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100+ Free Module 12 Practice Questions

Pass your EASA Part-66 Module 12 - Helicopter Aerodynamics, Structures and Systems exam on the first try — instant access, no signup required.

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2026 Statistics

Key Facts: Module 12 Exam

75%

Pass Mark per Module

EASA Part-66

128 questions

B1.3/B1.4 Exam Length

EASA Part-66 Appendix II

160 minutes

B1.3/B1.4 Time Allowed

EASA Part-66 Appendix II

~75 seconds

Time per Question

EASA Part-66 examination standard

3 attempts

Maximum Consecutive Attempts

EASA Part-66 (90-day wait after the third fail)

12 June 2024

Regulation (EU) 2023/989 Applicable

Commission Implementing Regulation (EU) 2023/989

B1.3 / B1.4

Helicopter Licence Categories

EASA Part-66

EASA Part-66 Module 12 is the helicopter aerodynamics, structures and systems knowledge module for the B1.3 (turbine) and B1.4 (piston) aircraft maintenance licence categories, with a lighter syllabus for A3/A4. The B1.3/B1.4 exam is 128 multiple-choice questions in 160 minutes (A3/A4: 100 questions in 125 minutes), 3-option in the real exam, with a 75% pass mark and about 75 seconds per question. Content spans rotary-wing theory of flight (dissymmetry of lift, retreating blade stall, vortex ring state, Coriolis effect, autorotation, ground effect), flight control systems (cyclic, collective, anti-torque, swashplate, AFCS, fly-by-wire), blade tracking and 1/rev and n/rev vibration analysis, transmissions (main gearbox, freewheel units, rotor brake, tail rotor drive), airframe structures, and systems including air conditioning, electrical, fire protection, fuel, hydraulics, ice and rain protection, landing gear, lights and instruments. Candidates get a maximum of 3 consecutive attempts with a 90-day wait. The module follows Commission Implementing Regulation (EU) 2023/989, applicable 12 June 2024.

Sample Module 12 Practice Questions

Try these sample questions to test your Module 12 exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1In forward flight, the advancing blade of a single main rotor travels faster through the air than the retreating blade, producing unequal lift across the rotor disc. What is this phenomenon called?
A.Coriolis effect
B.Translating tendency
C.Dissymmetry of lift
D.Gyroscopic precession
Explanation: Dissymmetry of lift is the unequal lift across the rotor disc in forward flight, caused by the advancing blade having a higher relative airspeed than the retreating blade. It is compensated by blade flapping (and cyclic feathering).
2A helicopter is established in a high descent rate at low forward airspeed with power applied, and the pilot reports rising sink rate, increasing vibration and reduced cyclic authority. The rotor is descending into its own downwash. Which condition is this?
A.Retreating blade stall
B.Vortex ring state
C.Ground resonance
D.Dynamic rollover
Explanation: Vortex ring state (settling with power) occurs at high rate of descent, low airspeed and with power applied, as the rotor recirculates its own downwash; symptoms include increasing sink rate, vibration and loss of cyclic authority. Recovery is forward cyclic or lowering collective to fly out of the recirculating air.
3When a cyclic input is applied to a rotating rotor disc, the maximum displacement of the disc occurs approximately 90 degrees later in the direction of rotation than the point of input. This characteristic is a result of:
A.Coriolis effect
B.Conservation of angular momentum during coning
C.Translating tendency
D.Gyroscopic precession
Explanation: Gyroscopic precession causes a force applied to a spinning mass to manifest its effect approximately 90 degrees later in the plane of rotation. This is why pitch-change (feathering) inputs are mechanically phased ahead so the disc tilts in the intended direction.
4As an articulated rotor blade flaps upward, its centre of mass moves closer to the axis of rotation. To conserve angular momentum the blade tends to accelerate. What is this effect, which is accommodated by the lead-lag (drag) hinge?
A.Gyroscopic precession
B.Coriolis effect
C.Dissymmetry of lift
D.Phase lag
Explanation: The Coriolis effect causes a flapping blade to speed up (lead) as its mass moves inboard and slow down (lag) as it moves outboard, conserving angular momentum. Articulated heads provide a lead-lag hinge and dampers to accommodate this.
5Retreating blade stall is the primary aerodynamic limitation that establishes which helicopter performance boundary?
A.Maximum hover ceiling out of ground effect
B.Never-exceed forward speed (VNE)
C.Maximum gross weight
D.Minimum autorotation rotor RPM
Explanation: At high forward speed the retreating blade encounters low relative airspeed and a high angle of attack, eventually stalling; this sets the never-exceed speed (VNE), with symptoms of vibration, nose pitch-up and a roll toward the retreating side.
6During autorotation following a power loss, what provides the energy to keep the main rotor turning?
A.Residual torque stored in the freewheel unit
B.Stored hydraulic accumulator pressure
C.Upward airflow through the rotor disc as the helicopter descends
D.Tail rotor windmilling driving the main gearbox
Explanation: In autorotation the freewheel unit disconnects the failed engine and the upflow of air through the descending rotor disc drives the blades, maintaining rotor RPM. The disc divides into driven, driving and stall regions along the span.
7A single main rotor helicopter tends to drift laterally in a stable hover because of the thrust produced by the tail rotor. What is this tendency, and how is it commonly corrected by the designer?
A.Coning, corrected by increasing blade weight
B.Translating tendency, corrected by rigging the rotor mast or controls to a slight lateral tilt
C.Ground effect, corrected by raising the skids
D.Phase lag, corrected by advancing the swashplate
Explanation: Translating tendency (tail rotor drift) is the sideways drift caused by tail rotor thrust in the hover. Designers correct it by offsetting the mast/transmission, biasing the cyclic rigging, or raising one side of the gearbox so the disc is slightly tilted to oppose the drift.
8A helicopter hovering close to the ground requires less power than the same hover at altitude. The cushion of higher-pressure air beneath the disc that reduces induced drag and downwash is known as:
A.Vortex ring state
B.Translational lift
C.Ground effect
D.Coning
Explanation: Ground effect occurs when the rotor is within roughly one rotor diameter of the surface; the restricted downwash reduces induced velocity and induced drag, lowering the power required to hover.
9As a helicopter accelerates from the hover through about 16 to 24 knots, rotor efficiency suddenly improves and the aircraft tends to climb without an increase in power. This effect is called:
A.Power settling
B.Retreating blade stall
C.Ground resonance
D.Effective translational lift (ETL)
Explanation: Effective translational lift occurs as forward airspeed (typically about 16-24 kt) allows the rotor to work in cleaner, less turbulent air and the rotor leaves its own recirculating downwash, improving efficiency and producing extra lift.
10On the retreating side of the rotor disc in high-speed forward flight, a region near the blade root experiences airflow that strikes the trailing edge first. What is this region called?
A.Driving region
B.Stall region
C.Reverse flow region
D.Negative coning region
Explanation: The reverse flow region is the area near the root of the retreating blade where the blade is moving rearward more slowly than the forward airspeed, so air meets the trailing edge first. It grows with forward speed and contributes to the high-speed limits.

About the Module 12 Exam

EASA Part-66 Module 12 covers helicopter aerodynamics, structures and systems and is one of the knowledge modules required for the B1.3 (turbine helicopter) and B1.4 (piston helicopter) aircraft maintenance licence categories, with reduced syllabus depth for the A3/A4 categories. It examines rotary-wing theory of flight, flight control systems, blade tracking and vibration analysis, transmissions, airframe structures and the full range of helicopter systems. The real examination is multiple-choice (3-option), sat at a National Aviation Authority or an approved Part-147 organisation, with a 75% pass mark. The module reflects Commission Implementing Regulation (EU) 2023/989, applicable from 12 June 2024.

Questions

128 scored questions

Time Limit

160 minutes (B1.3/B1.4); 125 minutes for A3/A4 (100 questions)

Passing Score

75% per module

Exam Fee

Varies by NAA/Part-147 organisation (approx. EUR 50-230 per module sitting) (EASA framework - examinations conducted by National Aviation Authorities or approved Part-147 maintenance training organisations)

Module 12 Exam Content Outline

18%

Theory of Flight - Rotary Wing Aerodynamics

Torque reaction and directional control, gyroscopic precession and 90-degree phase lag, dissymmetry of lift and blade flapping, retreating blade stall setting VNE, translating tendency, Coriolis effect and lead-lag, vortex ring state and overpitching, autorotation regions, ground effect and effective translational lift

16%

Flight Control Systems

Cyclic and collective control via the swashplate and pitch links, anti-torque (yaw) control with conventional tail rotor, Fenestron and NOTAR, main rotor head types (articulated, semi-rigid teetering, hingeless), blade dampers, fixed/adjustable stabilisers, artificial feel, AFCS/SAS, fly-by-wire signalling and control rigging

14%

Blade Tracking & Vibration Analysis

Tracking the tip-path plane, span and chord balance, pitch-link and trim-tab adjustment for high/low blades, 1/rev lateral main rotor vibration versus high-frequency tail rotor vibration, n/rev blade-passing frequencies, magnetic-pickup azimuth reference and bifilar/anti-resonance vibration absorbers

14%

Transmissions

Main gearbox spiral-bevel and planetary reduction stages, sprag-type freewheel units enabling autorotation, twin-engine combining gearboxes, rotor brake limits, tail rotor drive shafts with hanger bearings and flexible couplings, intermediate and tail gearboxes, chip detectors and gearbox oil temperature/pressure monitoring

16%

Airframe Structures

Semi-monocoque fuselage and tail boom, firewalls of stainless steel/titanium and fire zones, composite rotor blades and honeycomb-sandwich panels, life-limited (safe-life) dynamic components, highly stressed blade attachment fittings, NDT methods (penetrant, magnetic particle, eddy current, tap testing) and equipment and furnishings for occupant restraint

16%

Aircraft Systems

Air-cycle and vapour-cycle air conditioning, DC/AC electrical power with inverters and TRUs, continuous-loop fire detection and halon-type extinguishing with discharge indicators, boost/transfer/cross-feed fuel and crash-resistant fuel systems, single and dual hydraulic systems with accumulators, thermal and electrical ice protection, skid/wheel/float landing gear, navigation and anti-collision lights and pneumatic/vacuum services

6%

Instruments & Avionics

Pitot-static instruments (airspeed, altimeter, VSI), gyroscopic attitude indicator using rigidity in space, torquemeter and low rotor RPM warning, radio altimeter for low-level operations, Integrated Modular Avionics (IMA), and HUMS and on-board maintenance fault-recording systems

How to Pass the Module 12 Exam

What You Need to Know

  • Passing score: 75% per module
  • Exam length: 128 questions
  • Time limit: 160 minutes (B1.3/B1.4); 125 minutes for A3/A4 (100 questions)
  • Exam fee: Varies by NAA/Part-147 organisation (approx. EUR 50-230 per module sitting)

Keys to Passing

  • Complete 500+ practice questions
  • Score 80%+ consistently before scheduling
  • Focus on highest-weighted sections
  • Use our AI tutor for tough concepts

Module 12 Study Tips from Top Performers

1Be able to distinguish the four classic rotary-wing effects examiners mix up: dissymmetry of lift (forward-flight lift imbalance), gyroscopic precession (90-degree phase lag), Coriolis effect (lead-lag) and translating tendency (tail rotor drift)
2Memorise the vortex ring state recipe - high rate of descent, low airspeed, power applied - and the recovery of forward cyclic or lowering collective; do not confuse it with retreating blade stall, which sets VNE at high speed
3Understand the freewheel (sprag) unit's role: it sits between the engine and main transmission and lets the rotor overrun for autorotation, while a separate rotor brake only stops the rotor on the ground below a specified RPM
4Separate track from balance: pitch-link/trim-tab adjustments correct vertical track (tip-path plane) and 1/rev vertical vibration, while weights correct span/chord balance and lateral 1/rev vibration; tail rotor faults give a higher-frequency vibration
5Learn the 75% pass mark and the 128-question/160-minute (B1.3/B1.4) format so you practise at about 75 seconds per question, and remember the real exam is 3-option even though this bank uses 4
6Know the system fundamentals: air-cycle versus vapour-cycle air conditioning, inverter (DC-to-AC) versus TRU (AC-to-DC), continuous-loop fire detection with thermal and crew discharge indicators, and oleo-pneumatic versus skid landing gear

Frequently Asked Questions

What is EASA Part-66 Module 12?

Module 12 is the helicopter aerodynamics, structures and systems knowledge module of the EASA Part-66 aircraft maintenance licence syllabus. It is required for the B1.3 (turbine helicopter) and B1.4 (piston helicopter) categories, with a reduced syllabus depth for the A3/A4 categories.

How many questions are on the Module 12 exam and how long is it?

For B1.3/B1.4 the exam is 128 multiple-choice questions in 160 minutes; for A3/A4 it is 100 questions in 125 minutes. The pace works out at about 75 seconds per question, and the pass mark is 75%.

Is the real Module 12 exam multiple-choice or essay?

Module 12 is multiple-choice only, with three options per question in the real exam. Essays were removed from Modules 9 and 10 in June 2024 and now remain only in Module 7. This free practice bank uses four options to give extra distractor practice.

What topics does Module 12 cover?

It covers rotary-wing theory of flight (dissymmetry of lift, retreating blade stall, vortex ring state, autorotation), flight control systems, blade tracking and vibration analysis, transmissions, airframe structures, and helicopter systems such as fuel, hydraulics, electrical, fire protection, ice and rain protection and landing gear.

What does Commission Implementing Regulation (EU) 2023/989 change?

Applicable from 12 June 2024, it merged former sub-module splits (for example 7A/7B into 7, 9A/9B into 9 and 11A/11B/11C into 11) and removed essays from Modules 9 and 10. Courses started under the old standard must be completed by 12 June 2026.

How many attempts do I get to pass Module 12?

Candidates may take a maximum of 3 consecutive attempts at a module. After a third unsuccessful attempt a 90-day waiting period applies before the next attempt, in line with EASA Part-66 examination rules.

Does Module 12 apply to UK CAA licences?

This practice bank is EASA-specific. Since Brexit the UK CAA Part-66 syllabus has diverged from EASA, so UK candidates should confirm their syllabus version with the CAA, though the underlying helicopter engineering principles are broadly the same.