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CAA NZ AME Aeroplanes 1 (Subject 4) study materials
CAA NZ AME Aeroplanes 1 (Subject 4) study resources

CAA NZ AME Aeroplanes 1 (Subject 4) practice questions

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Question 1Aeroplane airframe structures and systems

On a semi-monocoque aeroplane fuselage, what is the primary function of the stringers?

  1. They provide the attachment points for the wing spar carry-through structure
  2. They transmit engine thrust directly to the firewall
  3. They form the pressure-tight boundary of the cabin
  4. They carry the main bending loads along the fuselage length and stabilise the skin panels Correct answer.

Explanation

Stringers run longitudinally and, together with the skin, carry bending and shear loads while stiffening the skin against buckling between frames. Frames maintain the cross-sectional shape and pressure bulkheads seal the cabin, so those duties belong to other members. The wing carry-through is a separate reinforced structure.

Question 2Aeroplane airframe structures and systems

A wing spar that has been drilled and bolted during a repair shows a crack originating at a bolt hole and growing perpendicular to the principal tensile stress. Which failure mode does this describe?

  1. Fatigue cracking Correct answer.
  2. Stress corrosion cracking
  3. Intergranular corrosion
  4. Creep deformation

Explanation

Fatigue cracks initiate at stress concentrations such as fastener holes and propagate perpendicular to the principal tensile stress under cyclic loading. Stress corrosion requires a corrosive environment plus sustained tensile stress, and intergranular corrosion attacks grain boundaries without the characteristic cyclic growth pattern. Creep is time-dependent deformation at elevated temperature.

Question 3Aeroplane airframe structures and systems

In a typical light aeroplane wing, what structural role does the leading edge skin perform?

  1. It houses the main fuel tank and carries all fuel weight
  2. It transfers aileron hinge loads directly to the rear spar
  3. It carries the entire wing bending moment to the fuselage
  4. It carries torsional loads into the front spar and maintains the aerofoil shape Correct answer.

Explanation

The leading edge skin, often forming a D-nose with the front spar, contributes to torsional stiffness and preserves the leading-edge profile. Bending is carried mainly by the spar caps, and aileron loads go to the rear spar and its hinges.

Question 4Aeroplane airframe structures and systems

During a walk-around you notice that a bonded composite fairing has a dull, whitish area that does not disappear when wiped. Which condition should you suspect?

  1. Normal gel-coat weathering that needs no action
  2. A disbond or impact damage beneath the surface Correct answer.
  3. Static discharge damage from lightning
  4. Fuel staining from a leaking tank seal

Explanation

A persistent whitish or cloudy area on a composite surface can indicate a disbond, delamination, or impact damage where the resin has separated from the reinforcement. Weathering usually affects appearance uniformly and is removed or clarified by cleaning. Fuel staining and lightning strike marks have distinct appearances and locations.

Question 5Aeroplane airframe structures and systems

What is the purpose of a lightning diverter strip on a composite aeroplane structure?

  1. It bonds the structure to the electrical return network for avionics
  2. It provides a controlled conductive path so strike current is conducted away from critical structure Correct answer.
  3. It prevents galvanic corrosion between dissimilar metals
  4. It dissipates static electricity generated by airflow over the skin

Explanation

Diverter strips are conductive elements that give lightning current a defined path, reducing the risk of explosive delamination or puncture of composite structure. Static dischargers handle precipitation static, and bonding leads serve the electrical return network. Galvanic corrosion control is achieved by isolation and sealants.

Question 6Aeroplane airframe structures and systems

A pressurised fuselage is being inspected after a hard landing. Which area is most likely to show overstress around the pressure boundary?

  1. The stringer run-outs at the wing root
  2. The centre of large unstiffened skin panels between frames
  3. The lower skin of the unpressurised aft equipment bay
  4. The skin and frames adjacent to the pressure bulkhead and door cut-outs Correct answer.

Explanation

Pressure loads concentrate at discontinuities such as bulkheads, door and window cut-outs, and reinforced frames, so overstress and cracking are most likely there. Large unstiffened panels and unpressurised bays see lower pressure-related stress. Stringer run-outs carry bending loads but are not the primary pressure-boundary concern.

Question 7Aeroplane airframe structures and systems

What does the term 'fail-safe' mean when applied to aeroplane structural design?

  1. The structure will never develop any cracks in service
  2. The structure can sustain damage without catastrophic failure until the damage is detected Correct answer.
  3. The structure is designed so that no inspection is required
  4. The structure fails only at the ultimate design load

Explanation

Fail-safe design uses redundant load paths and crack-arrest features so that damage or failure of one element does not cause loss of the structure before detection. It does not mean cracks never occur, nor does it remove the need for inspection. Ultimate load capability is a separate strength requirement.

Question 8Aeroplane airframe structures and systems

Which material property is the main reason high-strength aluminium alloys are heat-treated before use in primary airframe structure?

  1. To increase electrical conductivity for bonding
  2. To increase yield strength through precipitation hardening Correct answer.
  3. To reduce density to lower the empty weight
  4. To improve resistance to fuel and hydraulic fluid

Explanation

Solution treatment and artificial ageing precipitate fine particles that raise the yield strength of alloys such as 2024 and 7075, which is essential for weight-efficient primary structure. Heat treatment does not significantly change density or fluid resistance. Electrical conductivity is not the design driver.

Question 9Aeroplane airframe structures and systems

A sheet metal repair to a pressurised fuselage skin must maintain the original fatigue life. Which approach best achieves this?

  1. Attach the patch with adhesive only, without fasteners
  2. Use a doubler with correctly sized and spaced fasteners, properly sealed and stress-relieved at the edges Correct answer.
  3. Butt-join the patch with a single row of blind rivets
  4. Use a single row of closely spaced rivets along the patch boundary

Explanation

A properly designed doubler restores load path and stiffness, and correct fastener size, spacing, and edge treatment reduce stress concentrations that would shorten fatigue life. Single-row or blind-rivet joints concentrate load and are poor fatigue details, and adhesive-only patches are not approved for primary pressurised structure.

Question 10Aeroplane airframe structures and systems

What is the function of a wing rib in a metal wing structure?

  1. It reacts the engine thrust loads at the nacelle
  2. It maintains the aerofoil contour and transfers loads between skin, spars, and stringers Correct answer.
  3. It provides the main fuel tank boundary along the span
  4. It carries the wing bending moment to the fuselage attachment

Explanation

Ribs preserve the wing section shape and distribute concentrated loads such as landing gear, control surface, or fuel tank reactions into the skin and spars. Bending is carried by the spar caps, and thrust is reacted at the engine mount structure.

Question 11Aeroplane airframe structures and systems

A control cable in a primary flight control system shows broken wire strands near a pulley. What is the correct action?

  1. Shorten the cable and re-rig to remove the damaged section
  2. Assess against the approved cable defect limits and replace the cable if limits are exceeded Correct answer.
  3. Lubricate the cable and monitor at the next scheduled check
  4. Apply a swaged sleeve over the broken strands and return to service

Explanation

Cable condition is judged against published limits for broken strands, corrosion, and wear, and cables exceeding those limits must be replaced. Sleeving, shortening, or deferring repair of a primary control cable is not an approved practice and could cause loss of control.

Question 12Aeroplane airframe structures and systems

In a hydraulically powered flight control system, what is the purpose of a hydraulic fuse?

  1. It filters contamination from the hydraulic fluid
  2. It limits the maximum system pressure by bypassing fluid to return
  3. It absorbs pressure surges in the return line
  4. It shuts off flow to a downstream line if a leak causes excessive flow Correct answer.

Explanation

A hydraulic fuse detects abnormally high flow, as would occur with a downstream line rupture, and closes to conserve fluid and maintain pressure for remaining services. Pressure limitation is the job of the pressure relief valve or pump compensator, and filtration is done by filters.

Question 13Aeroplane airframe structures and systems

An accumulator in an aircraft hydraulic system is pre-charged with nitrogen. What is its main function?

  1. To provide a backup source of hydraulic fluid volume
  2. To cool the hydraulic fluid during prolonged operation
  3. To separate water from the hydraulic fluid
  4. To store pressure energy for peak demands and damp pressure fluctuations Correct answer.

Explanation

The gas charge allows the accumulator to store energy, supply transient high flows, damp pressure pulses, and maintain pressure during brief pump drop-off. It does not cool fluid, remove water, or act as a fluid reservoir in the normal sense.

Question 14Aeroplane airframe structures and systems

A landing gear shock strut is serviced with nitrogen rather than air. Why is this preferred?

  1. Nitrogen is dry and inert, reducing internal corrosion and the risk of combustion Correct answer.
  2. Nitrogen provides higher pressure for the same volume
  3. Nitrogen has a lower density so the strut is lighter
  4. Nitrogen dissolves more readily in hydraulic fluid to damp oscillations

Explanation

Nitrogen is dry and chemically inert, which avoids moisture-driven corrosion inside the strut and eliminates the fire or explosion risk associated with an air-oil mixture under pressure. Density and solubility differences are not the design reasons, and pressure depends on charge amount and temperature.

Question 15Aeroplane airframe structures and systems

During a gear retraction check, the red landing gear unsafe warning remains illuminated after all three gears are up and locked. Which is the most likely cause?

  1. A faulty up-lock switch or its associated wiring circuit Correct answer.
  2. Low hydraulic fluid level in the reservoir
  3. A misrigged nose wheel steering linkage
  4. A worn tyre on the nose gear

Explanation

The unsafe warning depends on up-lock proximity switches signalling that each gear is locked; a faulty switch or wiring keeps the warning on despite correct mechanical position. Hydraulic level, tyre wear, and steering rigging do not affect the up-and-locked signal.

Question 16Aeroplane airframe structures and systems

What is the primary purpose of a spoiler on a wing?

  1. To reduce wing bending moment in turbulence
  2. To provide pitch trim about the lateral axis
  3. To increase lift at low speed during approach
  4. To spoil lift and increase drag, assisting roll control and descent Correct answer.

Explanation

Spoilers disrupt airflow over the wing, reducing lift and adding drag; they are used for roll assist, speedbrake function, and ground lift dumping. Lift augmentation is the role of flaps and slats, and pitch trim is provided by the elevator or trim system.

Question 17Aeroplane airframe structures and systems

A pitot-static system has a blocked static port while the pitot tube remains clear. What indication error is expected during a climb?

  1. Airspeed under-reads and the altimeter over-reads
  2. Airspeed under-reads and the altimeter under-reads Correct answer.
  3. Airspeed remains correct and only the vertical speed indicator is affected
  4. Airspeed over-reads and the altimeter over-reads

Explanation

A blocked static port traps the pressure from the blockage altitude. During a climb above that altitude, ambient static pressure decreases, so the trapped pressure is too high. Subtracting this higher pressure from pitot total pressure reduces the indicated airspeed. The altimeter remains at the blockage altitude and therefore also under-reads.

Question 18Aeroplane airframe structures and systems

In a pneumatic de-icing boot system, what happens when the timer cycles the boots?

  1. The boots inflate and deflate alternately to crack and shed accumulated ice Correct answer.
  2. The boots heat electrically to melt the ice layer
  3. The boots vibrate continuously to prevent ice formation
  4. The boots apply anti-icing fluid to the leading edge

Explanation

Pneumatic boots inflate periodically to break the bond between ice and the surface, and the ice is then removed by airflow. They are de-icing, not anti-icing, devices, and they do not use electric heating or fluid.

Question 19Aeroplane airframe structures and systems

A thermal anti-icing system uses engine bleed air to heat the wing leading edge. What is the main risk if the system is operated on the ground for an extended period?

  1. Overheating of the leading edge structure and damage to components Correct answer.
  2. Freezing of the bleed air valves
  3. Contamination of the bleed air with hydraulic fluid
  4. Excessive cooling of the bleed air supply

Explanation

On the ground with low airflow, bleed-air heating can raise leading-edge skin temperature beyond limits and damage structure, seals, or paint, so operation is restricted. The system heats rather than cools, and valve freezing or fluid contamination are not the primary ground-operation risk.

Question 20Aeroplane airframe structures and systems

What is the function of a fuel tank vent system in an aeroplane wing?

  1. To release fuel vapour to the engine for combustion
  2. To supply pressurised air for fuel transfer between tanks
  3. To allow fuel to drain overboard in an emergency
  4. To maintain near-ambient pressure in the tank as fuel is used or the aircraft climbs Correct answer.

Explanation

Vents keep tank pressure close to ambient, preventing structural loads from pressure differentials and allowing fuel to flow to the engines as the aircraft climbs. They are not an emergency dump, a transfer pressure source, or a vapour feed to the engine.

Question 21Aeroplane airframe structures and systems

During refuelling, a fuel quantity indication fails to increase although fuel is flowing. Which component should be checked first?

  1. The engine fuel control unit
  2. The fuel boost pump impeller
  3. The tank unit or probe and its associated wiring Correct answer.
  4. The fuel filter bypass indicator

Explanation

A quantity indication that does not respond points to the measuring element, such as a capacitance probe or float unit, or its wiring to the indicator. The fuel control unit, boost pump, and filter bypass do not generate the quantity signal.

Question 22Aeroplane airframe structures and systems

Why are fire detection loops in an engine compartment arranged in a dual-loop configuration?

  1. To increase the sensitivity of each individual sensor
  2. To reduce the total weight of the detection system
  3. To allow the loop to double as an overheat warning for the cabin
  4. To provide redundancy and allow fault isolation while maintaining detection capability Correct answer.

Explanation

Dual loops give redundancy so that a single loop fault does not disable fire detection, and the control unit can compare loops to isolate faults. Sensitivity, weight reduction, and cabin overheat warning are not the reasons for the dual arrangement.

Question 23Aeroplane airframe structures and systems

A Halon fire extinguisher bottle discharges into an engine nacelle. What is the primary mechanism by which it extinguishes the fire?

  1. It cools the compartment below the ignition temperature
  2. It displaces oxygen by forming a foam blanket
  3. It removes fuel from the fire zone
  4. It interrupts the chemical chain reaction of combustion Correct answer.

Explanation

Halon agents act mainly by chemically interrupting the combustion chain reaction, which is why they are effective at low concentration. Cooling and oxygen displacement are secondary or belong to other agents, and an extinguisher cannot remove the fuel source.

Question 24Aeroplane airframe structures and systems

What is the purpose of a cabin pressure outflow valve?

  1. It controls the temperature of the cabin supply air
  2. It relieves excessive positive pressure only during refuelling
  3. It admits fresh air into the cabin from the air-conditioning packs
  4. It modulates the rate at which cabin air escapes to control cabin altitude and rate of change Correct answer.

Explanation

The outflow valve regulates the escape of cabin air, thereby controlling cabin altitude and the rate of climb or descent of cabin pressure. Inflow is provided by the air-conditioning packs, temperature is controlled by pack and trim air valves, and pressure relief is handled by separate safety valves.

Question 25Aeroplane airframe structures and systems

An aircraft is fitted with a Mach trim system. What does this system do?

  1. It trims the rudder to counter asymmetric thrust
  2. It limits the maximum Mach number by retarding thrust
  3. It adjusts the stabiliser for centre of gravity changes due to fuel burn
  4. It applies elevator trim to counter the pitch-down tendency as Mach number increases Correct answer.

Explanation

Mach trim counters the Mach tuck or pitch-down tendency that develops as the aircraft approaches high Mach numbers, maintaining acceptable longitudinal characteristics. Overspeed protection and rudder or CG trim are separate functions.

Question 26Aeroplane airframe structures and systems

In a semi-monocoque fuselage, what is the primary role of the longitudinal stringers attached to the skin?

  1. They provide the continuous circumferential path that reacts cabin pressure hoop stress
  2. They seal the skin joints against pressurisation leakage
  3. They form the attachment points for the wing-to-fuselage joint fittings
  4. They carry and redistribute bending loads along the fuselage and stabilise the skin against buckling Correct answer.

Explanation

Stringers run lengthwise and, together with the skin, carry bending and shear loads while stiffening the skin panels so they resist buckling in compression. The frames and bulkheads provide the circumferential (hoop) load path and maintain the cross-sectional shape.

Question 27Aeroplane airframe structures and systems

An aeroplane has a free-castering nose wheel with a shimmy damper. What is the function of the shimmy damper?

  1. It limits nose wheel steering angle during low-speed taxiing
  2. It centres the nose wheel before landing touchdown
  3. It dampens rapid self-excited oscillation of the nose gear about its steering axis Correct answer.
  4. It locks the nose wheel in the fore-and-aft position during retraction

Explanation

Shimmy is a self-excited oscillation of the castoring gear about its vertical axis, and the damper adds hydraulic or friction resistance to suppress it. It does not provide centring, steering limits or retraction locking, which are separate functions.

Question 28Aeroplane airframe structures and systems

What is the main purpose of a vortex generator fitted on an aeroplane wing or control surface?

  1. To energise the boundary layer and delay flow separation Correct answer.
  2. To reduce induced drag by weakening the wingtip vortex
  3. To increase the wing area available for lift at high angles of attack
  4. To provide a controlled stall warning to the pilot

Explanation

Vortex generators are small vanes that mix higher-energy free-stream air into the boundary layer, keeping it attached at higher angles of attack and improving control effectiveness. They do not change wing area, and they increase rather than reduce drag.

Question 29Aeroplane airframe structures and systems

A composite sandwich panel in a floor structure has a disbond between the core and one facing. Which inspection method is best suited to detecting this internal defect?

  1. Dye penetrant inspection of the panel edges
  2. Magnetic particle inspection of the facing surface
  3. Tap testing supplemented by through-transmission ultrasonic inspection Correct answer.
  4. Eddy current inspection of the facing laminate

Explanation

Core-to-facing disbonds are internal and are best found by tap testing for audible change, confirmed by ultrasonic through-transmission which detects the loss of bond. Magnetic particle and dye penetrant only reveal surface-breaking defects, and eddy current is suited to conductive surface layers.

Question 30Aeroplane airframe structures and systems

A rigid hydraulic line in a pressurised aircraft is routed between two components that move relative to each other under load. How should the connection be made?

  1. A rigid tube with a single loop to absorb the movement
  2. A flexible hose assembly rated for the system pressure Correct answer.
  3. A continuous rigid tube with clamps at both ends
  4. A rigid tube joined at mid-span with a bulkhead union

Explanation

Relative movement between end fittings must be accommodated by a flexible hose, which is designed and qualified for the system pressure and fluid. A rigid tube with clamps or a single loop cannot absorb repeated relative displacement and will fatigue and crack.

Question 31Aeroplane airframe structures and systems

During a fuel system check, the fuel boost pump runs but no pressure rise is seen at the engine feed line and the low-pressure warning stays on. Which fault is most consistent with these indications?

  1. The pump impeller is worn or the pump inlet is obstructed Correct answer.
  2. The engine-driven pump has failed
  3. The fuel quantity indicating system is reading incorrectly
  4. The fuel tank vent is blocked

Explanation

A running pump that produces no pressure rise indicates the pump is not moving fuel, typically through impeller wear or a restricted inlet. A blocked vent would affect tank pressure and fuel flow but would not leave the boost pump producing zero output.

Question 32Aeroplane airframe structures and systems

An aircraft has a DC generator system with a reverse-current cut-out. What is the function of this cut-out?

  1. It limits the maximum current the generator can supply to the bus
  2. It disconnects the generator if the drive belt fails
  3. It regulates the generator field current to hold bus voltage constant
  4. It prevents the battery from discharging back through the generator when generator voltage falls below battery voltage Correct answer.

Explanation

The reverse-current cut-out opens the generator-to-bus contactor when current flows from the battery into the generator, which occurs when generator voltage falls below battery voltage. Current limiting and voltage regulation are separate functions of the control unit.

Question 33Aeroplane airframe structures and systems

A transport aeroplane has a mechanical backup path in its primary flight control system. During a full hydraulic failure, what determines the pilot's ability to control the aeroplane?

  1. The aerodynamic hinge moments transmitted through the mechanical linkage to the control surface Correct answer.
  2. The autopilot servos operating in manual mode
  3. The accumulator pressure retained in the hydraulic system
  4. The electrical trim actuators driving the surfaces

Explanation

With hydraulic power lost, the pilot must overcome the aerodynamic hinge moment of the surface through the mechanical linkage. This is why control forces and speed limitations are critical in a manual reversion case. Accumulators and powered actuators cannot sustain control without system pressure.

Question 34Aeroplane airframe structures and systems

A pressurised aeroplane is being inspected after a suspected overpressure event. Which structural area should receive particular attention for permanent deformation?

  1. The horizontal stabiliser leading edge
  2. The fuselage skin adjacent to the pressure bulkheads and door surrounds Correct answer.
  3. The main landing gear trunnion bearings
  4. The wing rear spar attachment fittings

Explanation

Overpressure loads act on the pressure vessel, so the skin, frames and joints around bulkheads and door cut-outs are the areas most likely to show permanent set or distress. Wing and gear fittings are loaded by flight and ground loads rather than cabin pressure.

Question 35Aeroplane systems - hydraulic, pneumatic, fuel and ice and rain protection

In a typical transport aeroplane hydraulic system, what is the primary function of the reservoir pressurisation?

  1. To provide a backup source of pressure if both engine-driven pumps fail
  2. To cool the fluid by allowing it to boil at altitude
  3. To increase system operating pressure above the relief valve setting
  4. To prevent pump cavitation and maintain a positive feed pressure at the pump inlet Correct answer.

Explanation

Reservoir pressurisation maintains a positive head at the pump inlet, which suppresses cavitation and ensures a continuous fluid supply at high altitude where ambient pressure is low. It does not raise system operating pressure, which is set by the pump and relief valve.

Question 36Aeroplane systems - hydraulic, pneumatic, fuel and ice and rain protection

A hydraulic system uses a piston-type accumulator. What does the nitrogen precharge provide when the system is at rest?

  1. It absorbs heat generated by the pump during operation
  2. It chemically reacts with the fluid to maintain viscosity
  3. It stores energy that can supply a limited volume of pressurised fluid during demand peaks Correct answer.
  4. It seals the piston against the cylinder bore

Explanation

The gas precharge is compressed as fluid enters the accumulator, storing energy that is released to supplement pump output during transient high demand and to hold pressure when pumps are off. The gas does not react with fluid, cool the system, or act as the piston seal.

Question 37Aeroplane systems - hydraulic, pneumatic, fuel and ice and rain protection

Why is Skydrol-type (phosphate ester) hydraulic fluid not compatible with natural rubber seals?

  1. It conducts electricity more readily than mineral fluid
  2. It attacks natural rubber, so seals must be made of butyl or ethylene-propylene compounds Correct answer.
  3. It has a lower flash point than mineral hydraulic fluid
  4. It freezes at a higher temperature than mineral fluid

Explanation

Phosphate ester fluids are chemically aggressive to many elastomers and require compatible seal materials such as butyl rubber or EPR. Using natural rubber would cause swelling and seal failure. Phosphate ester fluids are actually fire-resistant with high flash points.

Question 38Aeroplane systems - hydraulic, pneumatic, fuel and ice and rain protection

In an aircraft pneumatic system, what is the usual purpose of a pressure-reducing valve downstream of the engine bleed?

  1. To deliver a stable, lower pressure to user systems regardless of bleed pressure variations Correct answer.
  2. To cool the bleed air before it reaches the users
  3. To shut off bleed air completely if a duct leak occurs
  4. To prevent reverse flow through the bleed port

Explanation

A pressure-reducing valve regulates the bleed air down to a controlled lower pressure so downstream users such as air conditioning and pressurisation receive a stable supply. Shutoff, cooling, and reverse-flow prevention are handled by other components.

Question 39Aeroplane systems - hydraulic, pneumatic, fuel and ice and rain protection

What is the purpose of a fuel tank vent system in a pressurised aeroplane?

  1. To indicate fuel quantity to the flight deck
  2. To provide a path for fuel to transfer between tanks during refuelling
  3. To allow fuel vapour to be routed to the engines for combustion
  4. To keep the tank at approximately ambient pressure and prevent over or under pressure as fuel is used Correct answer.

Explanation

Vent systems maintain the tank near ambient pressure, preventing structural overpressure during refuelling and underpressure as fuel is consumed. They also allow air in and out as the tank breathes. They do not feed vapour to engines or measure quantity.

Question 40Aeroplane systems - hydraulic, pneumatic, fuel and ice and rain protection

Why is a fuel tank inerting system fitted to many modern transport aeroplanes?

  1. To increase the fuel's resistance to freezing at altitude
  2. To remove water from the fuel before it reaches the engine
  3. To improve the fuel's lubricity for the high-pressure pump
  4. To reduce the oxygen content in the ullage so that ignition of fuel vapour cannot occur Correct answer.

Explanation

Inerting replaces ullage oxygen with nitrogen-enriched air, lowering oxygen concentration below the level needed to support combustion of fuel vapour. It does not dry fuel, change freezing point, or affect lubricity.

Question 41Aeroplane systems - hydraulic, pneumatic, fuel and ice and rain protection

What is the purpose of a fluid anti-icing system on an aeroplane?

  1. To prevent ice formation on protected surfaces by supplying heated fluid before ice can form Correct answer.
  2. To provide a slippery coating so ice cannot adhere to any surface
  3. To melt ice only inside the engine intake
  4. To remove ice that has already accumulated on the protected surfaces

Explanation

Anti-icing prevents ice from forming, typically by distributing heated fluid over the protected area before icing conditions are encountered. De-icing removes ice already present.

Question 42Aeroplane systems - hydraulic, pneumatic, fuel and ice and rain protection

What is the function of a windshield rain repellent system?

  1. To heat the windshield above freezing point
  2. To provide a demisting airflow across the inner surface
  3. To apply a chemical that causes rain to bead and be blown clear of the windshield Correct answer.
  4. To increase the strength of the windshield against bird strike

Explanation

Rain repellent systems dispense a chemical that makes water bead so aerodynamic airflow clears the windshield, improving visibility. Heating, structural strength, and demisting are separate functions.

Question 43Aeroplane systems - hydraulic, pneumatic, fuel and ice and rain protection

An engine-driven hydraulic pump has failed but system pressure remains normal during cruise. What component is most likely supplying the pressure?

  1. The return filter bypass valve
  2. The relief valve opening to recirculate fluid
  3. The accumulator, supplemented by the remaining pump or a power transfer unit Correct answer.
  4. The reservoir pressurisation alone

Explanation

An accumulator stores pressurised fluid and can supply transient demand, while the other engine pump or a power transfer unit maintains system pressure. Reservoir pressurisation provides only head pressure and cannot sustain system pressure.

Question 44Aeroplane systems - hydraulic, pneumatic, fuel and ice and rain protection

During a hydraulic system leak check, fluid is found weeping from a flareless fitting on a return line. What is the most appropriate action?

  1. Apply thread sealant to the external threads and continue service
  2. Increase return line pressure to seat the ferrule more firmly
  3. Depressurise the system, inspect the fitting for correct assembly, and remake or replace it as required Correct answer.
  4. Tighten the fitting while the system is pressurised to stop the leak

Explanation

Leaking fittings must be investigated with the system depressurised so the joint can be inspected for correct assembly, damaged ferrules, or cracked flares. Tightening under pressure risks injury and does not correct a faulty joint.

Question 45Aeroplane systems - hydraulic, pneumatic, fuel and ice and rain protection

A hydraulic system relief valve is found to be set higher than the specified value. What is the consequence if left uncorrected?

  1. System components and seals may be subjected to pressures above their design limit Correct answer.
  2. The accumulator precharge will increase automatically
  3. The pump will deliver less flow than required during normal operation
  4. The reservoir will lose its pressurisation

Explanation

The relief valve protects the system from overpressure, so a high setting allows pressure to rise above the design limit and can damage seals, hoses, and components. It does not reduce flow, affect reservoir pressurisation, or change accumulator precharge.

Question 46Aeroplane systems - hydraulic, pneumatic, fuel and ice and rain protection

Why must hydraulic fluid samples be taken and analysed periodically on a transport aeroplane?

  1. To measure the exact system operating pressure
  2. To detect contamination and fluid degradation before they cause component wear or blockage Correct answer.
  3. To confirm the reservoir is correctly pressurised
  4. To verify the accumulator precharge value

Explanation

Fluid sampling detects particulate and water contamination and chemical degradation so maintenance can act before wear or blockages occur. Pressure, reservoir pressurisation, and precharge are checked by other means.

Question 47Aeroplane systems - hydraulic, pneumatic, fuel and ice and rain protection

On an aeroplane with a bleed air system, what is the purpose of the precooler?

  1. To reduce the temperature of engine bleed air before it enters the airframe ducts Correct answer.
  2. To reduce the pressure of bleed air to cabin pressure
  3. To remove oil and particulate contamination from bleed air
  4. To provide an alternate source of bleed air if an engine fails

Explanation

The precooler uses fan air to cool hot engine bleed air to a temperature the airframe ducts and components can withstand. Pressure regulation, contamination removal, and alternate supply are separate functions.

Question 48Aeroplane systems - hydraulic, pneumatic, fuel and ice and rain protection

A bleed air leak detection loop signals an overheat in a wing duct. What is the designed automatic response?

  1. The affected bleed valve closes to isolate the leak Correct answer.
  2. The cabin altitude rate is increased to vent the leak
  3. The precooler fan speed increases to cool the duct
  4. The opposite engine bleed pressure is raised to compensate

Explanation

Leak detection triggers closure of the associated bleed valve, isolating the leaking duct from the supply. Increasing fan speed, venting the cabin, or raising the other bleed pressure would not isolate the leak and could worsen the hazard.

Question 49Aeroplane systems - hydraulic, pneumatic, fuel and ice and rain protection

Which statement best describes the purpose of a fuel crossfeed system?

  1. It automatically refuels all tanks to a preset level
  2. It transfers fuel from the tanks to the APU only
  3. It allows either engine to draw fuel from any tank to balance fuel or manage an engine or tank fault Correct answer.
  4. It vents fuel vapour overboard during climb

Explanation

Crossfeed lets engines draw from tanks other than their own, allowing fuel balance correction and continued operation after a pump or tank fault. It is not limited to the APU, does not perform automatic refuelling, and is not a venting system.

Question 50Aeroplane systems - hydraulic, pneumatic, fuel and ice and rain protection

During cruise, a fuel temperature indication approaches the fuel's freezing point. What is a common crew action to raise fuel temperature?

  1. Increase cabin pressure to warm the tanks
  2. Open the crossfeed valves fully to circulate fuel faster
  3. Switch off the fuel boost pumps to reduce cooling
  4. Descend into warmer air or adjust tank fuel distribution to move cold fuel to a warmer tank Correct answer.

Explanation

Descending to warmer air raises the fuel temperature, and managing tank distribution can move cold fuel away from prolonged cold soak. Cabin pressure, pump operation, and crossfeed do not directly warm the fuel.