Final Test 2

Question 1

If carburettor ice has formed on an engine fitted with a CSU, the application of carburettor heat will cause
[a] a drop in manifold pressure and a drop in RPM
[b] an initial drop, followed by an increase in manifold pressure at constant RPM
[c] a rise in both manifold pressure and RPM
[c] a rise in manifold pressure and a drop in RPM

Answer 1

B
Because ice takes time to melt, for a few seconds there is ice and hot air in the induction
system . As the ice is melted the manifold pressure will slowly increase, however it will
not return to normal even when all the ice has melted, since the heated air is still present.
When the carby heat is finally returned to “off’, the indications will return to normal.

Question 2

During a long descent cylinder head temperature becomes too low. This can be rectified by
[a] opening the cowl flaps
[b] adding power and increasing the rate of descent
[c] adding power and decreasing the rate of descent
[d] reducing the indicated airspeed

Answer 2

C
Adding power produces more engine heat, decreasing the rate of descent by maintaining
or reducing air speed reduces the heat lost by air cooling.

Question 3

During a long climb, the cylinder head temperature becomes too high. This can be rectified by
[a] closing the cowl flaps
[b] reducing the climbing indicated air speed
[c] leaning the mixture to best power
[d] richening the mixture to full rich and increasing the climbing indicated air speed

Answer 3

D
With mixture full rich, extra fuel is introduced into the cylinders to help cool the engine.
This has the most immediate effect since it goes straight to the heart of the problem-the
combustion chamber. Since the engine is aircooled, an increase in IAS helps carry more
heat away.

Question 4

During take off from a strip where the density altitude is extremely high, the best take off performance would be
achieved by setting the mixture control for
[a] fully rich
[b] peak EGT
[c] smooth running
[d] best economy

Answer 4

C
When mixture is set to full rich for take off, it is far richer than required for power
production. The extra fuel is used to cool the engine at take off power. If the ambient air
density is very low, the mixture can become so rich that rough running results. This effect
would not be noticed except in extreme conditions such as high mountain strips in the
summer in the tropics. Ag Pilots often use this technique.

Question 5

The best TAS at a given height and manifold pressure would be achieved with the mixture control set for
[a] full rich [b] best economy
[c] best power [d] peak EGT

Answer 5

C
The higher the power the higher the TAS.

Question 6

If maximum power is applied for take off while the oil temperature is too low
[a] the engine components could suffer stresses due to uneven heating
[b] take off manifold pressure could be lower than normal
[c] cylinder head temperature would become too high during take off
[d] take off power would be severely reduced

Answer 6

A
Because an aircraft engine is aircooled, it tends to change its temperature in response to
power changes much more quickly than a liquid cooled engine. When take-off power is
applied to a cold engine, the different metal components heat and expand at different rates
giving rise to internal stresses. Also oil has a higher viscosity when cold so lubrication is
less effective.

Question 7

Vaporisation of fuel would be most likely to occur at high power settings
[a] with hot fuel and low atmospheric pressure
[b] with cold fuel and low atmospheric pressure
[c] with hot fuel and high atmospheric pressure
[d] with cold fuel and high atmospheric pressure

Answer 7

A
Heating a liquid increases its tendency to vapourise. Lower ambient atmospheric pressure
has the same effect, eg water boils at a lower temperature at high elevations.

Question 8

If the pilot suspects that fuel vaporisation is occurring during flight an appropriate response would be
[a] place the mixture control to fully rich [b] increase engine RPM
[c] change fuel tanks [d] operate the fuel boost pump

Answer 8

D
The boost pump assists the engine pump to move fuel through the lines, reducing the risk
of vaporisation.

Question 9

If the manifold pressure exceeds rated boost in a turbo charged engine
[a] fuel vaporisation would occur
[b] detonation and engine damage could result
[c] the engine would backfire and lose power
[d] cylinder head temperature will rise and power will be less than normal

Answer 9

B
Operation at excessive manifold pressure forces too much charge into the cylinders during
the induction stroke. When compression occurs, the heat generated raises the charge
temperature to the point where it detonates upon ignition.

Question 10

If failure of a CSU locks the propeller blades at one fixed position
[a] the pilot will not be able to change the propeller RPM
[b] the propeller RPM would change with engine power changes
[c] the engine will gradually lose RPM
[d] the propeller will over speed unless power is reduced

Answer 10

B
If the blades are locked in a fixed position, the propeller behaves as though it was a fixed
pitch propeller.

Question 11

The propeller pitch control is set to fully fine position during the engine run up. This is done to
[a] allow the propeller RPM to indicate engine power
[b] allow the pilot to check the maximum engine RPM available
[c] allow the engine to reach normal operating temperature
[d] prevent RPM from becoming too low at idle power settings

Answer 11

A
In the fully fine position, the propeller is behaving as though it was a fixed pitched
propeller. This is desirable during engine run-up as it allows the pilot to easily check engine
power through variations in engine RPM.

Question 12

If the oil pressure gauge begins to fluctuate during flight
[a] the oil temperature is too high [b] the oil pressure gauge is unserviceable
[c] the oil temperature is too low [d] the oil quantity is very low

Answer 12

D
There would have to be almost no oil left in the sump. As the pump outlet is occasionally
uncovered by the aircraft motion, the pressure drops and then builds up again.

Question 13

The cause of an abnormally high oil pressure indication could be
[a] oil quantity is too low [b] oil temperature is too low
[c] oil temperature is too high [d] the oil sump is overfilled

Answer 13

B
The viscosity of oil is higher when the oil is cold. Highly viscous oil offers high resistance
to the pump allowing high pressure to build up. Most pressure regulators allow a higher
oil pressure when the oil is cold.

Question 14

If the oil level in an operating engine is below the specified minimum
[a] the engine could overheat at high power settings
[b] oil temperature would be lower than normal
[c] engine power will be reduced
[d] there will be a large power loss due to increased engine friction

Answer 14

A
Apart from lubrication, oil plays an important part in cooling the engine. Too little oil
means the oil that is there becomes hotter.

Question 15

A centre zero ammeter shows a constant high charge rate when
[a] the alternator has failed [b] the alternator voltage is low
[c] all electrical loads are on [d] the battery is faulty

Answer 15

D
The current going to the battery during normal operation should be small. Just enough to
keep the battery “topped up”. This is about 1 or 2 amps. If the charge rate is constantly high
the battery is not accepting its charge.

Question 16

A left hand zero ammeter indicates zero when
[a] the alternator has failed [b] all electrical loads are off
[c] the battery is fully charged [d] the battery circuit is switched off

Answer 16

A
A left hand zero ammeter is placed in the alternator circuit. It indicates the alternator out
put. If it reads zero, the alternator has failed since there should always be some out-put
going to the battery even when all other loads are off.

Question 17

In an engine fitted with a constant speed unit the onset of fuel vapour locking would be indicated by
[a] falling manifold pressure [b] fluctuating RPM
[c] fluctuating fuel pressure [d] high fuel consumption

Answer 17

C
Vapour in the fuel lines is compressible. As it passes through the system the fuel pressure
drops to zero then returns to normal when liquid fuel flow resumes.

Question 18

The function of a forward facing fuel tank vent is to
[a] increase the fuel flow at high altitude [b] provide a positive pressure in the fuel tank
[c] allow fuel to escape if the tank is overfilled [d] reduce the air pressure in the fuel tank at high
speed

Answer 18

B
Forward-facing vents transmit total pressure to the fuel tank, producing a slight positive
pressure in the tank and enhancing fuel flow.

Question 19

The continuous use of a higher grade of fuel than recommended can cause
[a] overboosting of the engine [b] overheating and detonation
[c] an increased risk of vapour locking [d] corrosion of internal engine components

Answer 19

D
The lead deposits that are created when high octane fuel is used in an engine designed for
lower octane are corrosive.

Question 20

After hydraulic flaps are lowered in flight, they slowly return towards the up position of their own accord. A
possible reason for this problem is
[a] hydraulic oil is leaking from the system [b] the level of hydraulic oil is too low
[c] the hydraulic accumulator is leaking [d] the pressure regulator is set too low

Answer 20

A
If the flaps are returning to up position, the actuator must be pushing oil through the lines.
If the selector is in the “up” position, the oil must be going somewhere. It must be leaking
from the lines.

Question 21

If brake pedals feel normal when pressure is applied, but slowly leak down as pressure is maintained
[a] the hydraulic fluid level is low [b] there is air in the brake lines
[c] the brake pads are badly worn [d] there is a leak in the system

Answer 21

D
This is the classic symptom of fluid leaking from the lines.

Question 22

The manifold pressure gauge of a normally aspirated engine at full power at sea level would read
[a] more than the outside atmospheric pressure
[b] the same as the outside atmospheric pressure
[c] slightly less than the outside atmospheric pressure
[d] about 14.7 Hg”

Answer 22

C
A manifold pressure gauge is nothing more complicated than a barometer. It reads the atmospheric
pressure at the location of the sensor. When the aircraft is at rest with the engine inoperative, the -
manifold pressure gauge indicates the ambient atmospheric pressure. When the engine is at idle,
the closed throttle restricts airflow into the inlet manifold and manifold pressure is low. At full
throttle, the throttle valve is wide open, permitting maximum air flow into the inlet manifold so
manifold pressure rises. The air /fuel mixture then passes into the engine -through the inlet valve.
The pressure in the inlet manifold must always remain less than ambient pressure to permit a flow
from the outside atmosphere to the engine

Question 23

The most likely cause of a rapidly fluctuating cylinder head temperature gauge would be
[a] detonation [b] preignition
[c] high oil temperature [d] a faulty gauge

Answer 23

D
A large body of metal such as an engine cannot rapidly change its temperature from hot
to cold to hot. If the gauge is giving this indication, the gauge must be faulty.

Question 24

If the altimeter reading remains unchanged during a climb the most likely cause would be
[a] the pitot tube has become blocked [b] the static source has become blocked
[c] the vacuum pump is unserviceable [d] the case of the altimeter is leaking

Answer 24

B
The altimeter takes its pressure reading through the static port. If the static port is
blocked, there would be no change in static pressure in the instrument case, even though
the outside static pressure is actually changing.

Question 25

The indication shown on the face of a turn co-ordinator when turning while taxiing on level ground is
[a] a skid away from the direction of turn
[b] the ball remains in the centre while ever the wings are level
[c] a slip in the direction of turn
[d] a bank opposite the direction of turn

Answer 25

A
Any turn on level ground is unbalanced. Inertia throws the ball away from the centre of
the turn.

Question 26

During a turn, the reading of a magnetic compass in the southern hemisphere will
[a] lag behind the aircraft when turning onto north
[b] lead ahead of the aircraft when turning onto south
[c] lead ahead of the aircraft when turning onto north
[d] lag behind the aircraft when turning onto east or west

Answer 26

C
The combination of forces that act on a compass during a turn is such that the compass
reading runs ahead of the aircraft’s true heading when turning onto north in the southern
hemisphere. It lags behind the aircraft’s true heading when turning onto south.
The compass is “NIPPY ON NORTH - SLUGGISH ON SOUTH”
The pilot should “OVERSHOOT NORTH -UNDERSHOOT SOUTH”

Question 27

The engine operating conditions most likely to produce fouled spark plugs are
[a] high power and rich mixture [b] low power and rich mixture
[c] high power and lean mixture [d] low power and lean mixture

Answer 27

B
Low combustion temperatures allow oil to accumulate on the plug gaps without burning.

Question 28

In an engine fitted with a carburettor and a constant speed propeller, the absence of carburettor ice may be
confirmed by applying carburettor heat and noting an immediate
[a] decrease in manifold pressure with no further change
[b] increase in manifold pressure with a gradual change
[c] increase in manifold pressure with no further change
[d] decrease in manifold pressure with a gradual change

Answer 28

A
Because hot air is less dense than cool air, the application of carburettor heat causes a
drop in manifold pressure. This lower manifold pressure will remain as long as hot air
is selected.

Question 29

Operating an engine with the oil level below the specified minimum is likely to cause
[a] excessive oil consumption [b] spark plug fouling
[c] engine overheating [d] oil foaming

Answer 29

C
One important function of the oil is to carry heat away from the engine and dissipate it
through the oil cooler. A low oil quantity means less heat can be transported.

Question 30

During flight a centre zero ammeter shows an abnormally high positive reading for an extended period of time.
The correct interpretation of this is
[a] electrical instruments will overread
[b] the alternator has failed and the battery is powering the system
[c] the battery is being overcharged and may boil
[d] no particular meaning

Answer 30

C
If the battery will not accept the charge, a high current continues to flow through it
causing it to heat up. If allowed to continue, this can cause severe damage to the battery.

Question 31

The purpose of a turbocharger is to
[a] provide a constant rate of climb up to the critical altitude
[b] increase the mass of air flow into the engine
[c] increase the temperature and vaporisation of the fuel air mixture before induction
[d] reduce the possibility of detonation

Answer 31

B
The compressor increases manifold pressure and therefore mass air flow. This allows
more fuel to be burnt producing more power.

Question 32

What is the difference in appearance between aviation gasoline [avgas] and aviation turbine fuel [avtur]?
[a] avgas is blue or green while avtur is red
[b] avgas is red while turbine fuel is green
[c] avgas is clear while turbine fuel is blue or green
[d] avgas is blue or green while turbine fuel is clear

Answer 32

D
The colour in avgas is actually a dye put in to aid identification.

Question 33

Which instrument indication would suggest that the static vent has become blocked during a climb?
[a] the vertical speed indicator reads zero [b] all pressure instruments read zero
[c] the altimeter reads zero [d] the airspeed indicator reads zero

Answer 33

A
If the static vent is blocked, the VSI is isolated from the ambient air and can no longer
register any change in pressure.

Question 34

In a climb from level flight the altimeter reading remains unchanged. A likely cause would be a blockage in the
[a] pitot tube [b] vacuum pump
[c] static vent

Answer 34

C
If the static vent is blocked, the altimeter is isolated from the ambient air and can no
longer register any change in pressure

Question 35

What effect does the application of carburettor heat have on mixture and power?
[a] mixture becomes leaner and power is unaffected
[b] mixture becomes richer and power is reduced
[c] mixture becomes leaner and power is reduced
[d] mixture becomes richer and power is unaffected

Answer 35

B
Since the hot air is less dense than the cool air, the manifold pressure drops resulting in
a reduced power output. Since the carburettor continues to supply the same quantity of
fuel, the mixture becomes too rich.

Question 36

If an engine fitted with a fixed waste gate has the throttle fully opened at take-off -
[a] the rated boost would be exceeded.
[b] the engine would produce 100% of its rated power.
[b] the mixture would become too lean.
[d] the expected take-off performance would not be achieved.

Answer 36

A
A fixed waste gate relies on the pilot to monitor the boost being achieved. A take-off full throttle
would produce too much boost.