Mancomunidad 15

1. What is the principle of the conservation of energy?. a. The principle of the conservation of energy is that energy cannot be created nor destroyed. b. The principle of the conservation of energy is that the engine needs to be well-designed to conserve energy. c. The principle of the conservation of energy is that insulating the engine to prevent heat energy losses.

2. A piston engine is rated in brake horsepower (BHP). How are turboprop and turboshaft engines rated?. a. Turboprop and turboshaft engines are also rated in BHP. b. Turboprop and turboshaft engines are rated in thrust horsepower (THP). c. Turboprop and turboshaft engines are rated in shaft horsepower (SHP).

3. What is required to start a ramjet?. a. An electrical starter motor is required to start a ramjet. b. Forward motion is required to start a ramjet. c. A spark igniter only is required to start a ramjet.

4. What is the formula for potential energy?. a. Epot 12mv2 (1½ mass x velocity2). b. Epot ma (mass acceleration). c. Epot=mgh (mass x gravity x height).

5. In addition to lubrication, what is an advantage of squeeze film lubrication?. a. Squeeze film lubrication dampens vibrations from the bearing to the housing. b. Squeeze film lubrication reduces the temperature in the bearing housing. c. Squeeze film lubrication cleans the bearing and housing assembly.

6. From where does the air pressure in the oil tank come?. a. The air pressure in the oil tank comes from the bleed air. b. The air pressure in the oil tank comes from the scavenge oil from the labyrinth seals. c. The air pressure in the oil talk comes from the fan air.

7. At least how much bigger is the scavenge pump element than the pressure pump?. a. To detect early signs of main oil cooler failure. b. To detect early signs of main filter failure. c. To detect early signs of main bearing failure.

8. What type of lubrication system is used with an inverted oil system?. a. An inverted oil system uses a wet sump system. b. An inverted oil system uses a dry sump system. c. An inverted oil system uses either a wet sump or dry sump system.

9. What is the 'rich blowout'?. a. The phenomenon of 'rich blowout' refers to the pressure in the fuel filter becoming so high that the bypass valve opens. b. The phenomenon of 'rich blowout' refers to the mixture in the burner chamber becoming too rich to remain alight. c. The phenomenon of 'rich blowout' refers to the feed pressure from the Fuel pump becoming too high.

10. Which channel of the EEC is in control of the engine?. a. The channels alternate on each engine start if they are equally healthy. b. Channel A is always in control if they are equally healthy. c. Channel B is always in control, and the pilot can switch on Channel A at any time.

11. What is true of a kinetic knife when compared to a half-ball valve?. a. Compared to a half-ball valve, a kinetic knife is less susceptible to dirt blockage. b. Compared to a half-ball valve, a kinetic knife is less complex. c. Compared to a half-ball valve, a kinetic knife is more sensitive to pressure changes.

12. How can you increase fuel flow to the burners?. a. To increase fuel flow to the burners, either increase the pressure drop across the orifice or increase the size of the orifice. b. To increase fuel flow to the burners, either increase the pressure drop across the orifice or decrease the size of the orifice. c. To increase fuel flow to the burners, either decrease the pressure drop across the orifice or increase the size of the orifice.

13. What factor is kept constant when metering fuel with a fuel metering valve?. a. A fuel metering valve keeps the metering valve opening constant when metering fuel. b. A fuel metering valve keeps the pressure drop over the metering valve constant when metering fuel. c. A fuel metering valve keeps the specific gravity constant when metering fuel.

14. What type of seal is commonly used to seal the engine thrust bearing chamber?. a. Labyrinth seals are commonly used to seal the engine thrust-bearing chamber. b. Ring seals are commonly used to seal the engine thrust-bearing chamber. c. Carbon seals are commonly used to seal the engine thrust-bearing chamber.

15. Which of the following seal types uses a film of oil and a fin to seal air pressure inside a bearing chamber?. a. Carbon seals use a film of oil and a fin to seal air pressure inside a bearing chamber. b. Labyrinth seals use a film of oil and a fin to seal air pressure inside a bearing chamber. c. Hydraulic seals use a film of oil and a fin to seal air pressure inside a bearing chamber.

16. What kind of cooling directs the cooling air at 90° to the internal surface of the blade?. a. Convection cooling. b. Impingement cooling. c. Film cooling.

17. When does the sprag clutch assembly on a starter motor engage?. a. The sprag clutch assembly on a starter motor engages manually as soon as the rotor starts to turn and disengages automatically as soon as the engine turns faster than the starter motor. b. The sprag clutch assembly on a starter motor engages automatically as soon as the rotor starts to turn but is disengaged manually as soon as the engine turns faster than the starter motor. c. The sprag clutch assembly on a starter motor engages automatically as soon as the rotor starts to turn and disengages automatically as soon as the starter motor turns faster than the engine.

18. What is the purpose of the trembler switch on a high-energy ignition unit (HEIU)?. a. The trembler switch on an HEIU schedules the spark timing at the igniter plug. b. The trembler switch on an HEIU breaks up the DC input power so the transformer works. c. The trembler switch on an HEIU smooths the AC input power so the capacitor charges.

19. What should be the starter motor status if an engine needs to be restarted at altitude?. a. The starter motor is never required when an engine needs to be restarted at altitude. b. The starter motor may be required when an engine needs to be restarted at altitude. c. The starter motor is always required when an engine needs to be restarted at altitude.

20. How should igniter plugs be cleaned?. a. Igniter plugs should be cleaned with a solvent and soft non-metallic brush. b. Igniter plugs should be cleaned with abrasive grit blast. c. Igniter plugs should be cleaned with a steel brush.

21. What parameter of the output of a tachogenerator is used to indicate RPM?. a. The voltage of the output of a tachogenerator is used to indicate RPM. b. The phase of the output of a tachogenerator is used to indicate RPM. c. The frequency of the output of a tachogenerator is used to indicate RPM.

22. How does a torque sensor measure torque?. a. A torque sensor measures torque by measuring the twist in the gas generator shaft. b. A torque sensor measures torque by measuring the twist in the propeller shaft. c. A torque sensor measures torque by measuring the variable reluctance in a phonic wheel.

23. What units of measurement is used for engine pressure ratio (EPR)?. a. EPR is displayed in pounds per square inch (PSI). b. EPR is displayed in Pascals (Pa). c. No units are used to display EPR.

24. What is the purpose of a ballast resistor, usually a carbon resistor, in an exhaust gas temperature (EGT) system?. a. The purpose of a ballast resistor in an EGT system is to compensate for changes in temperature of the whole EGT system. b. The purpose of a ballast resistor in an EGT system is to damp the EGT signal in case of rapid change. c. The purpose of a ballast resistor in an EGT system is to protect the indicator from high voltage.

25. What pressures are used to calculate engine pressure ratio (EPR)?. a. Total pressures are used to calculate EPR. b. Only static pressures are used to calculate EPR. c. Only dynamic (ram) pressures are used to calculate EPR.

26. What is integrated engine pressure ratio (IEPR)?. a. IEPR is EPR that uses fan outlet pressure instead of turbine discharge pressure. b. IEPR is EPR that uses a combination of turbine discharge and fan outlet pressures. c. IEPR is EPR calculated electronically instead of mechanically.

27. What type of pressure do oil low-pressure switches usually detect?. a. Differential pressure. b. Ambient pressure. c. Absolute pressure.

28. What is the purpose of a thermal management system (TMS) in a turboelectric propulsion system?. a. The TMS in a turboelectric propulsion system controls the temperature of the system and prevents the entire system from overheating. b. The TMS in a turboelectric propulsion system is to help the electric motor get to full operating temperature as quickly as possible. c. The TMS in a turboelectric propulsion system is to reduce the weight of the system by allowing smaller battery packs to be used.

29. What is the primary design objective of a propfan engine?. a. The primary design objective of a propfan engine is to attain high forward speeds. b. The primary design objective of a propfan engine is to minimize maintenance requirements. c. The primary design objective of a propfan engine is to optimize fuel economy while maintaining speed and performance.

30. Which of the following actions can damage a single-shaft turboprop engine?. a. Damage can be done to a single-shaft turboprop engine if it is started with the propeller in the fine-pitch position. b. Damage can be done to a single-shaft turboprop engine if it is shut down with the propeller in the feather position. c. Damage can be done to a single-shaft turboprop engine if it is shut down with the propeller in the fine pitch position.

31. What is the flight-fine pitch angle of a propeller fitted to a turboprop engine regulation system?. a. The flight-fine pitch-angle of a propeller fitted to a turboprop engine regulation system is the minimum propeller blade angle during flight. b. The flight-fine pitch-angle of a propeller fitted to a turboprop engine regulation system is the maximum propeller blade angle during flight. c. The flight-fine pitch-angle of a propeller fitted to a turboprop engine regulation system is the same propeller blade angle as the feathered position.

32. What does an increase in power do to the engine torque and propeller RPM in cruise?. a. An increase in power causes the propeller RPM to remain constant and the torque to increase. b. An increase in power causes the torque to increase and the propeller RPM to increase. c. An increase in power causes the torque to remain constant and the propeller RPM to increase.

33. What is the configuration if the planet gears rotate around the sun gear on a turboprop reduction gear?. a. If the planet gears rotate around the sun gear, the outer ring is fixed. b. If the planet gears rotate around the sun gear, the outer ring is rotating. c. If the planet gears rotate around the sun gear, there is no outer ring.

34. What position must the propeller of a free-turbine turboprop engine be in, to start?. a. A free-turbine turboprop engine can only be started with the propeller in the feather position. b. A free-turbine turboprop engine can only be started with the propeller in the ground fine position. c. A free-turbine turboprop engine can be started with the propeller either in the feather or ground fine position.

35. What accommodates a helicopter's angular misalignment between the engine and main gearbox?. a. On a helicopter, angular misalignment between the engine and the main gearbox is accommodated by a disc coupling. b. On a helicopter, angular misalignment between the engine and the main gearbox is accommodated by rubber engine mounts. c. On a helicopter, angular misalignment between the engine and the main gearbox is accommodated by spherical bearings.

36. What absorbs the energy generated by the gas generator in most helicopters?. a. In most helicopters, the energy generated by the gas generator is absorbed by the HP turbine. b. In most helicopters, the energy generated by the gas generator is absorbed by the propeller. c. In most helicopters, the energy generated by the gas generator is absorbed by the free-power turbine.

37. What type of engine is used in helicopters?. a. A turboprop engine. b. A turbofan engine. c. A turboshaft engine.

38. When does the APU start to rotate after APU start is initiated?. a. The APU starts to rotate when the intake door is fully open. b. The APU starts to rotate immediately after the BITE check has finished. c. The APU starts to rotate when the intake door is fully closed.

39. What is the function of an APU plenum chamber?. a. An APU plenum chamber ensures that exhaust gas is ejected clear of the airframe. b. An APU plenum chamber collects intake air before the air enters the compressor. c. An APU plenum chamber collects and cools bleed air.

40. Which statement is true regarding any normal APU shutdown procedure?. a. Once the APU shutdown sequence is initiated, the pneumatic load is removed by the ECB by closing the IGVs and the APU bleed valve and opening the surge control valve. b. Once the APU shutdown sequence is initiated, the pneumatic load is removed by the ECB by opening the IGVs and the APU bleed valve and closing the surge control valve. c. Once the APU shutdown sequence is initiated, the pneumatic load is removed by manually closing the IGVs and the APU bleed valve and opening the surge control valve.

41. How many tension bolts typically attach the engine front mount to the aircraft pylon?. a. Typically, two tension bolts attach the engine front mount to the aircraft pylon. b. Typically, four tension bolts attach the engine front mount to the aircraft pylon. c. Typically, six tension bolts attach the engine front mount to the aircraft pylon.

42. What is the purpose of the compressor casing abradable linings?. a. Compressor casing abradable linings are to maintain minimum rotor tip clearance. b. Compressor casing abradable linings are to wear flown compressor blade tips to ensure minimum blade tip clearance. c. Compressor casing abradable linings are to minimise casing wear on engine installation.

43. What does the beta mode in the engine mechanical control system refer to?. a. The beta mode in the engine mechanical control system refers to a mode where the propeller is feathered. b. The beta mode in the engine mechanical control system refers to a mode where both power and propeller blade angle are directly controlled. c. The beta mode in the engine mechanical control system refers to a mode where the HP shutoff cock is opened or closed.

44. What is equivalent shaft horsepower (ESHP)?. a. ESHP is shaft horsepower (SHP) plus exhaust jet thrust. b. ESHP is equivalent to the piston engine power. c. ESHP is the comparison of thrust to SHP.

45. What happens to thrust with increasing altitude with a fixed throttle setting?. a. With increasing altitude with a fixed throttle setting, thrust decreases. b. With increasing altitude with a fixed throttle setting, thrust increases. c. With increasing altitude with a fixed throttle setting, thrust remains constant.

46. When is propulsive efficiency highest?. a. Propulsive efficiency is highest when exhaust velocity is much higher than inlet velocity. b. Propulsive efficiency is highest when inlet and exhaust velocities are very close to each other. c. Propulsive efficiency is highest when inlet velocity is much greater than exhaust velocity.

47. What does the bypass ratio (BPR) of a turbine engine mean?. a. The BPR of a turbine engine is the ratio of secondary airflow to primary airflow. b. The BPR of a turbine engine is the ratio of primary airflow to secondary airflow. c. The BPR of a turbine engine is the ratio of core engine diameter to fan diameter.

48. Assuming fixed airspeed, altitude and power lever position and a non-flat-rated engine, how does decreasing outside air temperature (OAT) affect the engine's ability to produce thrust?. a. With decreasing OAT, the engine produces more thrust. b. With decreasing OAT, the engine will produce the same amount of thrust. c. With decreasing OAT, the engine will produce less thrust.

49. Of what is external efficiency a measure?. a. External efficiency is a measure of how effectively kinetic energy is converted into useful work. b. External efficiency is a measure of how efficient the propelling nozzle is. c. External efficiency is a measure of the efficiency of conversion of SHP to propeller thrust.

50. How do you verify the correct amount of agent content in an engine fire extinguisher?. a. The correct amount of agent content in an engine fire extinguisher can be verified by removing and weighing the extinguisher. b. The correct amount of agent content in an engine fire extinguisher can be verified by reading the pressure indicated on the extinguisher. c. The correct amount of agent content in an engine fire extinguisher can be verified by viewing the sight glass on the extinguisher.

51. What maintenance or repair can you do if an engine's continuous loop firewire is found to have a nick or kink?. a. If an engine's continuous loop firewire is found to have a nick or kink, the firewire must be replaced. b. If an engine's continuous loop firewire is found to have a nick or kink, the damage can be carefully filed out. c. If an engine's continuous loop firewire is found to have a nick or kink, the damage can be cut out and re-joined by soldering.

52. What does it mean, if a yellow disc is missing from the side of the fuselage or pylon?. a. On some aircraft, if a yellow disc is missing from the side of the fuselage or pylon, this means the pilot has activated the engine fire extinguisher. b. On some aircraft, if a yellow disc is missing from the side of the fuselage or pylon, this means the engine fire extinguisher is serviceable. c. On some aircraft, if a yellow disc is missing from the side of the fuselage or pylon, this means the engine fire extinguisher has overheated.

53. What is the primary purpose of debris particle examination?. a. The primary purpose of debris particle examination is to identify the size and quantity of particles. b. The primary purpose of debris particle examination is to determine the shape of particles. c. The primary purpose of debris particle examination is to determine the source of particles.

54. What is the primary health indication to be monitored during an engine run?. a. The primary health indication to be monitored during an engine run is the fuel flow. b. The primary health indication to be monitored during an engine run is the oil pressure. c. The primary health indication to be monitored during an engine run is the EGT.

55. Which cleaning method is most effective for the turbine section?. a. Abrasive grit is the most effective cleaning method for the turbine section. b. Abrasive grit and fluid wash are equally effective cleaning methods for the turbine section. c. Fluid wash is the most effective cleaning method for the turbine section.

56. What does a power assurance check on a turbine engine tell you?. a. A power assurance check on a turbine engine tells you if the engine fuel control can control all of its functions. b. A power assurance check on a turbine engine tells you if the engine can deliver the certified take-off thrust. c. A power assurance check on a turbine engine tells you that if the engine delivers the correct power to the accessory systems.

57. What part of a fan blade is the most critical for damage?. a. The most critical area for damage on a fan blade is at the blade root. b. The most critical area for damage on a fan blade is at the blade's tip. c. The most critical area for damage on a fan blade is at the blade's leading edge.

58. Which of these is a sub-procedure for non-engine system checks or fault confirmations?. a. A pneumatic power system check is a sub-procedure for non-engine system checks or fault confirmations. b. An engine system test is a sub-procedure for non-engine system checks or fault confirmations. c. An air-conditioning system check is a sub-procedure for non-engine system checks or fault confirmations.

59. What type of maintenance often involves giving components a pre-established 'life' in hours, calendar time, or operational cycles?. a. Corrective maintenance often involves giving components a pre-established 'life' in hours, calendar time, or operational cycles. b. Scheduled maintenance often involves giving components a pre-established 'life' in hours, calendar time, or operational cycles. c. On-condition maintenance often involves giving components a pre-established 'life' in hours, calendar time, or operational cycles.

60. What is the purpose of inhibiting the fuel system for engine storage?. a. The purpose of inhibiting the fuel system for engine storage is to prevent fuel from evaporating and leaving a sticky deposit. b. The purpose of inhibiting the fuel system for engine storage is to prevent water in the fuel from icing. c. The purpose of inhibiting the fuel system for engine storage is to prevent water in the fuel from causing corrosion.

61. What does inhibiting of a fuel control unit mean?. a. Inhibiting a fuel control unit means to fill with corrosion-preventive oil. b. Inhibiting a fuel control unit means dismantling it down to its component parts. c. Inhibiting a fuel control unit means locking the rotating parts to prevent damage during transit.

62. What is the main reason that envelopes on sealed uninstalled engines should be inspected monthly?. a. Envelopes on sealed engines should be inspected monthly to ensure that the humidity within the envelope is satisfactory. b. Envelopes on sealed engines should be inspected monthly to ensure that the envelope is not broken open. c. Envelopes on sealed engines should be inspected monthly to ensure that there are no lubricant leaks.

63. On which type of engine are electrical heater mats mainly used?. a. Electrical heater mats are mainly used on turboprop engine intakes and propellers. b. Electrical heater mats are mainly used on auxiliary power units. c. Electrical heater mats are mainly used on the pure jet engine intakes.

64. How do inlet acoustic liners reduce engine noise?. a. Inlet acoustic liners reduce engine noise by reflecting sound waves away from the engine. b. Inlet acoustic liners reduce engine noise by absorbing sound waves within the engine nacelle. c. Inlet acoustic liners reduce engine noise by directing soland waves towards the intake and bypass ducts.

65. When it reaches the compressor face, what is the optimum airflow speed in a supersonic intake?. a. The optimum speed of airflow in a supersonic intake at the compressor face is Mach 0.4. b. The optimum speed of airflow in a supersonic intake at the compressor face is Mach 1. c. The optimum speed of airflow in a supersonic intake at the compressor face is Mach 2.

66. What type of intake commonly has a particle separator?. a. A turboprop intake commonly has a particle separator. b. A turbofan intake commonly has a particle separator. c. A turbojet intake commonly has a particle separator.

67. What happens to airflow velocity in an axial flow compressor rotor and stator respectively?. a. Airflow velocity in an axial, flow compressor decreases in the rotor and increases in the stator. b. Airflow velocity in an axial flow compressor increases in the rotor and increases in the stator. c. Airflow velocity in an axial flow compressor increases in the rotor and decreases in the stator.

68. How is the axial velocity of airflow through the axial flow compressor maintained by design?. a. A reducing annulus between the rotor drum and the case maintains the axial velocity of airflow through the axial flow compressor. b. The axial velocity of airflow through the axial flow compressor is maintained by gradually increasing the rotor speed from front to rear. c. The axial velocity of airflow through the axial flow compressor is maintained by adjusting the blade angle to maintain the angle of attack.

69. What controls the variable stator vanes (VSV) and variable inlet air vanes (VIGV) on a full authority digital engine control (FADEC) engine?. a. The VSV and VIGV are controlled by fuel pressure and operated electrically on a FADEC engine. b. The VSV and VIGV are controlled electrically and operated electrically on a FADEC engine. c. The VSV and VIGV are controlled electrically and operated by fuel pressure on a FADEC engine.

70. Which type of compressor can compress to a higher pressure ratios and provide higher air flow for the same frontal area?. a. A centrifugal flow compressor can compress to higher pressure ratios and provide higher air flow for the same frontal area. b. An axial flow compressor can compress to a higher pressure ratios and provide higher air flow for the same frontal area. c. A compound compressor can compress to a higher pressure ratios and provide higher air flow for the same frontal area.

71. What profile is the diffuser of a centrifugal compressor?. a. The diffuser of a centrifugal compressor is divergent. b. The diffuser of a centrifugal compressor is convergent. c. The diffuser of a centrifugal compressor is parallel.

72. How is airflow induced into the centre of the impeller of a centrifugal compressor?. a. Airflow is induced into the centre of the impeller of a centrifugal compressor by using a plenum chamber for reversed airflow. b. Airflow is induced into the centre of the impeller of a centrifugal compressor by using divergent nozzles in the diffuser section. c. Airflow is induced into the centre of the impeller of a centrifugal compressor by providing an initial swirl to the air entering the compressor.

73. What profile of airflow path do stator vanes form?. a. Stator vanes form a parallel airflow path. b. Stator vanes form a divergent al flow path. c. Stator vanes form a convergent airflow path.

74. How many degrees does the gas flow turn in a reverse-flow combustion chamber?. a. In a reverse flow combustion chamber, the gas flow turns 180°. b. In a reverse flow combustion chamber, the gas flow turns 270°. c. In a reverse flow combustion chamber, the gas flow turns 90°.

75. In a combustion chamber, what does the 'toroidal vortex' do?. a. The toroidal vortex stabilizes and anchors the flame and prevents it from moving through the flame tube away from the fuel nozzle area. b. The toroidal vortex cools the flame so it does not cause heat damage to the turbine section. c. The toroidal vortex causes a drop in pressure at the front of the combustion chamber to help draw in fuel.

76. What is the primary advantage of a dual annular combustion (DAC) chamber?. a. The primary advantage of a DAC chamber is better fuel economy. b. The primary advantage of a DAC chamber is reduced harmful emissions. c. The primary advantage of a DAC chamber is that it is quieter in operation.

77. How are the turbine blades of a large gas-turbine engine normally secured to the disc?. a. The turbine blades of a large gas-turbine engine are normally secured to the disc by using a fir tree root with a locking plate. b. The turbine blades of a large gas-turbine engine are normally machined from a solid disc. c. The turbine blades of a large gas-turbine engine are normally secured to the disc by using a dovetail root secured by a pin.

78. Which turbine rotor(s) is/are likely to be shrouded?. a. The high-pressure turbine (HPT) is most likely to be shrouded. b. Either a low-pressure turbine (LPT) or HPT might be shrouded. c. The LPT is most likely to be shrouded.

79. Where is the angle of incidence greater on a typical impulse/reaction turbine blade?. a. At the tip. b. Root and tip equally. c. At the root.

80. What are 3 types of turbine blade profiles?. a. 3 types of turbine blade profiles are bucket, aerofoil and reaction. b. 3 types of turbine blade profiles are impulse, reaction, and impulse/reaction. c. 3 types of turbine blade profiles are impact, aerofoil and impact/reaction.

81. What is the primary advantage of film cooling of turbine components?. a. The primary advantage of film cooling of turbine components is it is less expensive to manufacture than other methods. b. The primary advantage of film cooling of turbine components is it provides a maximum cooling effect with a minimum of cooling. c. The primary advantage of film cooling of turbine components is it is easier to implement than other methods.

82. "What is the purpose of an eductor pipe on an auxiliary power unit (APU) exhaust system?. a. The eductor pipe on an APU exhaust system helps to reduce noise. b. The eductor pipe on an APU exhaust system helps to cool the exhaust. c. The eductor pipe on an APU exhaust system is for thrust augmentation.

83. What produces the greatest noise signature on a high-bypass turbofan engine?. a. The exhaust produces the loudest noise from a high-bypass turbofan engine. b. The fan produces the loudest noise from a high-bypass turbofan engine. c. The compressor produces the loudest noise from a high-bypass turbofan engine.

84. How much thrust is produced by a propeller in a turboprop engine?. a. 90%. b. 10%. c. 60%.

85. Why is a rotorcraft tailpipe normally divergent in shape?. a. A rotorcraft tailpipe normally divergent to improve hover stability. b. A rotorcraft tailpipe normally divergent for noise suppression. c. A rotorcraft tailpipe normally divergent to improve thrust.

86. What is the limitation on the loads on an angular contact bearing?. a. The limitation on the loads on an angular contact bearing is that it can only take thrust loads in one direction. b. The limitation on the loads on an angular contact bearing is that it can only take radial loads. c. The limitation on the loads on an angular contact bearing is that all loads need to be applied at an angle.

87. What is true regarding labyrinth seals used on a gas-turbine engine?. a. Labyrinth seals are used on a gas-turbine engine because they have no friction. However they cannot withstand high temperatures. b. Labyrinth seals are used on a gas-turbine engine because they can withstand high temperatures. However they have higher friction. c. Labyrinth seals are used on a gas-turbine engine because they have no friction and can withstand high temperatures.

88. What are usually the types of main bearings used in gas-turbine engines?. a. The main bearings used in gas-turbine engines are usually plain bearings. b. The main bearings used in gas-turbine engines are usually roller or ball bearings. c. The main bearings used in gas-turbine engines are usually taper roller bearings.

89. What fuel type mixture is Jet B?. a. Jet B is a mixture of 30% kerosene and 70% gasoline. b. Jet B is a mixture of 50/50 mix kerosene and gasoline. c. Jet B is a mixture of 70% kerosene and 30% gasoline.

90. What is a measurable film of oil maintained between moving surfaces called?. a. A measurable film of oil maintained between moving surfaces is called film lubrication. b. A measurable film of oil maintained between moving surfaces is called boundary lubrication. c. A measurable film of oil maintained between moving surfaces is called a splash lubrication.

91. How do you test for water in Fuel?. a. You test for water in fuel by heating it to 200°C and listening for crackles. b. You test for water in fuel by using a hydrokit. c. You test for water in fuel by using litmus paper.

92. What is an HTS oil?. a. An HTS oil has high thermal stability. b. An HTS oil has high-time service. c. An HTS oil is highly temperature sensitive.

93. What is a coupled turboprop engine also known as?. a. A coupled turboprop engine is sometimes called a two-spool engine. b. A coupled turboprop engine is sometimes called an APU. c. A coupled turboprop engine is sometimes called a compounded engine.

94. A turbojet engine delivers 1,000 N of thrust force and moves 500 m. How much work does it do?. a. The turbojet does 0.5 MJ of work. b. The turbojet does 5 kJ of work. c. The turbojet does 0.5 J of work.

95. In a thermodynamic process, what is energy that is unavailable to do work known as?. a. The energy that is unavailable to do work is known as internal energy. b. The energy that is unavailable to do work is known as entropy. c. The energy that is unavailable to do work is known as latent energy.

96. How does pressure relief valve operates in a pressure relief valve system?. a. PRV operates as a regulator valve. b. PRV operates as an over-pressurisation valve. c. The oil pressure varies with the engine RPM.

97. What types of lubrication are used inside gas-turbine engines?. a. Only spray oil lubrication is used inside gas-turbine engines. b. Spray, splash and film oil lubrication are used inside gas-turbine engines. c. Only splash oil lubrication is used inside gas-turbine engines.

98. When is a swash plate pump at the greatest stroke position?. a. A swash plate pump at greatest stroke position at take-off (full power). b. A swash plate pump at greatest stroke position during the approach to landing (idle power). c. A swash plate pump at greatest stroke position in cruise flight.

99. What part of the engine is the EEC programming plug attached to?. a. The EEC programming plug attached to the fan case with a lanyard. b. The EEC programming plug attached to the engine pylon. c. The EEC programming plug attached to the electronic engine control (EEC).

100. How is the engine nacelle normally cooled and ventilated?. a. The engine nacelle is normally cooled and ventilated by atmospheric air through a ram intake. b. The engine nacelle is normally cooled and ventilated by compressor bleed air. c. The engine nacelle is normally cooled and ventilated by an electrical fan.

101. Which type of igniter plugs are usually used in gas-turbine engine-ignition systems?. a. Igniters with low energy and a small electrode gap are usually used. b. Igniters with a heating element, glow type igniter are usually used. c. Igniters with an air gap or semiconductor surface gap are usually used.

102. What type of start start fault does not accelerate the engine during starting?. a. Hung start. b. Wet start. c. Hot start.

103. For what purpose is the electrical connection to an air starter?. a. The electrical connection to an air starter is for the electric motor. b. The electrical connection to an air starter is for the oil temperature sensor. c. The electrical connection to an air starter is for the flyweight cut-out switch.

104. What signals are supplied by the permanent magnet alternator (PMA)?. a. The PMA, which supplies the EEC, may also provide a signal for the LP spool speed. b. The PMA, which supplies the EEC, may also provide a signal for vibration monitoring. c. The PMA, which supplies the EEC, may also provide a signal for the HP spool speed.

105. What colour are alumel thermocouple leads normally?. a. Alumel thermocouple leads are normally coloured green. b. Alumel thermocouple leads are normally coloured white. c. Alumel thermocouple leads are normally coloured red.

106. Which of the following is/are component(s) of a tachogenerator-driven mechanical RPM indicator?. a. A synchronous motor and a drag cup are components of a tachogenerator-driven mechanical RPM Indicator. b. A bourdon tube is a component of a tachogenerator-driven mechanical RPM indicator. c. A synchro position indicator is a component of a tachogenerator-driven mechanical RPM indicator.

107. What is the disadvantage of a geared turbofan engine?. a. A disadvantage of a geared turbofan engine is an increase in weight. b. A disadvantage of a geared turbofan engine is a higher fan tip speed. c. A disadvantage of a geared turbofan engine is a higher fan noise.

108. What position must the propeller be in for engine shut down on a free-turbine engine?. a. On a free-turbine engine, during shutdown, the propeller is allowed to go to the feather position. b. On a free-turbine engine, during shutdown, the propeller is held in a fine-pitch position. c. On a free-turbine engine, during shutdown, the propeller is allowed to stop in any position as it is free to rotate.

109. Which of the following is true of a hydro-mechanical fuel control system?. a. In a hydro-mechanical fuel control system, during flight, the condition lever applies pressure to the propeller control unit (PCU) spring. b. In a hydro-mechanical fuel control system, during flight, the power lever applies pressure to the PCU spring. c. In a hydro-mechanical fuel control system, the constant speed range is controlled by the power lever.

110. What drives the propeller governor and overspeed governor, respectively?. a. The accessory gearbox and reduction gearbox drive the propeller governor and overspeed governor, respectively. b. The reduction gearbox and accessory gearbox drive the propeller governor and overspeed governor, respectively. c. The reduction gearbox and reduction gearbox drive the propeller governor and overspeed governor, respectively.

111. How is an increase in power requirement of a helicopter engine demanded?. a. An increase in the power requirement of a helicopter engine is demanded by a change in the collective control lever. b. An increase in power requirement of a helicopter engine is demanded by a change in the cyclic control stick. c. An increase in power requirement of a helicopter engine is demanded by a change in both the collective control lever and the cyclic control stick.

112. What component allows a helicopter rotor to freewheel?. a. A sprag clutch between the gearbox and rotor head allows a helicopter rotor to freewheel. b. A reduction gear between the drive shaft and rotor head allows a helicopter rotor to freewheel. c. A slipping plate clutch, used in the event of engine failure, allows a helicopter rotor to freewheel.

113. What is the purpose of the surge control valve on an APU?. a. The surge control valve prevents a load compressor surge. b. The surge control valve prevents a power compressor surge. c. The surge control valve provides air supply from the APLI in surge.

114. How does the electronic control box (ECB) monitor the position of the air intake flap actuator?. a. The ECB monitors the position of the air intake flap actuator by the use of two limit switches and an actuator. b. The ECB monitors the position of the air intake flap actuator by the use of two limit switches and two position switches. c. The ECB monitors the position of the air intake flap actuator by the use of an actuator and two position switches.

115. What is the disadvantage of using liners for reducing noise?. a. The disadvantage of using liners for reducing noise is the addition of weight and increase in specific fuel consumption. b. The disadvantage of using liners for reducing noise is the increase in specific fuel consumption and higher aerodynamic drag. c. The disadvantage of using liners for reducing noise is the increase in weight and decrease in specific fuel consumption.

116. Which engine mounting system normally requires a torque compensator?. a. A torque compensator is normally required on the mounting system of a turboprop engine. b. A torque compensator is normally required on the mounting system of a turbofan engine. c. A torque compensator is normally required on the mounting system of a pure turbojet engine.

117. What is propulsive efficiency?. a. Propulsive efficiency is the ability of the engine to drive the aircraft in flight. b. Propulsive efficiency is the engine efficiency measured on the ground. c. Propulsive efficiency is the engine efficiency measured when stationary on the ground.

118. How does the specific fuel consumption of a twin-spool low-bypass engine compare with that of a turbojet?. a. The specific fuel consumption of a twin-spool low-bypass engine is better than that of a turbojet. b. The specific fuel consumption of a twin-spool low-bypass engine is worse than that of a turbojet. c. The specific fuel consumption of a twin-spool low-bypass engine is the same as that of a turbojet.

119. What does a thrust flat-rated engine deliver (at a fixed throttle lever position)?. a. A thrust flat-rated engine delivers a fixed thrust below the flat-rated temperature. b. A thrust flat-rated engine delivers a fixed engine speed below the flat-rated temperature. c. A thrust flat-rated engine delivers a fixed thrust above the flat-rated temperature.

120. What is the purpose of a heater in a thermocouple-type fire sensor system?. a. A heater in a thermocouple-type fire sensor system is to form the hot junction. b. A heater in a thermocouple-type fire sensor system is for system test. c. A heater in a thermocouple-type fire sensor system is to prevent icing.

121. When should an oil sample be taken?. a. An oil sample should be taken after the engine has been running for a long period. b. An oil sample should be taken within 15 minutes of the engine shut down. c. An oil sample should be taken when the oil system is cold.

122. Why should you ensure a pneumatic power source is available before the engine shuts down?. a. You ensure that a pneumatic power source is available before the engine shuts down to clear an internal engine fire/tailpipe fire. b. You ensure that a pneumatic power source is available before the engine shuts down to ventilate the engine in case of a high EGT. c. You ensure that a pneumatic power source is available before the engine shuts down to clear fuel from the combustion chamber after shutdown.

123. What type of detergent is typically used for fluid cleaning?. a. Emulsion type detergent is typically used for fluid cleaning. b. Abrasive type detergent is typically used for fluid cleaning. c. Acidic type detergent is typically used for fluid cleaning.

124. What is the primary purpose of an on-condition maintenance program?. a. The primary purpose of an on-condition maintenance program is to replace components at specific periods. b. The primary purpose of an on-condition maintenance program is to Inspect and test components periodically. c. The primary purpose of an on-condition maintenance program is to predict when components will fail.

125. What part of an engine is 'ferrography' used to examine?. a. Ferrography is used to examine combustion chambers. b. Ferrography is used to examine turbine blades. c. Ferrography is used to examine engine oil.

126. What does a fuel system in long-term storage need?. a. A fuel system in long-term storage is inhibited with an approved inhibiting oil. b. A fuel system in long-term storage is inhibited with the normal operating fuel. c. A fuel system in long-term storage does not need to be inhibited.

127. How long can an installed engine be stored without any maintenance action other than fitting covers and blanks to the Intake?. a. For 7 days without any maintenance. b. For 30 days without any maintenance. c. For 12 months without any maintenance.

128. What should an engine be inspected for, after three years of storage in an envelope?. a. The engine should be inspected for oil leaks and humidity. b. The engine should be inspected for corrosion and oil leaks. c. The engine should be inspected for corrosion.

129. What is the purpose of the air intake?. a. The purpose of the air intake is to reduce the drag on the front of the engine. b. The purpose of the air intake is to provide air to the compressor under the optimum conditions. c. The purpose of the air intake is for cosmetic reasons and has no real purpose.

130. Which type of aircraft commonly uses bell-mouth air inlets?. a. Only high-speed aeroplanes commonly use bell-mouth air inlets. b. Low-speed aircraft and turboshaft helicopters commonly use bell-mouth air inlets. c. Only turboshaft helicopters commonly use bell-mouth air inlets.

131. What happens to the airflow approaching the inlet when total ram recovery is achieved?. a. When total ram recovery is achieved, the airflow approaching the inlet slows down due to increased pressure. b. When total ram recovery is achieved, the airflow approaching the inlet accelerates over the outside of the inlet duct. c. When total ram recovery is achieved, the airflow approaching the inlet causes a drop in pressure.

132. At low compressor speeds, what is the position of the variable stator vanes (VSV)?. a. At low compressor speeds, the position of the variable stator vanes (VSV) is partially closed. b. At low compressor speeds, the position of the variable stator vanes (VSV) is fully closed. c. At low compressor speeds, the position of the variable stator vanes (VSV) is fully open.

133. By what is the compression in a centrifugal compressor provided?. a. The compression in a centrifugal compressor is only provided by the impeller. No compression takes place in the diffuser. b. The compression in a centrifugal compressor is provided by the impeller and also by the diffuser. c. The compression in a centrifugal compressor is only provided by the diffuser. No compression takes place in the impeller.

134. What is a design feature of an axial-flow compressor rotor blade?. a. An axial-flow compressor rotor blade has a greater stagger angle at the root than at the tip. b. An axial-flow compressor rotor blade has a lower stagger angle at the root than at the tip. c. An axial-flow compressor rotor blade has a constant stagger angle from root to tip.

135. What maximises the efficiency of a centrifugal compressor?. a. A small clearance is required between the impeller and shroud to maximise the efficiency of a centrifugal compressor. b. The Impeller must turn as fast as possible to maximise the efficiency of a centrifugal compressor. c. A large clearance is required between the impeller and shroud to maximise the efficiency of a centrifugal compressor.

136. What is meant by a combustion section mixture ratio of 15:1?. a. A mixture ratio of 15:1 is 15 parts air to 1 part fuel. b. A mixture ratio of 15:1 is 1 part air to 15 parts fuel. c. A mixture ratio of 15:1 is 15 parts oxygen to 1 part fuel.

137. Secondary air in the combustion section is what percentage of the total air delivered?. a. Secondary air in the combustion section is 20% of the total air delivered. b. Secondary air in the combustion section is 80% of the total air delivered. c. Secondary air in the combustion section is 8% of the total air delivered.

138. What type of turbine does a modern gas turbine engine use?. a. A modern turbojet engine uses an impulse/reaction turbine. b. A modern turbojet engine uses a pure impulse turbine. c. A modern turbojet engine uses a pure reaction turbine.

139. In a pure reaction turbine, what force drives the rotation of the turbine blades?. a. In a pure reaction turbine, the reaction from the deceleration of the gas flow drives the rotation of the turbine blades. b. In a pure reaction turbine, drag forces created by the gas flow deflection drive the rotation of the turbine blades. c. In a pure reaction turbine, the reaction to the acceleration of gases between the turbine blades drives the rotation of the turbine blades.

140. What is the relationship between the efficiency of a turbine blade and its rotational speed?. a. The relationship between the efficiency of a turbine blade and its rotational speed is the efficiency remains constant regardless of the rotational speed. b. The relationship between the efficiency of a turbine blade and its rotational speed is the efficiency is inversely proportional to the rotational speed. c. The relationship between the efficiency of a turbine blade and its rotational speed is the efficiency increases as the rotational speed increases.

141. What are the chronological stages of turbine blade creep?. a. The chronological stages of turbine blade creep are: primary-secondary - failure. b. The chronological stages of turbine blade creep are: primary-secondary - elementary. c. The chronological stages of turbine blade creep are: primary-secondary - tertiary.

142. What is the advantage of turbine blades with a directional solidified structure?. a. The advantage of turbine blades with a directional solidified structure is they are more creep-resistant. b. The advantage of turbine blades with a directional solidified structure is they are easier to manufacture. c. The advantage of turbine blades with a directional solidified structure is they are more resistant to corrosion.

143. What is the maximum flow velocity through a convergent nozzle?. a. The maximum flow velocity through a convergent nozzle is Mach 1. b. The maximum flow velocity through a convergent nozzle is Mach 0.7. c. The maximum flow velocity through a convergent nozzle is above Mach 1.

144. What does an exhaust pressure ratio of 2:1 represent?. a. An exhaust pressure ratio of 2:1 represents turbine exit pressure twice that of nozzle exit pressure. b. An exhaust pressure ratio of 2:1 represents nozzle exit pressure twice that of the turbine exit pressure. c. An exhaust pressure ratio of 2:1 represents compressor discharge pressure is twice that of the exhaust pressure.

145. What does a pressure balance chamber used on some engines do?. a. A pressure balance chamber creates additional scavenge pressure for the oil system. b. A pressure balance chamber ensures that lubrication oil remains inside the bearing housing. c. A pressure balance chamber opposes the forward thrust created by the compressor and offloads the compressor thrust bearing.

146. How much more radial load can a roller bearing take compared to a ball bearing?. a. Compared to a ball bearing, a roller bearing can take approximately 60% more radial load. b. Compared to a ball bearing, a roller bearing can take approximately 100% more radial load. c. Compared to a ball bearing, a roller bearing can take approximately 20% more radial load.

147. What is the operating principle of a carbon seal?. a. A carbon seal has positive contact with a polished surface. b. A carbon seal has positive airflow over a polished surface. c. A carbon seal has oil pressure on both sides.

148. What is meant by the flashpoint of an oil?. a. The flashpoint of an oil is the lowest temperature it can form an ignitable mixture. b. The flashpoint of an oil is the highest temperature it can form an ignitable mixture. c. The flashpoint of an oil is the temperature at which the oil spontaneously ignites.

149. What is Prist?. a. Prist is an icing inhibitor for fuel. b. Prist is an anti-fungal additive for fuel. c. Prist is an oil anti-oxidant.

150. What is the chemical name for microbiological growths in Jet fuel?. a. Cladosporium Resinae is a microbiological growth in jet fuel. b. Staphylococcus aureus is a microbiological growth in jet fuel. c. Clostridium botulinum is a microbiological growth in Jet fuel.