-element aerodynamics that produce thrust through to the constant-speed
units, governors, ice-protection systems and balancing procedures that keep them serviceable. It is one
of the more practical modules: most of the failure modes you study here have a direct, visible counterpart
on the flight line, which is why section 17.6 (Maintenance) is examined at knowledge level 3
for B1.1, B1.2 and B3 candidates while everything else sits at level 2. Static and dynamic balancing,
blade tracking, blending damage and cropping limits all appear regularly in the question bank, and
unlike the more theoretical modules the wrong answers tend to look very plausible to anyone who hasn't
spent time on a hangar floor.
The bulk of the exam pressure comes from pitch control — speeder springs, flyweights,
on-speed/under-speed/overspeed conditions, feathering circuits, reverse pitch and the beta range. Many
questions hinge on small details: which way CTM and ATM try to move the blade, what holds the prop on the
fine-pitch stop, how the CSU governor reacts to a change in TAS, and which oil supply feeds the pitch
servo in single-acting versus double-acting designs. The synchronising and synchrophasing sections add
a second layer — distinguishing matched RPM from matched phase angle, and remembering that synchrophasing
uses pulse probes feeding a single phase-angle controller while basic synchronising only trims a slave
engine's governor to match the master. Ice-protection questions are simpler but catch candidates out
on the alcohol type (isopropyl, not ethyl or glycol) and on fast/slow cycle timing.
Module 17 only applies to candidates whose licence scope includes propeller-driven aircraft:
A1 and A2 (piston aeroplanes), B1.1 (turbine aeroplanes), B1.2 (piston aeroplanes) and B3
(piston aeroplanes ≤ 2000 kg). B2 avionics and B1.3/B1.4 helicopter candidates do not sit
this paper under the 2023/989 amendment (B1.3 was removed entirely, and the small B2 carve-out for
17.1/17.2 at level 1 was dropped). Candidates renewing from a pre-2024 licence should pay particular
attention to the new category split — A2 and B1.2 now sit at level 2 across all sections (previously
level 1), so the question style aimed at those candidates has shifted from pure recognition towards
applied understanding of the systems. The full per-section knowledge-level breakdown, including the
level-3 Maintenance carve-out and the storage/preservation section that's often skipped in revision,
is on our
Module 17 syllabus page.
These samples are drawn from our live Module 17 question bank of 802 questions. The full
timed practice quiz draws 32 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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Sign up, pick Module 17 from the dashboard, and take a timed exam drawn from our
802-question bank — the number of questions follows your licence category (20 for Cat A,
32 for B1/B2/B2L/B3). Your score is tracked across attempts and we surface
your weakest sub-topics so revision time pays off.