'Fail safe construction' is :

A type of construction in which the load is carried by other components if a part of the structure fails.

Which components do a semi-monocoque fuselage consists of?

A stressed skin structure in which the skin is supported by a lightweight framework, such as longerons, stringers and formers.

Monocoque fuselages derive their strength from:

The skin.

In the context of airframe load path philosophies a 'fail safe' component is:

a component incorporated in a large aircraft which is designed so that, following its failure, the remaining structure can withstand reasonable loads without failure until the damage is detected.

How can you tell when metallic bonding is incorrect?

Corrosion at skin joints

DURALUMIN alloys :

- have an aluminium-copper base.
- are difficult to weld.
- have a good thermal conductivity.

For FAIL-SAFE designed structural parts :

- The mounting principle is parallel mounting.
- The principle is the redundancy of composants
- The failure of a member causes the loads to be shared between the other system components.

What are the most frequent used materials in a monocoque or semi-monocoque structure?

Aluminium or magnesium alloy.

Monocoque fuselages derive their strength from:

The skin

A framework of truss type fuselage is used in:

light training aircraft mainly

Engine compartment decking and firewalls are manufactured from:

stainless steel or titanium sheet.

The purpose of stringers, used in fuselage construction, is to:

assist the skin to withstand longitudinal compressive loads.

The function of stringers in the construction of the fuselage is:

to provide support for the skin and to absorb some of the pressurization strain as tensile loading.

The fuselage of an aircraft consists, among others, of stringers whose purpose is to:

assist the skin in absorbing the longitudinal traction-compression stresses.v

Among the different types of aircraft structures, the shell structures efficiently transmit the:

1. normal bending stresses
3. torsion moment
4. shear stresses

The reason for the fact that an aeroplane designed for long distances cannot simply be used for short haul flights at higher frequencies is that

the lifetime of the fatigue sensitive parts has been based on a determined load Spectrum

With reference to stringers, they:

integrate the strains due to pressurisation to which the skin is subjected and convert them into a tensile stress.

MZFM is:

the total maximum permissible mass of the aircraft without usable fuel.

An electrically heated windscreen is manufactured from:

a glass and polycarbonate laminate.

Cockpit indications associated with a windscreen heating system usually comprise:

a green system "ON" information light and an amber system failure light.

The middle layer of a heated windscreen is made of:

soft polycarbonate.

When do you say that an aircraft has a cantilever wing?

When the wing is attached to the fuselage at or near one end only.

What mission does the strut have, often observed between the fuselage and the wing, on small high wing aircraft?

Supporting the wing while the aircraft is on ground and when airborne.

Wings without exterior support is called:


A wing structure consists primarily of:

a front and rear main spar with ribs and stringers

The torsion box of a modern aircraft wing structure consists of:

spars, skin, stringers and ribs

The wing of an aircraft in flight, powered by engines located under the wing, is subjected to a bending moment which causes its leading edge, from the wing root to the wing tip, to operate in:

compression, then in tension.

In flight the wing of an aircraft containing fuel is subjected to vertical loads that produce a bending moment which is:

highest at the wing root

The Maximum Zero Fuel Weight:


1 Is a limitation set by regulation.

1 Is a limitation set by regulation.
2 Is designed for a maximum load factor.
3 Is due to the maximum bending moment at wing root.

On a non-stressed skin type wing, the wing structure elements which take up the vertical bending moments Mx are:

the spars.

Which part of a wing, other than stressed skin construction, takes upward loads?


How can wing bending moments be reduced in flight?

By using aileron up float and using the fuel in the wings last.

The elevators of a conventional airplane are used to provide rotation about the

Lateral axis

What is the name of the control surface that rotates an aeroplane about its vertical axis?

The rudder

If the control stick of an aircraft is moved forward:

the elevator will move down.

Which controls act together by a V-tail aircraft?

The stick in one axis and the rudder pedals

What is the reason for putting the horizontal stabilizer on top of the fin?

To be out of the way of the wing down Wash

The empennage consists of the:

horizontal and vertical stabilizer

The advantage of mounting the tailplane on top of the vertical stabilizer is :

to withdraw it from the influence of wing turbulence

The two deformation modes that cause wing flutter are:

torsion and bending.

Why is a mach Pitch trim nessesary for high speeds?

Because the CPL changes its position with higher speeds

In a commercial transport aircraft the landing gear operating system is usually:

Hydraulically driven.

The part of the flight that will cause the highest loads on the torsion link in a bogie gear is

Taxiing with a small turning radius.

If an aircraft is equipped with a fixed gear, which of the mentioned factors will differ from a retractable landing gear?

Parasite drag

What are the two main types of landing gear used on modern aircraft?

Telescopic and sprung leg.

A torsion link assembly is installed on the landing gear to :

avoid rotation of the piston rod relative to the gear oleo strut.

Landing gear torque links are used to:

prevent rotation of the landing gear piston in the oleo strut.

Which is (are) the damping element(s) in a landing gear shock absorber used on larger aircraft ?

Nitrogen and a viscous liquid.

The purposes of the oil and the nitrogen in an oleo-pneumatic strut are :

the oil supplies the damping function and the nitrogen supplies the spring function

A scissor is a component found on landing gears. Its function is to :

prevent any rotation of the oleo strut in the undercarriage shock absorber.

An oleo-type landing gear shock absorber is often equipped with a torque link, why?

To allow the piston to move freely in and out the landing geai cylinder
To prevent the landing gear cylinder from rotating

Gear retraction systems are classified according to the power source used for retraction and extension. Which are the most frequently used on larger aircraft?


In a landing gear, movement is damped by:

nitrogen and liquid.

What is reducing the shocks on the landing gear in an oleo shock absorber?

Cushion of compressed air.

In a modern jet transport aircraft, how can the landing gear be extended if there is a complete hydraulic system failure.


A main landing gear is said to be "locked down" when:

the strut is locked by an overcentre mechanism.

If the normal method of lowering the hydraulic operated retractable landing gear fails, there has to be an alternate method, this usually works as?

A system integrated with the original that allows the gear, by mean of its own weight and aerodynamic resistance, to mechanically lock in place.

Overcentre mechanisms in landing gear systems are used to:

lock the landing gear in the up and/or down position.

The systems used for emergency extension of landing systems may comprise of:

2) compresses nitrogen
4) auxiliary hydraulic system
5) free fall

An undercarriage leg is locked when:

it is mechanically locked by on over-centre mechanism

In some aircraft, there is a protection device to avoid the landing gear being inadvertently retracted on the ground. It consists of :

A latch located in the landing gear lever.

To prevent the landing gear from collapsing when the aircraft is parked on the ground by, following device is used:

locking pins with flags

The illumination of the green lamp indicator corresponding to a landing gear means that the landing gear is :


Generally, on modern jet transport aeroplanes, if there is a complete hydraulic system failure, the landing gear can be extended:

by gravity extension.

The function of a scissor (torsion link) in a landing gear is to:

prevent any rotation of the oleo strut in the landing gear shock absorber.

The pilot may be prevented from retracting the landing gear whilst the aircraft is on the ground by:

the electrical control system being routed through the weight on wheels switch.

Shimmy occurs on the nosewheel landing gear during taxiing when:

the wheels tend to describe a sinusoidal motion on the ground

This effect is overcome by means of:

This effect of shimmy is overcome by means of:

4. an accumulator associated with the steering cylinder

an accumulator associated with the steering cylinder

Nose wheel shimmy" may be described as :

a possibly damaging vibration of the nose wheel when moving on the ground.

A hydraulically operated nose gear steering cylinder has at least two functions. The first is to allow the pilot to steer the aeroplane, and the second function is?

Shimmy dampener.

Control on the ground for small aeroplanes is provided by steering the nose wheel through connections to the rudder pedals, but large aeroplanes have normally:

Hydraulic power steering.

Shimmy is:

sinusoidal and possibly damaging movement of the nose wheel on the ground.

The cause of rather violent vibration of the nose wheel, described as shimmy, is often:

tyre imbalance.
looseness of the nose wheel support mechanism.

If the profile grooves or the tread of a new aircraft tyre are worn, the tyre can be:

Repaired several times.

The reason for fitting thermal plugs to aircraft wheels is that they :

release air from the tyre in case of overheating.

Thermal plugs are installed in:

wheel rims.

A tubeless tyre has :

2- no built-in-air tube.
4- a radial side casing.

When a landing gear wheel is hydroplaning, its friction factor is equal to:


A tubeless tyre is a tyre:

1. which requires solid or branches wheels
5. which does not burst in the event of a tyre ponctuer
6. which eliminates internal friction between the tube and the tyre

Tyre "creep" may be described as the :

circumferential movement of the tyre in relation to the wheel flange.

Compared to a tyre fitted with an inner tube, a tubeless tyre presents the following characteristics :

3 - lower risk of brushing
4 - better adjustment to wheels

On a modern aeroplane, to avoid the risk of tyre burst from overheating, due for example to prolonged braking during an aborted take-off, there is:

a hollow bolt screwed into the wheel which melts at a given temperature (thermal fuse) and deflates the tyre.

On an aircraft landing gear, an under-inflated tyre:

will wear at the shoulders

What are purpose and placing of a "fusible plug" on the tires?

It is placed in the wheel and reacts on temperature. At excessive temperatures it melts which allows the air to escape from the tire, leaving the tire unpressurized.

The "ply rating" of a tire is?

A parameter indicating the tire relative strength.

To avoid the risk of tyre burst from overheating there is:

a thermal plug that deflates the tyre at a specific temperature.

An under-inflated tyre on a dry runway:

increases wear on the shoulder.

The operating principle of an anti skid system is as follows : the brake pressure will be :

Decreased on the slower turning wheels.

The type of brake unit found on most transport aeroplanes is a:

Multiple disk brake.

In a hydraulic braking system, the accumulator is:

an accumulator designed to restore brake energy in the event of a hydraulic failure.

The modern anti-skid processes are based on the use of a computer whose input data is:

1. idle wheel speed (measured)
2. braked wheel speed (measured)
4. desired idle wheel train slipping rate

The function of a fusible plug is to

protect the tyre against explosion due to excessive temperature.

On large aeroplanes equipped with power brakes, the main source of power is derived from :

the aeroplane's hydraulic system.

The ABS (Auto Brake System) is being disconnected after landing ..

by pilot action

The disk brakes have more or less replaced the drum brakes. Why?

Owing to a loss of braking action due to heat generation problem.

On the brake assembly there is an anti-skid system. From which device does the anti-skid control box get the information to regulate the brake pressure?

From a wheel speed sensor.

On large modern transport aircraft, the brake assembly consist of?

Multiple disk brake type.

With the antiskid system unserviceable, how should brake application be made?

With an on and off braking action.

The main purpose of using anti-skid units in the wheel-brake system is to:

reduce tyre wear

The function of an accumulator in a hydraulic brake system is:

to supply a limited amount of brake energy in the event of failure of the hydraulic system normally supplying the brakes

In a hydraulic braking system, the accumulator is:

an accumulator designed to restore braking energy in the event of a hydraulic failure.

Auto-brakes are disengaged:

by the pilot.

In a HP brake hydraulic system:

a separate handbrake system is always fitted together with its own accumulator and its own system components.

In a hydraulic braking system, an accumulator is precharged to 1600 psi. An electrically driven hydraulic pump is started and provides a system pressure of 3000 psi. The hydraulic pressure gauge, which is connected to the gas section of the accumulator, r

3000 psi.

What brakes are used on modern transport aircraft?

Multi disc brakes.

An anti-skid system will:

reduce brake pressure to slower turning wheels.

The pressure for the braking system of a modern aircraft originates from:

the main hydraulic system.

With the anti-skid system unserviceable, how should brake application be made?

Which an on and off braking action.

The trim tab :

reduces hinge moment and control surface efficiency.

The purpose of a trim tab (device) is to:

reduce or to cancel control forces.

The advantages of fly-by-wire control are:

3. direct and indirect weight saving through simplification of systems
5. improvement of piloting quality throughout the flight envelope

An artificial feel unit is necessary in the pitch channel when:

the elevators are actuated by irreversible servo-control units.

An artificial feel unit system:

must be mounted in parallel on an irreversible servo-control unit.

In a steep turn to the left, when using spoilers ...

The right aileron will descend, the left one will ascend, the right spoiler will retract and the left one will extend.

The reason for the trim switch on a control column to consist of two separate switches is

To reduce the probability of a trim-runaway

On an aeroplane, spoilers are :

upper wing surface devices, their deflection is symmetrical or asymmetrical.

The control surface that rotates the aircraft about its longitudinal axis is/are the


The function of the rudder limiter on some aircraft is to?

Prevent excessive loads from acting on the rudder.

A servo tab moves?

Opposite of the control surface to which it is hinged.

The elevators of a conventional airliner are used to provide rotation about the:

Lateral axis

What is the name of the control surface that rotates an aeroplane about its longitudinal or roll axis

The ailerons

Longitudinal stability involves the motion of the aircraft about its:

Lateral axis

If the control stick of an aircraft is moved forward and to the right, the left aileron will move:

Down, and the elevator will move down.

With which system is differential control associated?

Aileron system.

If the control stick of an aircraft with properly rigged flight controls is moved rearward and to the left, the right aileron will move

down and the elevator will move up

The rudder limiters on several aircraft have a specific function, which is to:

Prevent excessive loads from acting on the rudder.

Some aircraft use a fly by wire system to move the primary flight controls, this system is based on;

Electrical signals from a computer sent to hydraulic actuators.

For a JAR 25 aeroplane, spoilers are:

upper wing surface devices, their deflection is symmetrical or asymmetrical.

If an artificial feel unit is fitted, it would be connected:

in parallel with the primary controls.

How do differential ailerons work?

Equalize the drag on up-going and down-going wings.

The range of control surface movements is limited by:

providing control stops.

Over-tensioned cables in a flight control system could result in:

excessive friction in the system.

A force gradient unit is used to:

add artifical feel into a hydraulically power flight control system.

What is the purpose of inboard ailerons?

To reduce wing twist at high speed.

What are flaperons?

Combined ailerons and flaps.

Where are spoilers fitted?

Symmetrically on the wing upper surface.

Why is artificial feel required and how is the degree of feel set?

Fitted to prevent overstressing of the aircraft and gives increased forces as the speed increases.

In a flight control system a device in which a small input operates a large output in a strictly proportionate manner is called:

a servomechanism.

Which is the correct statement regarding a large aircraft fitted with both inboard and outboard ailerons?

The outboard ailerons are typically used only when the flaps are extended.

With speed brakes deployed in flight and a pilot's input to turn left:

spoilers move up on the down-going wing and down on the up-going wing.

A cable operated control system has external locks:

When fitted to the control surface, they will prevent movement of the control column if the controls are not fitted with servo tabs.

A control surface has its limitations in movement by:

primary stops at the surface.

A primary stop is mounted on an elevator control system in order to:

restrict the range of movement of the elevator.

Some aircraft use a fly-by-wire system to move the primary flight controls. This system is based on:

electrical signals from a computer sent to hydraulic actuators.

Which of these signals are inputs, at least, in the stall warning computers?

Angle of attack and flaps and slats deflection.

On an aircraft, the Krueger flap is a:

leading edge flap close to the wing root

One type of flap used on aircraft moves down and increases the wing area by moving aft when lowered. This flap is known as:

Fowler flap.

Stall fences mounted on an aircraft wing are used:

To prevent the tendency of the outer portion of the wing to stall first.

Flaps which not only move down, but also increase the wing area by extending backwards on tracking are called:

Fowler flap.

A Krueger flap is:

A leading edge flap type which is formed by extending an area of the ring downwards and forward at the leading edge.

Trailing edge flaps:

increase lift at a lower AOA.

The reason for a double switch on the elevator trim is:

to reduce the probability of a trim runaway.

Why are flaps and slats fitted to modern aircraft?

To reduce takeoff, approach and landing speeds to an acceptable level.

A "slot" on a wing is?

A leading edge device that causes some of the high energy air to flow over the upper surface of the wing.

Flaps which not only move down, but also increase the wing aera by extending backwards on tracking are called:

fowler flap.

Hydraulic fluids must have the following characteristics:

1. thermal stabilit�
2. low emulsifying characteristics
3. corrosion r�sistance
4. good resistance to combustion

In a hydraulic braking system, an accumulator is precharged to 1200 psi. An electrically driven hydraulic pump is started and provides a system pressure of 3000 psi. The hydraulic pressure gauge which is connected to the gas section of the accumulator, re

3000 psi

Hydraulic fluids :

Are irritating to eyes and skin.

Hydraulic fluids used in systems of modern airliners are:

Phosphate ester base fluids.

Hydraulic power is a function of :

System pressure and volume flow.

The type of hydraulic oil used in modern hydraulic systems is:

synthetic oil

Hydraulic fluids of synthetic origin are:


The type of hydraulic fluid which has the highest resistance against cavitation is :

Synthetic fluid.

A "hydraulic fuse" will:

Detect a sufficient pressure drop across itself, or a specified volume of fluid passing through itself, and then shut off the flow of fluid to prevent the system of emptying itself.

The main reasons for using pressurised hydraulic reservoirs on jet transport aircraft is/are:

To assure that an adequate supply of fluid free from foaming always is present at the pump inlet.

The oil reservoir in a hydraulic system has the purpose to serve as:

The compartment that stores the fluid.

A point at which the fluid can purge itself of air.

An expansion chamber to provide a space for the fluid when its volume increases due to a high temperature.

The reason for the pressure accumulator in the hydraulic system is:

The accumulator serves as an internal shock absorber for the hydraulic system.

A variable displacement type hydraulic pump:

Moves fluid quantity dependent on the system demand.

A complex hydraulic systems may pressurise the oil reservoir by means of bleed air from the engines, this is

To secure reliable oil supply to the hydraulic pumps.

State the advantages of the variable displacement hydraulic pump compared to the constant displacement pump.

The variable displacement pump adjusts the fluid pumped to the fluid required, and the pump thereby adjusts the pressure output itself, and it moves fluid only when necessary.

Pascal's law states that:

Pressure in an enclosed container is transmitted equally and undiminished to all parts of the container and acts at right angles to the enclosing walls.

A thermal relief valve is installed in order to?

Sense the ambient fluid temperature and when this temperature exceeds a pre-determined value, the valve depressurises the hydraulic system.

If piston A has an area of 2 cm� and piston B has an area of 10 cm�, when piston B moves down by 5 cm, how far will piston A have moved?

25 cm

In the diagram (not to scale), the balancing force required on the right hand side is:

100 N

The viscosity of a hydraulic fluid should be:

the lowest to minimize power consumption and resistance to flow.

Viscosity is:

the tendency of a liquid or gas to resist flow.

Where in a hydraulic system might overheat indicators be installed?

At the pumps.

What is the normal pressure in a main hydraulic system of a modern turbojet aircraft?

3000 psi

In hydraulic systems of modern transport category aircraft the fluids used are:

Synthetic oil.

In a modern hydraulic system, "hydraulic fuses" can be found. Their function is :

To prevent total system loss in case of a leaking hydraulic line.

In a hydraulic system, the reservoir is pressurized in order to:

prevent pump cavitation

The purpose of a shuttle valve is to:

Supply an operating unit with the most appropriate system pressure.

Shuttle valves will automatically:

Switch hydraulically operated units to the most appropriate pressure supply.

In addition to energy storage the accumulator of the hydraulic system is used :

for dampening pressure surges in the system.

The function of the selector valve is to:

communicate system pressure to either side of an actuator.

The component that transforms the hydraulic pressure into a linear motion is called ...

An actuator or jack.

The aircraft hydraulic system is designed to produce:

high pressure and large flow.

The hydraulic device similar to an electronic diode is a :

check valve.

Assuming an accumulator is pre-charged with air to 1000 psi and the hydraulic system is pressurised to 1500 psi, the accumulator gauge will read :

1500 psi.

Internal leakage in a hydraulic system will cause :

an increased fluid temperature.

Discounting the possibility of leak, the level in a hydraulic reservoir will :

fluctuate with jack displacement and accumulator pressure.

An accumulator in a hydraulic system will :

store fluid under pressure.

Assuming a hydraulic accumulator is pre-charged with air to 1000 psi. If the hydraulic system is then pressurised to its operating pressure of 3000 psi, the indicated pressure on the air side of the accumulator should be :

3000 psi.

The schematic diagram illustrates a jack and selector valve in a typical hydraulic system. Assuming hydraulic pressure throughout :

a condition of hydraulic lock exists and no movement of the jack will take place.

In hydraulic system, a shuttle valve :

allows two possible sources of pressure to operate one unit.

To allow for failure of the normal method of system pressure limiting control, a hydraulic system often incorpor�tes

a high pressure relief valve.

The Ram Air Turbine (RAT) provides emergency hydraulic power for :

flight controls in the event of loss of engine driven hydraulic power.

The hydraulic oil, entering the hydraulic pump, is slightly pressurised to :

prevent cavitation in the pump

The low pressure switch of a hydraulic circuit sets off an alarm if :

the pump output pressure is insufficient.

For an aeroplane hydraulic supply circuit, the correct statement is :

the security components comprise the filters, the pressure relief valves, the by-passes, and the fire shut-off valve.

The tanks of a hydraulic system are pressurized:

by bleed air coming from the turbine-engine.

Relationships between the force, pressure and area

force = pressure x area

The following is normally true regarding hydraulic hand pumps. They are:

connected to the bottom of the r�servoir

What is the purpose of a "relief valve" in the hydraulic system?

Make sure that the pressure does not exceed the max. permitted pressure in the system.

In a hydraulic system the master cylinders inner diameter is 10 mm2, and the actuator cylinders inner diameter is 100 mm2. If you press the master-cylinder 2 cm by using a 100 N force, the actuator cylinder will move:

2 mm and produce a force of 1000 N

The indication of an internal leak in a hydraulic system will be:

a rise in fluid temp�rature

The purpose of pressurising some hydraulic reservoirs is to:

provide a positive feed to the main pump

A modern aeroplane is equipped with warning lights in the cockpit to monitor the hydraulic system. What does the illumination of the hydraulic oil temperature light indicate?

Overheated hydraulic fluid in one of the pump return lines.

Where in a hydraulic system might overheat sensors be installed?

At the pumps.

The total number of hydraulic pumps in this hydraulic system (excluding the PTU pump) is:


Synthetic hydraulic fluids:

are irritating to eyes and skin.

The transport aircraft hydraulic system is designed to produce:

high pressure and large flow.

An automatic cut-out valve is used in a:

fixed volume pressure control system.

A pressure regulator is used in a hydraulic system:

in conjunction with a constant delivery type pump.

A single action actuator:

is powered in one direction only by hydraulic power, the return movement being under spring force.

Axial piston pumps are often used in hydraulic systems due to:

their ability to produce high pressure when required but can be off loaded to reduce power consumption.

Filters in hydraulic systems often incorporate pop out indicators to:

warn of an impending by-pass situation.

Filtration in a hydraulic system is usually ensured by:

filters in both the pressure and return lines.

In a hydraulic system, overheat detectors are mostly installed:

at the pumps.

One of the functions of an accumulator in a hydraulic system is:

to damp pressure surges in the system.

Should a hydraulic pump seize during operation:

the quill drive will shear to offload and protect the gearbox.

The purpose of an accumulator in a hydraulic system is:

to damp the fluid pressure variations

When powering up a hydraulic system, the level in the reservoir will:

decrease slightly.

The purpose of a hydraulic fuse is to:

prevent leakage if the hydraulic line breaks.

A shuttle valve will:

automatically switch to a more appropriate source of hydraulic supply.

In the event of the normal hydraulic pressure regulation system failure, the following component is fitted in a typical hydraulic system:

a pressure relief valve.

Hydraulic pressure typically used in the system of large transport aircraft is:

3000 - 4000 psi

The temperature of hydraulic fluid is measured:

in the reservoir.

A linear actuator has a damaged seal, resulting in an internal leak. In addition to a loss of actuator efficiency, this will result in:

an increase in fluid temperature.

If a hydraulic pump switch light "LOW" caption illuminates, the cause is assumed to be:

pump output pressure low.

If the cabin altitude rises (aircraft in level flight), the differential pressure:


During a normal pressurised climb after take-off:

cabin pressure decreases more slowly than atmospheric pressure

The purpose of cabin air flow control valves in a pressurisation system is to :

Maintain a constant and sufficient mass air flow to ventilate the cabin and minimise cabin pressure surges.

Assuming cabin differential pressure has attained the required value in normal flight conditions, if flight altitude is maintained:

a constant mass air flow is permitted through the cabin.

Cabin pressure is controlled by :

delivering a substantially constant flow of air into the cabin and controlling the outflow.

During level flight at a constant cabin pressure altitude (which could be decreased, even at this flight level), the cabin discharge valves are:

Partially open.

The cabin pressure is regulated by the:

Outflow valve.

The pressurisation of the cabin is controlled by :

The cabin outflow valve.

Cabin differential pressure means the pressure difference between:

cabin pressure and ambient air pressure.

Cabin altitude means the:

cabin pressure expressed as altitude.

If the maximum operating altitude of an airplane is limited by the pressurized cabin, this limitation is due to the maximum:

Positive cabin differential pressure at maximum cabin altitude.

The cabin rate of descent is:

a cabin pressure increase.

The term "cabin pressure" applies when an aeroplane:

has the means to maintain the cabin pressure at a higher level than the ambient pressure.

When air is compressed for pressurization purposes, the percentage oxygen content is:


If the pressure in the cabin tends to become lower than the outside ambient air pressure the :

negative pressure relief valve will open.

A cabin pressure controller maintains a pre-set cabin altitude by regulating the :

position of the outflow valve(s).

In a manually operated system, the cabin altitude rate of change is normally controlled by :

a rate of change selector.

The term "pressure cabin" applies when an aeroplane :

has the means to maintain cabin pressure higher than ambient pressure.

Under normal flight conditions, cabin pressure is controlled by :

regulating the discharge of air through the outflow valve(s).

Assuming cabin differential pressure has attained the required value in normal flight conditions, if flight altitude is maintained :

a constant mass air flow is permitted through the cabin.

Assuming cabin pressure decreases, the cabin rate of climb indicator should indicate :

a rate of climb.

Assume that during cruise flight with air conditioning packs ON, the outflow valve(s) would close. The result would be that:

the pressure differential would go to the maximum value

When pressurising the cabin of an aircraft, the cabin pressure controller operates the

outflow valve

An aircraft climbs and in order to maintain the same cabin pressure during climb, what mode of operation will the pressurisation system make use of?


A combustion heater system is normally supplied from by:

fuel from the aircraft fuel system.

What happens to the indications on a cabin VSI, cabin altimeter and differential pressure gauge if an aircraft suffers a decompression?

VSI up, altimeter up, differential pressure gauge down.

Automatic temperature control of the system as shown would be accomplished by:

the temperature selector in conjunction with cabin sensors and the temperature regulator, modulating the mix valve.

A turbo compressor air conditioning system (bootstrap system) will:

cause a pressure drop as well as an associated temperature drop in the charge air.

If the automatic control of an air conditioning system fails:

the pilot can revert to manual control and set the control valve to the required setting.

If the pressure controller malfunctions and the outflow valve malfunctions (remains fully open), what happens to:

cabin ROC increase
cabin altitude increase
diff�rentiel pressure decrease

If the cabin pressure tends to decrease below ambient:

the inward relief valve will open.

If the discharge valves fail in the closed position in flight, the effect will be:

the cabin pressure will rise to maximum differential pressure.

If during pressurized flight the outflow valve closes fully due to a fault in the pressure controller, the:

safety valve opens when the differential pressure reaches structural maximum differential.

The pneumatic ice protection system is mainly used for:


With regard to the pneumatic mechanical devices which afford protection against the formation of ice, the only correct statement is:

The pneumatic mechanical device can only be used as a de-icing device.

A pneumatic de-ice system should be operated ..

When there is approximately 1,5 cm of ice on leading edges.

Concerning the sequential pneumatic impulses used in certain leading edge de-icing devices, one can affirm that :

2 - They are triggered from the flight deck after icing has become visible.
3 - A cycle lasts more than ten seconds.

Regarding carburettor ice, state the environmental caution areas for the formation of this type of ice.

Temperature between - 5� C and + 18� C, visible moisture or relative humidity greater than 60 %.

The tubes in the de-ice boots are usually inflated alternately. Why?

Because alternate inflation of de-ice boot tubes keeps disturbance of the airflow to minimum.

How much ice should be allowed to accumulate on the leading edge of the wing before the "de-ice boot" system is activated?

1/4" - 1/2

The power source for hot air in de-ice / anti ice systems on jet A/C is :

Bleed air from the engines' compressor.

The boots of a pneumatic de-icing system are normally made of:

neoprene rubber

The accurate method of removing snow and ice that has accumulated on the aircraft during parking, is;

De-ice all surfaces with approved de-ice fluid

Why do the deice boots inflate alternately?

Alternate inflation of the tubes keeps the disturbance of the airflow to a minimum.

Which of the following is true with respect to heating of pitot and static sensors on IFR certified aircraft?

Pitot tubes are always provided with a heater, while static ports may also be heated.

The pneumatic system accumulator is useful :

to eliminate the fluid pressure variations.

In the pneumatic supply system of a modern transport aircraft, the air pressure is regulated. This pressure regulation occurs just before the manifold by the :

low pressure bleed air valve

On Jet aircraft the primary source of compressed air is:

Bleed air from engine driven compressor.

Cabin air for JAR 25 aeroplanes is usually taken from:

the high pressure compressor.

In the air cycle system the air is cooled down by expansion:

in the turbine.

The purpose of the cabin pressure controller, in the automatic mode, is to perform the following functions:

1. control of cabin altitude,
2. control of cabin altitude rate-of-change indicateur,
3. limitation of differential pressure

Main cabin temperature is:

controlled automatically, or by flight crew selection.

The purpose of a ditching control is to:

close the outflow valve(s).

Under normal conditions (JAR 25) the cabin pressure altitude is not allowed to exceed:

8000 ft

On a modern large pressurized transport aircraft, the maximum cabin differential pressure is approximately:

7 - 9 psi

On most modern airliners the cabin pressure is controlled by regulating the:

Airflow leaving the cabin.

The "cabin differential pressure" is:

cabin pressure minus ambient pressure.

The maximum differential pressure of a transonic transport category airplane is approximately:

9.0 psi

What is the purpose of the pack cooling fans in the air conditioning system?

Supplying the heat exchangers with cooling air during slow flights and ground operation.

The cabin air for modern airplanes is usually supplied by:

main engine compressors.

Cabin air for modern airplanes is usually taken from:

the low pressure compressor and from the high pressure compressor if necessary.

In an airplane air conditioning system the air cannot be treated for:


In a bootstrap system, the purpose of the heat exchangers is to:

cool bleed air and compressor air from the turbo refrigerator.

A warning device alerts the crew in case of an excessive cabin altitude. This warning must be triggered on reaching the following altitude:

10000 ft (approx. 3000 m)

Environmental system: in the air refrigeration unit, the water separation unit is placed:

after the cooling turbine.

The air-conditioning pack of a present-day aircraft consists of several components: these include two heat exchangers; the primary exchanger (P) and the secondary exchanger (S).
The functions of these heat exchangers are as follows:

P: precools the engine bleed air
S: reduces the temperature of the air from the primary exchanger or from the pack's compressor.

Conditioned" air is air that has:

been controled in respect of temperature and pressure.

The term "bootstrap", when used to identify a cabin air conditioning and pressurisation system, refers to the:

cold air unit (air cycle machine) arrangement.

In a bootstrap cooling system the supply air is first:


compressed, then goes through a heat exchanger, and across an expansion turbine.


In a cabin air conditioning system, equipped with a bootstrap, the mass air flow is routed via the:


secondary heat exchanger outlet to the turbine inlet of the cold air unit.


Engine bleed air used for air conditioning and pressurization in turbo-jet aeroplanes is usually taken from the:


compressor section.


The turbine in a cold air unit (air cycle machine):


drives the compressor in the unit, creating a temperature drop in the conditioning air.


In an air cycle type air conditioning system, reduction of air temperature and pressure is achieved by:


an expansion turbine.


In a "bootstrap" cooling system, the charge air is first compressed in the cold air unit to:


ensure an adequate pressure and temperature drop across the cooling turbine.


A turbo-fan cold air unit will:


cause a pressure drop as well as an associated temperature drop in the charge air.


The cabin heating supply in a heavy jet transport aircraft is obtained from :


hot air coming from the engine's compressors.


The pack cooling fan provides:


cooling air to the primary and secondary heat exchanger during slow flight and ground operation.


An aircraft with a pressurized cabin is settled at its cruise level.


During the flight, a malfunction of the pressure controller is detected by the crew and the cabin rate of climb indicator reads -200ft/min.


Given that :


DELTA P: Differential pressure


Zc: Cabin altitude


DELTA P will rise up to its maximum value, thus causing the safety relief valves to open.


An aircraft with a pressurized cabin flies at level 310.


Following a malfunction of the pressure controller, the outflow valve runs to the open position. Given :


VZc: Cabin rate of climb indication


Zc: Cabin pressure altitude


DELTA P: Differential pressure


This will result in a:


VZc increase


Zc increase


DELTA P decrease


The water separator of an air-conditioning unit is located at the cooling unit :


outlet and uses a centrifugal process.


Conditioned" air is air that has :


been controlled in respect of temperature and pressure.


The term "Bootstrap", when used to identify a cabin air conditioning and pressurisation system, refers to the :


cold air unit (air cycle machine) arrangement.


The function of an air cycle machine is to :


cool the bleed air.


A cabin pressurisation system is often installed on board turbine powered aircraft. If installed, it normally has


Two modes of operation.


The air-cycle cooling system produces cold air by:


Extracting heat energy across an expansion turbine.


A complete air-conditioning system includes at least:


air cycle machine


Why is the heater combustion chamber in an aircraft pressurisation system


completely separated from the ventilating system?


To prevent any exhaust gases from contaminating the cabin air.


Most of the cabin pressurisation systems have two modes of operation:


The isobaric mode and the constant pressure differential mode.


An aircraft with pressurised cabin has maximum cabin altitude of 8000 feet, which equals 10.9 PSI. Present flight altitude is 30.000 feet, which equals 4.36 PSI. Pressure at sea level equals 14.7 PSI. Calculate the difference pressure that influence the c


6.54 psid.


The main elements of a vapour cycle cooling system are:


compressor, condenser, dryer, expansion valve, evaporator.


On modern jet aeroplanes, where is the compressed air supply obtained from?


From the HP compressor lower stages (plus higher stages as required)


On turbojet aircraft the primary source of compressed air is:


bleed air from an engine driven compressor.


The maximum cabin differential pressure of a pressurized aeroplane operating at FL 370 is approximately:


9,0 psi


Cabin air for a large aeroplane during flight:


is temperature controlled.


In a turbo compressor air conditioning system (bootstrap system), the main water separation unit is located:


after the cooling turbine.


In a turbo compressor air conditioning system (bootstrap system), the purpose of the heat exchangers is to:


cool the bleed air in front and behind the compressor of the air cycle machine.


In an air cycle machine:


the turbine drives the compressor of the machine which causes a higher temperature, thus increasing the secondary heat exchanger efficiency.


Temperature regulation of an air conditioning system:


is automatically controlled by sensing the output temperature from the control valve in relation to the temperature set on the pilot's control panel.


The purpose of an air conditioning pack inlet flow valve (pack valve) is to:


maintain a constant and sufficient air mass flow to ventilate the cabin.


In a bootstrap air conditioning system what is the correct sequence describing the routing of the air?


Goes through the compressor, secondary heat exchanger, turbine.


The turbine in the air conditioning machine:


drives the compressor and creates a temperature drop in the conditioned air.


The de-humidifier (water separator) is fitted:


after the cooling system, and operates on a condensation principle.


Determine the maximum operating altitude for an aircraft with a maximum differential pressure of 7,04 psi and a cabin altitude of 4.000 ft from the figure below:


24.000 ft


Why, in the bootstrap system, is the air compressed before it enters the heat exchanger?


To ensure maximum pressure and temperature drop across the turbine.


An aircraft with a pressurised cabin has a maximum cabin altitude of 8.000 feet, which equals 10,9 psi. Present flight altitude is 30.000 feet, which equals 4,36 psi. Pressure at sea level equals 14,7 psi.


Calculate the pressure differential:


6,54 psi





21.1.9 Air Driven Systems (Turboprop and Jet aircraft)

... Anti-icing and De-icing Systems (15)

In flight, the most commonly used anti-icing method for the wings of modern commercial aircraft fitted with turbo-jet units is:


Thermal (use of hot air).


Concerning electrically powered ice protection devices, the only true statement is:


on modern aeroplanes, electrically powered thermal devices are used to prevent icing on small surfaces (pitot-static, windshield...).


The elements specifically protected against icing on transport aircraft are:


1) engine air intake and pod.


2) front glass shield.


3) radome.


4) pitot tubes and waste water exhaust masts.


5) leading edge of wing.


6) cabin windows.


7) trailing edge of wings.


8) electronic equipment compartment.


The combination regrouping all the correct statements is :


1, 2, 4, 5


The ice protection system currently used for the most modern jet aeroplanes is the


Hot air system.


During flight, the wing anti-ice system has to protect


leading edges, slats and the leading edge flaps.


In jet aeroplanes the 'thermal anti-ice system' is primary supplied by


bleed air from the engines.


The anti-ice or de-icing system which is mostly used for the wings of modern turboprop aeroplanes is :


Pneumatic boots.


The ice protection for propellers of modern turboprop aeroplanes works




The advantages of thermal anti-icing are :


1. Simple and reliable system


2. Profiles maintained


3. Greater efficiency than that of an electrical resistor


4. Direct use of the hot air from the jet engine without substantial reduction in engine thrust


The combination of correct statements is:




The engine anti ice system should be used based upon the following information:


Reported temperature when on ground, and ram air temperature when airborne.


Essential information whether to use the engine anti-ice system or not, is?


Reported temperature when on ground, and ram air temperature when airborne.


Generally, for large aeroplanes, electrical heating for ice protection is used on:


pitot tubes.


In a bleed air anti-icing system, the areas that are typically heated are:


the leading edges of the wings and empennage.


The power source for hot air in the de-icing/anti-icing system on jet aeroplanes is:


bleed air from the engine's compressor.


The principle upon which the vibrating probe (Rosemount) ice detector is based, is:







21.1.10 Non-pneumatic operated de-ice systems

... Schematic construction, functioning and oper. (7)

On modern transport aircraft, cockpit windows are protected against icing by :


Electric heating.


Usually, electric heating for ice protection is used on:


Pitot tubes.


The heating facility for the windshield of an aircraft is:


Used on a continual basis as it reduces the thermal gradients which adversely affect the useful life of the components.


The correct statement about rain protection for cockpit windshields is that :


rain repellent should never be sprayed onto the windshield unless the rainfall is very heavy


In the case of a thermal de-icing system overtemperature, this indicated by:


warning lights


The probe heater op�r�tes


automatically, when the probe detects ice.


In order to prevent/eliminate ice buildups on a pitot tube on light aircraft, the pilot can use


a heating system consisting of an electric resistor inside the tube itself.





21.1.11 Fuel system

... Fuel tanks (17)

The purpose of the baffles in an aircraft's integral fuel tank is to:


Prevent the fuel from flowing to the wing tips during abnormal manoeuvre (side slipping...).


On a transport type aircraft the fuel tank system is vented through:


Ram air scoops on the underside of the wing.


The types of fuel tanks used on most modern transport aircraft are:


Integral tanks.


The purpose of baffle check valves fitted in aircraft fuel tanks is to :


prevent fuel movement to the wing tip.


The pressurization of tanks is maintained by the fuel:


vent system.


The automatic fuelling shut off valve:


stops fuelling as soon as a certain fuel level is reached inside the tank.


The refueling in a transport jet aircraft is made ...


Through a unique point (an underwing refueling center).


Fire precautions to be observed before refuelling are :


All bonding and earthing connections between ground equipment and the aircraft should be made before filler caps are removed.


The function of a feed box in the fuel tank is to


increase the fuel level at the boost pump location


Special fuel consumption schedules during flight are designed due


to minimise the wing G-loads and preserve main tank fuel for landing.


When checking the fuel for possible water content, the presence of water will be indicated by:


The water will be found at the bottom of the strainer, because it is heavier than the fuel.


The fuel tanks in small aircraft are mainly located:


In the wings


Modern jet aircraft: What are the fuel tank types and their location?


Integral tanks in the wings and in the fuselage.


Baffles can be mounted inside the tanks to


prevent fuel sloshes.


In flight, with centre tank empty and APU operating, a fuel unbalance is detected (quantity in tank 1 is less than quantity in tank 2). Re-balancing of the two tanks is:


possible with "crossfeed" open and tank 1 pumps "off" and tank 2 pumps "on".


How much vent space is required in fuel tanks by EASA CS-23 and CS-25 rules?


2 % of the total tank space in each individual tank.


What is the purpose of a surge box inside a fuel tank?


Prevent sloshing of fuel away from pump inlet during abnormal manoeuvres.





21.1.11 Fuel system

... Fuel feed (19)

During fueling the automatic fueling shut off valves will switch off the fuel supply system when:


the fuel has reached a predetermined volume or mass.


On most transport aircraft, the low pressure pumps of the fuel system are:


centrifugal pumps, driven by an electric motor.


The fuel supply system on a jet engine includes a fuel heating device, upstream of the main fuel filter so as to:


prevent, at low fuel temperature, the risk of ice formation from water contained in the fuel.


On most transport jet aircraft, the low pressure pumps of the fuel system are supplied with electric power of the following type:


115 V AC


The fuel crossfeed system:


allows feeding of any engine from any fuel tank.


On most transport aircraft, the low pressure pumps of the fuel system are:


Centrifugal pumps.


On a jet aircraft fuel heaters are :


Located on the engines.


The crossfeed fuel system is used to :


feed every engine from any fuel tank.


The fuel system boost pumps are submerged in the fuel ..


To prime the pumps.


The vapor lock is :


A stoppage in a fuel feeding line caused by a fuel vapor bubble.


The fuel system boost pumps are used to :


avoid the bubbles accumulation and feed the lines with fuel for directing it to the engine at a positive pressure.


The crossfeed fuel system enables:


the supply of any jet engine from any fuel tank.


Fuel pumps submerged in the fuel tanks of a multi-engine aircraft are:


centrifugal low pressure type pumps.


Given the following information, which statement is the most correct?


While in cruise flight, a circuit breaker corresponding to one of the fuel boost pumps, trips. The circuit breaker can not be reset:


The pump remains inoperative.


When baffles are fitted to aircraft fuel tanks, the purpose is to:


prevent surge of fuel within the tank during flight


The most appropriate statement concerning multi engine jet aeroplane fuel systems, is:


The fuel system may have provisions for heating the fuel before it enters the fuel filter.


The purpose of a refuelling volumetric top-off unit (VTO) is:


to close the fuelling valve when the tank is full.


On what principle does the fuel contents gauging system work on a modern large aircraft?


Changes in dielectric causes changes in capacitance


The auxiliary fuel pumps are:


electrically driven and are connected in series with the main fuel booster pump.





21.1.11 Fuel system

... Fuel dumping system (2)

The maximum quantity of fuel that can be dumped with the jettisoning system is:


All up to a defined reserve quantity.


Fuel dump systems are required:


on all transport category aircraft where the Maximum Take-Off Weight (MTWO) is significant higher than the Maximum Landing Weight (MLW).





21.1.11 Fuel system

... Fuel system monitoring (7)

The diagram shown represents a jet fuel system. The fuel-flow measurement is carried out :


after high pressure valve (item 4).


The capacitance type fuel gauging system indicates the fuel quantity by measuring the:


dielectric change between fuel and air.


In a compensated capacitance type quantity indicating system, the contents gauge of a half-full fuel tank indicates a fuel mass of 8000 lb. If a temperature rise increased the volume of fuel by 5 %, the indicated fuel weight would :


remain the same.


On A/C with a fuel pressure gauge, where is the pressure normally measured?


(Aircraft with fuel injection)


Inlet of the fuel injection metering unit.


Why is the capacitance-type fuel quantity gauge system the system that is most


often used on large turbine aircraft?


Because it measures the mass of fuel rather than the volume of fuel in the tank.


An electrically activated and operated fuel valve is called a(n):


Solenoid valve.


The indications of a failure of the capacitive fuel indication system will be:


a full deflection of the gauge to empty