BGT Multi-Choice Flashcards
1
Q
Q. Which of the following additives are commonly used in Jet A1?
A. Anti-toxin.
B. Anti-serum.
C. Anti-microbiocodal.
D. Anti-inflammatory.
A
C. Anti-microbiocodal.
2
Q
Q. Over-temperature in a turbine engine is considered the most critical:
A. in the flame tube or combustion chamber.
B. in the area between the engine casing and nacelle structure.
C. at the first stage turbine assembly
D. at the propelling nozzle.
A
C. at the first stage turbine assembly
3
Q
Q. Why does the pressure and temperature increase during the compression section? A. Because potential and kinetic energy increase.
B. Because the compressor forms a divergent duct.
C. Because volume increases.
D. Because total internal energy decreases.
A
A. Because potential and kinetic energy increase.
4
Q
Q. How do the fuel classification Jet A and Jet A1 differ from those classified JP?
A. The Jet A and A1 have the same flash point as the JP fuels.
B. The Jet A and A1 have a lower freezing point than the JP fuels.
C. The Jet A and A1 are civilian classifications and the JP are military.
D. The Jet A and A1 have a higher degree of purity than the JP fuels.
A
C. The Jet A and A1 are civilian classifications and the JP are military.
5
Q
Q. Which of the following is NOT a symptom of a compressor stall/surge? A. Increasing turbine temperature. B. Increasing EPR. C. A surging/popping noise. D. Fluctuating RPM.
A
B. Increasing EPR.
6
Q
Q. What is the function of the bypass system in fuel filters?
A. To open when the fuel flow is low.
B. To open if the filter becomes blocked.
C. To close after start and open again on shutdown.
D. To open when the engine is starting or accelerating from low power/rpm.
A
B. To open if the filter becomes blocked.
7
Q
How are turbine discs usually cooled?
A. By feeding bypass air into the hot gas stream beyond the combustion outlet.
B. By feeding a supply of high pressure air from the compressor onto the face of the disc.
C. By spraying oil onto the face of the disc.
D. By feeding a low pressure air supply from the exhaust through and onto the face of the disc.
A
B. By feeding a supply of high pressure air from the compressor onto the face of the disc.
8
Q
Q. Which part of a turbine engine is most susceptible to damage as the result of an over-temp condition? A. The diffuser. B. The first stage turbine nozzle. C. The compressor inlet guide vanes. D. The exhaust duct.
A
B. The first stage turbine nozzle.
9
Q
Q. What are the two exhaust gas flows of a turbofan engine called?
A. Convergent and divergent.
B. Hot stream and cold stream.
C. External and internal.
D. Donut and core.
A
B. Hot stream and cold stream.
10
Q
Q. The primary function of air seals within a turbine engine is to:
A. prevent ram air from escaping the air inlet system.
B. prevent turbine outlet air from escaping the nozzle system.
C. pressurise labyrinth and carbon seals.
D. pressurise the compressor rotor area and cool the hot section areas.
A
C. pressurise labyrinth and carbon seals.
11
Q
Q. How is the residual temperature of the exhaust gases utilised?
A. Exhaust gases are used for airframe ice protection systems.
B. Exhaust gases are used for engine ice protection systems.
C. On turboprops the temperature of the exhaust gases can contribute to forward thrust, but on helicopters they serve no useful purpose.
D. It is not used at all, but rather it is lost to the atmosphere.
A
D. It is not used at all, but rather it is lost to the atmosphere.
12
Q
Q. How is RPM typically measured in a turboshaft engine?
A. By utilising an AC generator, three phase independent electrical system and synchronous motor.
B. By measuring compressor outlet pressure, since compressor outlet pressure is proportional to engine RPM.
C. By utilising a sensor which measures fan blade passage over a pick-up.
D. By utilising an electronic counter which measures the ignition pulses.
A
A. By utilising an AC generator, three phase independent electrical system and synchronous motor.
13
Q
Q. Turbine engine fuel systems commonly include a heat exchanger. One reason for this is to protect against:
A. the possibility of ice formation in the fuel.
B. absorption of atmospheric water vapour.
C. additives separating from the fuel.
D. overheating in the fuel lines.
A
A. the possibility of ice formation in the fuel.
14
Q
Q. What would normally be the first indication of power loss on a turboprop engine?
A. A reduction in air intake temperature and pressure.
B. A reduction in torque and exhaust gas temperature.
C. A reduction in RPM and propeller disconnection from the turbine shaft.
D. An increase in exhaust gas temperature and a reduction in fuel flow.
A
B. A reduction in torque and exhaust gas temperature.
15
Q
Q. Typically the lubrication systems of high bypass turbofan engines is _______ pressure _____ sump.
A. low dry
B. low wet
C. high wet
D. high dry
A
D. high dry
16
Q
Q. What is the most positive indication of engine light-up during start?
A. A rise in exhaust gas temperature.
B. A stabilising of the engine RPM.
C. A rise in oil pressure.
D. A reduction in fuel flow.
A
A. A rise in exhaust gas temperature.
17
Q
Q. The turbine temperature rising rapidly (unusually fast) towards the specified limit, is an indication of:
A. a wet start.
B. a hung (or false) start.
C. a hot start.
D. torching on start.
A
C. a hot start.
18
Q
Q. How are turbine discs usually cooled?
A. By feeding a low pressure air supply from the exhaust through and onto the face of the disc.
B. By spraying oil onto the face of the disc.
C. By feeding a supply of high pressure air from the compressor onto the face of the disc.
D. By feeding bypass air into the hot gas stream beyond the combustion outlet.
A
C. By feeding a supply of high pressure air from the compressor onto the face of the disc.
19
Q
Q. A combustion chamber’s liner and associated gas flow control and metering devices are designed to:
A. recirculate the air for repeat burning and to reduce CO emissions.
B. accelerate the gas flow and increase its pressure prior to the gases entry into the burning zone.
C. separate and control the gas flow for cooling and combustion and to create a region of low velocity recirculation of the air in the primary zone.
D. bleed off a portion of the gas flow for cooling of the turbine discs and sealing of the turbine shaft bearings.
A
C. separate and control the gas flow for cooling and combustion and to create a region of low velocity recirculation of the air in the primary zone.
20
Q
Q. All other factors remaining the same, which of the following conditions will increase thrust or torque from a turbine engine?
A. An increase in density altitude.
B. An increase in air intake pressure.
C. An increase in air intake temperature.
D. A decrease in intake air density.
A
B. An increase in air intake pressure.
21
Q
Q. What is the difference between a turboprop and a turboshaft?
A. With a turboprop the shaft is connected to a propeller gearbox, with a turboshaft the shaft is connected to something other than a propeller gearbox.
B. Turboprop engines are only fitted to fixed wing aircraft, while turboshaft engines are only fitted to helicopters.
C. There is no difference between turboprops and turboshafts, they are two names for the same type of engine.
D. With a turboprop the output from the engine is fed to the propeller through a gearbox, with a turboshaft the output shaft from the engine is connected directly to the propeller.
A
A. With a turboprop the shaft is connected to a propeller gearbox, with a turboshaft the shaft is connected to something other than a propeller gearbox.
22
Q
Q. Which of the following best describes self sustaining RPM during start?
A. The RPM at which the starter has created a steady acceleration of the engine core.
B. The RPM at which the turbine is generating enough torque to accelerate on its own.
C. The RPM at which the engine has settled at ground idle.
D. The RPM at which the gas temperature starts to reduce.
A
B. The RPM at which the turbine is generating enough torque to accelerate on its own.
23
Q
Q. For a gas at constant pressure, the temperature in a closed vessel will be directly proportional to its volume.
A. This is an expression of Boyle’s Law.
B. This is an expression of Charles’ Law.
C. This is an expression of Newton’s Second Law.
D. This is an expression of the first law of thermodynamics.
A
B. This is an expression of Charles’ Law.
24
Q
Q. What percentage of normal forward thrust is normally achieved and used for reverse thrust, during reverse thrust operation?
A. About 10%.
B. Somewhat less than 50%.
C. 100%.
D. About 135%.
A
B. Somewhat less than 50%.
25
Q. Which type of compressor can be described as having multiple stages of rotating aerofoil blades and fixed vanes, capable of large mass flow capacity, with high efficiency?
A. A centrifugal compressor.
B. A centripetal compressor.
C. An axial flow compressor.
D. A radial compressor.
C. An axial flow compressor.
26
Q. How does the temperature, density, pressure and velocity of a gas flow vary through a convergent duct at supersonic speed?
A. Temperature, density, pressure and velocity all increase.
B. Temperature, density and pressure all increase, while velocity decreases.
C. Temperature, density and pressure all decrease, while velocity increases.
D. Temperature, density, pressure and velocity all decrease.
B. Temperature, density and pressure all increase, while velocity decreases.
27
Q. When talking about turbine blades, what is "creep"?
A. The changing of the turbine blade shape due to FOD ingestion.
B. The permanent lengthening of the turbine blade due to high temperatures and centrifugal reaction.
C. The lateral movement of turbine blades within their mounting on the disc.
D. The cyclic lengthening and subsequent shortening of turbine blades each time the engine is started and shutdown.
B. The permanent lengthening of the turbine blade due to high temperatures and centrifugal reaction.
28
Q. What is the cause of creep in turbine blades?
A. High temperatures and centrifugal reaction.
B. Poor blade design.
C. An imperfection in the blade construction.
D. An overspeed or overtemp of the engine.
A. High temperatures and centrifugal reaction.
29
Q. What acronym is used to describe the ratio of turbine outlet pressure to compressor inlet pressure?
A. TIT.
B. EPT.
C. EGT.
D. EPR.
D. EPR.
To determine EPR, pressure measurements are taken by probes installed in the engine inlet and at the turbine exhaust. The data from these sensors is sent to a differential pressure transducer which then indicates the ratio of the two pressures on a flight deck EPR gauge. EPR system design automatically compensates for the effects of airspeed and altitude.
30
Q. Exhaust gas temperature (EGT) indication systems operates by means of:
A. a number of thermocouples or pyrometers, arranged in series.
B. a combination of thermometers and thermocouples, arranged in series.
C. a combination of pyrometers and/or pyrocouples, arranged linearly.
D. a number of thermocouples, arranged in parallel.
D. a number of thermocouples, arranged in parallel.
31
Q. Why is Specific Gravity (SG) considered when loading AVTUR into an aircraft?
A. In order to calculate the temperature of the fuel to ensure fuel icing does not become a problem later in flight.
B. Because the cost of fuel is determined by its SG, and airline accounting departments require this information for invoice reconciliation.
C. Because AVTUR is more susceptible to SG changes than other fuels, with a consequent change in its volatility.
D. Because fuel is loaded from the ground facility by volume (gallons or litres) and to convert volume to weight/mass (pound or kilograms) its SG is needed.
D. Because fuel is loaded from the ground facility by volume (gallons or litres) and to convert volume to weight/mass (pound or kilograms) its SG is needed.
32
Q. What are the primary functions of air seals in a turbine engine?
A. To pressurise the compressor rotor area and cool hot section areas.
B. To pressurise labyrinth and carbon seals and cool hot section areas.
C. To prevent ram air from escaping from the air inlet system.
D. To prevent turbine outlet gas flow escaping through the nozzle system.
B. To pressurise labyrinth and carbon seals and cool hot section areas.
33
Q. What is the primary function of the nozzle diaphragm?
A. To prevent choking of the heated gases flowing past this particular point, thereby reducing the possibility of turbine and compressor stall.
B. To increase the pressure of the exhaust gases.
C. To maximise the velocity of the gas exiting the combustion section ,and to direct the gases at the optimum angle onto the turbine blades.
D. To decrease the velocity of heated gases flowing past this particular point.
C. To maximise the velocity of the gas exiting the combustion section ,and to direct the gases at the optimum angle onto the turbine blades.
34
Q. With respect to the combustion process, how do turbine engines differ from reciprocating (piston) engines?
A. In turbine engines combustion takes place at near constant velocity, while in a reciprocating engine combustion takes place at an increasing temperature.
B. In turbine engines combustion takes place at near constant pressure, while in a reciprocating engine combustion takes place at a constant volume.
C. In turbine engines combustion takes place at near constant temperature, while in a reciprocating engine combustion takes place at a increasing pressure.
D. In turbine engines combustion takes place at near constant volume, while in a reciprocating engine combustion takes place at an increasing pressure.
B. In turbine engines combustion takes place at near constant pressure, while in a reciprocating engine combustion takes place at a constant volume.
35
Q. What is the ideal air/fuel ratio for combustion in a turbine engine?
A. 10:1
B. 15:1
C. 20:1
D. 30:1
B. 15:1
36
Q. Blocker doors moving to blank off the bypass fan air exit and redirect it forward on a high bypass turbofan, describes:
A. blade reversers.
B. clamshell reversers.
C. bucket reversers.
D. cold-stream reversers.
D. cold-stream reversers.
37
Q. Which instrument(s) indicate the thrust output of a turboprop engine?
A. Fuel flow.
B. Turbine temperature.
C. EPR.
D. Engine torque and RPM.
D. Engine torque and RPM.
38
Q. Equivalent horsepower is:
A. the power delivered to a helicopter main rotor gearbox on a turboshaft engine.
B. shaft horsepower plus the effect of residual jet thrust on a turboprop engine.
C. the power delivered to the propeller on a turboprop engine.
D. brake horsepower corrected for density changes.
B. shaft horsepower plus the effect of residual jet thrust on a turboprop engine.
39
Q. What would normally be the first indication of power loss on a turboprop engine?
A. A reduction in air intake temperature and pressure.
B. A reduction in torque and exhaust gas temperature.
C. An increase in exhaust gas temperature and a reduction in fuel flow.
D. A reduction in RPM and propeller disconnection from the turbine shaft.
B. A reduction in torque and exhaust gas temperature.
40
Which type of compressor can be described as short in length, spoke like in design, relatively simple to manufacture, with high compression per stage?
A. An axial flow compressor.
B. A turbine compressor.
C. A centrifugal compressor.
D. A centripetal compressor.
C. A centrifugal compressor.
41
Q. For a gas at constant pressure, the temperature in a closed vessel will be directly proportional to its volume. This is an expression of:
A. Boyle’s Law.
B. Charles' Law.
C. the first law of thermodynamics.
D. Newton’s First Law.
B. Charles' Law.
42
Q. Which instrument(s) indicate the thrust output of a turbofan engine?
A. EPR and/or N1.
B. Engine torque.
C. Turbine temperature.
D. Fuel flow
A. EPR and/or N1.
43
Q. For a gas at a constant temperature, the pressure in a closed vessel will be inversely proportional to its volume. This is an expression of:
A. Charles' Law.
B. Newton's Fourth Law.
C. Boyle's Law.
D. the second law of thermodynamics.
C. Boyle's Law.
44
Q. Which of the gas flows from a turbofan engine is used to generate reverse thrust?
A. Compressor flow by reversing the angle of the fan blades.
B. Combustion gases from reverse flow engines.
C. The hot exhaust gas from the core flow.
D. The cold stream flow from the bypass duct.
D. The cold stream flow from the bypass duct.
45
Q. In which one of the following ways does AVTUR differ from AVGAS?
A. AVTUR has a higher calorific value.
B. AVGAS has better self lubricating properties.
C. AVGAS has a higher specific gravity.
D. AVTUR is more volatile.
A. AVTUR has a higher calorific value.
46
Q. What check does a refueller perform to ensure that only acceptable levels of water are present in your Jet A1?
A. A visual check of a sample of the fuel delivered.
B. A chemical check involving a colour change if excess water is present.
C. A visual check of the sophisticated filter system.
D. Water content is continuously electronically monitored and an alarm will sound if excess water is present.
B. A chemical check involving a colour change if excess water is present.
47
Q. How is a demand by the pilot for more thrust handled mechanically in a turbine engine?
A. The power lever is connected to a fuel control unit which senses compressor inlet temperature, exhaust gas temperature, compressor outlet pressure and engine RPM.
B. The power lever is connected to the fuel pump which provides more fuel pressure. This is sensed by the fuel nozzle sensors which inject more fuel into the combustion chamber.
C. The power lever is connected to a fuel control unit which contains a governor to maintain RPM.
D. The power lever is connected to the fuel nozzle apparatus which allows more fuel into the burner.
A. The power lever is connected to a fuel control unit which senses compressor inlet temperature, exhaust gas temperature, compressor outlet pressure and engine RPM.
48
Q. Turbine blades used in modern turbine engines are generally:
A. Impulse-impulse type.
B. reaction type.
C. impulse type.
D. impulse-reaction type.
D. impulse-reaction type.
49
Q. In what ways are turbine engines and reciprocating (piston) engines similar?
A. Both types of engine use the same fuel.
B. Both types of engine use the same lubricating oil.
C. Both types of engine have the same power to weight ratio.
D. Both types of engine are internal combustion.
D. Both types of engine are internal combustion.
50
Q. What is the name of the rotating component of a centrifugal compressor that takes inlet air in at its centre and compresses it by centrifugal force? A. A turbine. B. A stator. C. A radiator. D. An impeller.
D. An impeller.
51
Q. Which of the following actions would be the correct if you experienced unacceptably slow acceleration of RPM on a turbine engine during start?
A. Open the thrust lever/throttle to the idle position.
B. Shut off the fuel supply and discontinue the start cycle.
C. Open the bleed valves to increase air flow through the compressor.
D. Increase the fuel flow.
B. Shut off the fuel supply and discontinue the start cycle.
52
Q. A turbofan engine in the cruise produces 60000 lb of thrust and burns 20000lb of fuel an hour. What is the specific fuel consumption (SFC) of the engine? SFC= Fuel flow/Thrust
A. 0.80
B. 0.33
C. 0.85
D. 0.25
B. 0.33
53
Q. On engine shutdown the dump valve: A. returns unburnt fuel to the primary manifold. B. holds residual fuel in the manifold ready for the next start. C. recirculates unused fuel back to the fuel tank. D. allows fuel in the manifold to drain away.
D. allows fuel in the manifold to drain away.
54
Q. Which instrument(s) indicate the thrust output of a turbofan engine? A. EPR and/or N1. B. Turbine temperature. C. Engine torque. D. Fuel flow
A. EPR and/or N1.
55
Q. Why are turbine engines often fitted with separate low and high energy ignition systems? A. Low energy igniters are used for abnormally adverse start conditions, such as during a start in very cold conditions or a high altitude relight. B. High energy igniters are used for abnormally adverse start conditions, such as during a start in very cold conditions or a high altitude relight. C. Low energy igniters are used on a normal start, but high energy igniters can be selected during a hung start. D. High energy igniters are used for continuous ignition situations, such as during takeoff.
B. High energy igniters are used for abnormally adverse start conditions, such as during a start in very cold conditions or a high altitude relight.
56
Q. What is the most critical engine condition instrument to monitor during engine start? A. N1. B. Fuel flow. C. Turbine temperature. D. EPR.
C. Turbine temperature.
57
Q. An advantage of a free turbine propulsion system would be: A. the ability to stop rotor blades while the engine is still running. B. slower engine starting and therefore less fuel use. C. the propellor turns the engine, so no gearbox is necessary. D. much cheaper to manufacture and service.
A. the ability to stop rotor blades while the engine is still running.
58
Q. Typically the lubrication systems of high bypass turbofan engines is _______ pressure _____ sump. A. high dry B. low dry C. high wet D. low wet
A. high dry
59
Q. What type of oil pump is generally utilised on turbine engines? A. A piston and plunger type. B. A sliding vane type. C. A variable displacement type. D. A gear type.
D. A gear type.
60
Q. A similarity between turbine and reciprocating engines is that: A. both are internal combustion engines. B. both engines have a continuous gas flow. C. both engines use the same type of fuel. D. both engines use the same type of lubricating oil.
A. both are internal combustion engines.
61
Q. What are the two types of inner section design of can-annular or annular combustion chambers? A. Through flow and reverse flow. B. High flow and low flow. C. Convergent and divergent. D. Segmented and baffled.
A. Through flow and reverse flow.
62
Q. Thrust delivered by a turbine engine is controlled by: A. the gear section of the high pressure fuel pump varying its outlet pressure. B. the bleed valves controlling the load on the engine. C. the fuel control unit varying the fuel flow. D. fuel pressure varying the angle of the inlet guide vanes.
C. the fuel control unit varying the fuel flow.
63
Q. Injecting water/methanol into the combustion chamber of a turboprop engine: A. increases the pressure of the air, thereby decreasing the density and therefore the weight (mass) of the gas flow through the engine. B. increases the velocity of the air, thereby increasing the weight (mass) of the gas flow through the engine. C. increases the temperature of the air, thereby decreasing the density and therefore the weight (mass) of the gas flow through the engine. D. cools the air, thereby increasing the density and therefore the weight (mass) of the gas flow through the engine.
D. cools the air, thereby increasing the density and therefore the weight (mass) of the gas flow through the engine.
64
Q. What are the primary functions of air seals in a turbine engine? A. To pressurise labyrinth and carbon seals and cool hot section areas. B. To prevent ram air from escaping from the air inlet system. C. To pressurise the compressor rotor area and cool hot section areas. D. To prevent turbine outlet gas flow escaping through the nozzle system.
A. To pressurise labyrinth and carbon seals and cool hot section areas.
65
Q. The most positive indication of engine light-up during the start cycle is: A. a rise in exhaust gas temperature. B. an oil pressure rise. C. a fuel flow rise. D. a rise in engine speed.
A. a rise in exhaust gas temperature.
66
Q. The torque output of a turboshaft engine will be increased with: A. a decrease in fuel flow and/or an decrease in compressor ratio. B. an increase in air intake temperature and/or an increase in fuel flow to the combustors. C. a decrease in turbine temperature and/or compressor delivery velocity. D. an increase in air intake pressure/density and/or an increase in fuel flow to the combustors.
D. an increase in air intake pressure/density and/or an increase in fuel flow to the combustors.
67
Q. Exhaust gas temperature (EGT) indication systems operates by means of: A. a combination of thermometers and thermocouples, arranged in series. B. a combination of pyrometers and/or pyrocouples, arranged linearly. C. a number of thermocouples, arranged in parallel. D. a number of thermocouples or pyrometers, arranged in series.
C. a number of thermocouples, arranged in parallel.
68
Q. If the relative humidity of the air through which an aircraft is flying increases significantly, thrust will tend to: A. remain the same, since the density of the air remains the same. B. increase, because of the increase in air density. C. decrease, because of the increase in air density. D. decrease, because of the decrease in air density.
D. decrease, because of the decrease in air density.
69
Q. How are modern turbine blades cooled in a turbofan engine? A. Fan air is blown over and through them. B. Bleed air from the compressor is blown over and/or through them. C. Secondary combustion air is blown over and through them. D. Oil is splashed over them.
B. Bleed air from the compressor is blown over and/or through them.
70
Q. What are the normal indications of a flame-out on a turbofan engine? A. EPR and fuel flow decrease, with an N1 and turbine temperature increase. B. EPR and fuel flow increase, with an N1 and turbine temperature decrease. C. EPR, N1, turbine temperature and fuel flow decrease. D. EPR and N1 decrease, with a turbine temperature and fuel flow increase.
C. EPR, N1, turbine temperature and fuel flow decrease.
71
Q. Which of the following is an advantage of a centrifugal compressor, compared to an axial flow compressor? A. A centrifugal compressor produces lower compressor discharge velocities relative to the intake velocity. B. A centrifugal compressor allows for a smaller engine diameter for a given mass flow capacity. C. A centrifugal compressor is more robust and relatively easier to manufacture. D. A centrifugal compressor can achieve higher overall compression ratios more efficiently.
C. A centrifugal compressor is more robust and relatively easier to manufacture.
72
Q. What are the three stages of turbine blade creep? A. First, second and third. B. Primary, secondary and tertiary. C. Status, gradual and final. D. Initial, developed and terminal.
B. Primary, secondary and tertiary.
73
Q. What will the effect on specific fuel consumption (SFC) and specific thrust be by increasing the compressor pressure ratio of an engine? A. SFC and specific thrust decreased. B. SFC decreased and specific thrust increased. C. SFC increased and specific thrust decreased. D. SFC and specific thrust increased.
B. SFC decreased and specific thrust increased.
74
Q. What percentage of normal forward thrust is normally achieved and used for reverse thrust, during reverse thrust operation? A. 100%. B. Somewhat less than 50%. C. About 135%. D. About 10%.
B. Somewhat less than 50%.
75
Q. What is the effect on SFC of increasing compressor pressure ratio for a given fuel flow? A. SFC will decrease because an increase in compressor outlet pressure will cause a decreased turbine inlet temperature. B. SFC will increase because an increase in compressor outlet pressure will cause a decrease in outlet velocity. C. SFC will decrease because increased compressor discharge pressure generates a higher turbine inlet temperature and increases engine thrust. D. SFC will increase because increased compressor discharge pressure generates a lower turbine inlet temperature and increases engine thrust.
C. SFC will decrease because increased compressor discharge pressure generates a higher turbine inlet temperature and increases engine thrust.
76
Q. What is the primary advantage of an annular combustion chamber design? A. Less structural complexity required. B. Only one fuel spray nozzle and ignitor is required, thereby reducing weight. C. Optimum fuel spray patterns can be obtained. D. Maximum utilisation of space and minimum length and diameter.
D. Maximum utilisation of space and minimum length and diameter.
77
Q. What is the normal shape of the duct formed by the exhaust nozzle on a subsonic turbofan engine? A. Divergent. B. Constant diameter. C. Divergent-convergent. D. Convergent.
D. Convergent.
78
Q. After an engine fire has been extinguished, no attempt should be made to restart the engine. Apart from the fact that a restart would re-introduce fuel and ignition to the engine, what other reason is of considerable importance? A. The engine will be starved of oil. B. The extinguishing system will be diminished. C. A Mayday call would have been made. D. The engine will be contaminated with extinguishant.
B. The extinguishing system will be diminished.
79
Q. Why is it necessary for a starting system to uniformly accelerate the turbine engine from rest up to a speed at which the gas flow through the turbine provides sufficient torque to "take over"? A. To prevent the build-up of fuel in the combustion chamber from the time the engine starts turning. B. To give a cooler start and longer engine life. C. To give the combustion chambers the correct air flow for the combustion process to continue acceleration to idle speed. D. To give a hotter start but reduced time spent at higher temperatures and therefore a longer engine life.
C. To give the combustion chambers the correct air flow for the combustion process to continue acceleration to idle speed.
80
How does the temperature, density, pressure and velocity of a gas flow vary through a divergent duct at supersonic speed? A. Temperature and pressure both increase, while velocity and density decreases. B. Temperature, density, pressure and velocity all increase. C. Temperature, density and pressure both decrease, while velocity increases. D. Temperature, density, pressure and velocity all decrease.
C. Temperature, density and pressure both decrease, while velocity increases.
81
Q. With respect to the mechanical efficiency, how do turbine engines differ from reciprocating (piston) engines? A. There is no difference between the two engine types with respect to mechanical efficiency. B. The reciprocating engine is more mechanically efficient. C. The respective mechanical efficiency of the two engine types depends on the prevailing operating environment. D. The turbine engine is more mechanically efficient.
D. The turbine engine is more mechanically efficient.
82
Q. Which components of a turbojet engine contribute to rearward acting forces? A. The diffuser and the combustion chamber. B. The turbine and the compressor. C. The compressor and the exhaust cone. D. The turbine and the propelling nozzle.
D. The turbine and the propelling nozzle.
83
Q. A double stage centrifugal compressor typically has a compression ratio of up to: A. 15:1. B. 20-30:1. C. 1:1. D. 10:1.
A. 15:1.
84
Q. What are the two main types of intake on turbofan engined aircraft? A. Centreline and offset. B. Divided and pitot. C. Shielded and unshielded. D. Convergent and divergent.
B. Divided and pitot.
85
Q. How does the pressure, temperature and velocity change across a stage of an axial compressor? A. Pressure, temperature and velocity all decreases across both the rotor and the stator. B. Pressure and temperature both decrease across both the rotor and the stator, while velocity increases across the stator and decreases across the rotor. C. Pressure and temperature both increase across both the rotor and the stator, while velocity decreases across the stator and increases across the rotor. D. Pressure, temperature and velocity all increases across both the rotor and the stator.
C. Pressure and temperature both increase across both the rotor and the stator, while velocity decreases across the stator and increases across the rotor.
86
Q. How does a turboprop engine compare to a reciprocating engine of the same power output? A. Turboprop engines are less costly to purchase. B. Turboprop engines are less reliable. C. Turboprop engines are lighter. D. Turboprop engines lose power more rapidly as TAS increases.
C. Turboprop engines are lighter.
87
Q. How do fuel classifications Jet A and Jet A1 differ from those classified JP? A. The Jet A and Jet A1 are civilian classifications and JP is a military classification. B. Jet A and Jet A1 have lower freezing points than JP classified fuels. C. Jet A and Jet A1 have a higher purity than JP classified fuels. D. Jet A and Jet A1 have higher flash points than JP classified fuels.
A. The Jet A and Jet A1 are civilian classifications and JP is a military classification.
88
Q. The primary function of a turbine engine’s lubrication system is to: A. prevent metal to metal contact. B. cool the internal bearings. C. protect the turbine blades from corrosion. D. clean metal particles from the turbine shaft bearings.
A. prevent metal to metal contact.
89
Q. Pressure-thrust comes from flow which becomes sonic at the throat of a ________________ exhaust nozzle. A. convergent-divergent B. convergent C. divergent-convergent D. divergent
A. convergent-divergent
90
Q. The shape of the intake duct on a turbofan engine is: A. fractious. B. convergent. C. constant diameter. D. divergent.
D. divergent.
91
Q. With increasing temperature and high RPM, turbine blades lengthen. When the engine shuts down the blades return to normal size. With time, the blades will not return to quite the old size. What is this phenomenon called? A. Fatigue. B. Creep. C. Hysteresis. D. Expansion.
B. Creep.
92
Q. A prominent cockpit indication of a compressor stall during engine start-up would be a: A. poor acceleration rate and high EPR. B. surging noise and fluctuating oil pressure. C. sudden increase in fuel flow, fluctuating EGT and high RPM. D. surging noise, a rise on EGT and fluctuations in RPM.
D. surging noise, a rise on EGT and fluctuations in RPM.
93
Q. What additional airframe components are often added to turboprop and turboshaft engined aircraft? A. Shockwave inducing baffles. B. Vortex generators to impart swirl to the intake air in order to reduce the possibility of FOD ingestion. C. Air intake protection devices such as particle separators, screens or bird catchers. D. Geared superchargers.
C. Air intake protection devices such as particle separators, screens or bird catchers.
94
Q. What is the name given to the permanent lengthening (elongation) of turbine blades? A. Stretch. B. Distension. C. Creep. D. Rubbing.
C. Creep.
95
Q. Pressure-thrust comes from flow which becomes sonic at the throat of a ________________ exhaust nozzle. A. divergent-convergent B. convergent-divergent C. divergent D. convergent
B. convergent-divergent
96
Q. What type of oil pump is generally utilised on turbine engines? A. A sliding vane type. B. A piston and plunger type. C. A gear type. D. A variable displacement type.
C. A gear type.
97
Q. With increasing temperature and high RPM, turbine blades lengthen. When the engine shuts down the blades return to normal size. With time, the blades will not return to quite the old size. What is this phenomenon called? A. Fatigue. B. Hysteresis. C. Creep. D. Expansion.
C. Creep.
98
Q. There are three general types of combustion chamber. The most easily serviced is totally external to the engine, the second is a dual ring system and the third is an efficient combination of the two others. Which of the following lists the three types, in the order described? A. Can, Annular and Can-annular. B. Can-annular, Can and Annular. C. Can-annular, Annular and Can. D. Can, Can-annular and Annular.
A. Can, Annular and Can-annular.
99
Q. Fuel exhaustion, compressor stall, high altitude flight, severe turbulence and high speed manoeuvres can all cause what phenomenon in a jet engine? A. Flame-out. B. Surging. C. Over-temperature. D. Reverse flow.
A. Flame-out.
100
Q. What is Boyle's Law? A. For gas at a constant pressure, the volume of a given mass of gas is directly proportional to its absolute temperature. B. For gas at a constant volume, the pressure of a given mass of gas is directly proportional to its absolute temperature. C. For a gas at a constant temperature, the pressure in a closed vessel will be inversely proportional to its volume. D. Equal volumes of ideal or perfect gases, at the same temperature and pressure, contain the same number of particles, or molecules.
C. For a gas at a constant temperature, the pressure in a closed vessel will be inversely proportional to its volume.
101
Q. Typically, the fuel system in a turbine engine will contain filters just before and just after the main fuel pump. The high pressure filter will contain a special safety feature. What is it? A. A bypass system that will open if the filter becomes blocked. B. A bypass system that operates during engine start to provide higher fuel flow to the nozzles. C. A fusable plug that melts if the temperature gets too high. D. A bypass system that will operate when the fuel flow is low.
A. A bypass system that will open if the filter becomes blocked.
102
Q. Exhaust gas temperature (EGT) indication systems operates by means of: A. a number of thermocouples, arranged in parallel. B. a number of thermocouples or pyrometers, arranged in series. C. a combination of pyrometers and/or pyrocouples, arranged linearly. D. a combination of thermometers and thermocouples, arranged in series.
A. a number of thermocouples, arranged in parallel.
103
Q. What is Charles' Law? A. Equal volumes of ideal or perfect gases, at the same temperature and pressure, contain the same number of particles, or molecules. B. For gas at a constant volume, the pressure of a given mass of gas is directly proportional to its absolute temperature. C. For gas at a constant temperature, the pressure and the volume of a gas are inversely proportional. D. For gas at a constant pressure, the volume of a given mass of gas is directly proportional to its absolute temperature.
D. For gas at a constant pressure, the volume of a given mass of gas is directly proportional to its absolute temperature.
104
Q. How do bucket reversers function? A. By blocker doors in the bypass duct moving to blank off the cold fan air redirecting it forward. B. By blocker doors inside the exhaust duct moving to blank off the hot exhaust gases redirecting them forward. C. By blocker doors external to the exhaust duct moving to blank off the hot exhaust gases redirecting them forward. D. By cascade vanes in the nacelle surrounding the bypass duct opening to allow the cold fan air to flow outward and forward.
C. By blocker doors external to the exhaust duct moving to blank off the hot exhaust gases redirecting them forward.
105
Q, How do clamshell reversers function? A. By blocker doors inside the exhaust duct moving to blank off the hot exhaust gases redirecting them forward. B. By blocker doors in the bypass duct moving to blank off the cold fan air redirecting it forward. C. By cascade vanes in the nacelle surrounding the bypass duct opening to allow the cold fan air to flow outward and forward. D. By blocker doors external to the exhaust duct moving to blank off the hot exhaust gases redirecting them forward.
A. By blocker doors inside the exhaust duct moving to blank off the hot exhaust gases redirecting them forward.
106
Q. Newton’s third law states that: A. a body will remain in a state of uniform motion unless acted on by an external force. B. for every action there is an equal and opposite reaction. C. force equals mass times acceleration. D. what goes up must come down.
B. for every action there is an equal and opposite reaction.
107
Q. What additional airframe components are often added to turboprop and turboshaft engined aircraft? A. Vortex generators to impart swirl to the intake air in order to reduce the possibility of FOD ingestion. B. Geared superchargers. C. Air intake protection devices such as particle separators, screens or bird catchers. D. Shockwave inducing baffles.
C. Air intake protection devices such as particle separators, screens or bird catchers.
108
Q. Newton's first law states that: A. for every action there is an equal and opposite reaction. B. force equals mass times acceleration. C. a body will remain in a state of uniform motion unless acted on by an external force. D. PV = NRT
C. a body will remain in a state of uniform motion unless acted on by an external force.
109
Q. Turbine engine ignition systems have both high and low energy capabilities. What is the purpose of the high energy system? A. For use in icing conditions. B. For takeoff in heavy rain. C. For use in turbulent conditions. D. For in-flight engine starting.
D. For in-flight engine starting.
110
Q. Turbine fuel with a civilian classification Jet A1 is known as _______ in the United States and has the military classification \_\_\_\_\_\_. A. JP-8 F-80 B. JP-5 F-35 C. JP-4 F-40 D. JP-40 F-45
B. JP-5 F-35
111
Q. Over-temperature in a turbine engine is considered the most critical: A. in the flame tube or combustion chamber. B. in the area between the engine casing and nacelle structure. C. at the propelling nozzle. D. at the first stage turbine assembly
D. at the first stage turbine assembly
112
Q. Which of the following types of turbine engine can be described as a ducted propeller? A. A turboprop. B. A turbofan. C. An aft fan, or hyper ducted fan. D. A propfan.
B. A turbofan.
113
Q. How do supersonic air intake ducts decelerate the airflow to a subsonic condition prior to compressor entry? By their convergent design. B. By employing devices which cause shockwaves. By employing drag devices such as bellows. By their divergent design.
B. By employing devices which cause shockwaves.
114
Q. Turbine powered helicopters and agricultural aircraft are often left running during short stops: A. to save time since up to five minutes is required for temperatures to stabilise after start. B. because the stop/start cycles are where most damage/wear is done to engines. C. to save fuel, because fuel usage is highest during shutdowns and starts. D. to save battery life because the drain is so high during starts.
B. because the stop/start cycles are where most damage/wear is done to engines.
115
Q. Which of the following statements regarding Specific Fuel Consumption (SFC) is correct? A. SFC increases with altitude, since RPM is increased to maintain a given thrust. B. SFC is a measure of engine efficiency. When SFC is high, engine efficiency and therefore fuel economy is high. C. SFC decreases if the compressor is dirty or damaged. D. SFC is a measure of engine efficiency. When SFC is low, engine efficiency and therefore fuel economy is high.
D. SFC is a measure of engine efficiency. When SFC is low, engine efficiency and therefore fuel economy is high.
116
Q. Newton's second law states that: A. opposites attract. B. for every action there is an equal and opposite reaction. C. force equals mass times acceleration. D. a body will remain in a state of uniform motion unless acted on by an external force.
C. force equals mass times acceleration.
117
Q. Which instrument(s) indicate the thrust output of a turbofan engine? A. Turbine temperature. B. EPR and/or N1. C. Fuel flow D. Engine torque.
B. EPR and/or N1.
118
Q. When talking about turbine blades, what is "creep"? A. The permanent lengthening of the turbine blade due to high temperatures and centrifugal reaction. B. The lateral movement of turbine blades within their mounting on the disc. C. The cyclic lengthening and subsequent shortening of turbine blades each time the engine is started and shutdown. D. The changing of the turbine blade shape due to FOD ingestion.
A. The permanent lengthening of the turbine blade due to high temperatures and centrifugal reaction.
119
Q. Which of the following actions would be the correct if you experienced unacceptably slow acceleration of RPM on a turbine engine during start? A. Open the bleed valves to increase air flow through the compressor. B. Increase the fuel flow. C. Open the thrust lever/throttle to the idle position. D. Shut off the fuel supply and discontinue the start cycle.
D. Shut off the fuel supply and discontinue the start cycle.
120
Q. The primary function of a turbine engine’s lubrication system is to: A. protect the turbine blades from corrosion. B. prevent metal to metal contact. C. cool the internal bearings. D. clean metal particles from the turbine shaft bearings.
B. prevent metal to metal contact.
121
Q. Typically the lubrication systems of high bypass turbofan engines is _______ pressure _____ sump. A. high dry B. high wet C. low dry D. low wet
A. high dry
122
Q. Which of the following is an advantage of a free turbine propulsion system? A. With a free turbine propulsive system the shaft is connected directly to the propeller or helicopter rotor, so no gearbox is required, thereby significantly reducing the overall weight of the respective aircraft type. B. With a free turbine propulsive system there is significantly less complexity, so the engine is easier and cheaper to manufacture. C. With a free turbine propulsive system the start is much slower and therefore less fuel is used during the start. D. With a free turbine propulsive system the propellor or helicopter rotor can be held stationary while the engine is started, or stopped while the engine is still running.
D. With a free turbine propulsive system the propellor or helicopter rotor can be held stationary while the engine is started, or stopped while the engine is still running.
