GAS TURBIN – Air – DGCA Question Bank For Politics

#1. Where does the air expand in an impulse turbine?

Rotors.

Stators.

Rotors and stators.

It does not expand.

#2. The turbine blades in gas turbine engines?

Are mainly impulse-type at the tips and mainly reaction-type at the roots.

Are mainly impulse-type at the roots and reaction -type at the tips.

Are mainly impulse-type at all points.

Are mainly reaction-type at all points.

#3. When air is bled from the compressor of a gas turbine engine?

EGT & EPR both decrease.

EGT & EPR both increase.

EGT decreases and EPR increases.

EGT increases and EPR decreases.

#4. The correct sequence of a turbo-jet?

Induction, compression, power, exhaust.

Induction, compression, expansion, exhaust.

Induction, depression, combustion, power, exhaust.

Induction, compression, combustion, expansion, power/exhaust.

#5. Where does pressure increase in an axial flow compressor?

Rotors.

Stators.

Rotors and stators.

The diffusers.

#6. Where does velocity increase in an axial flow compressor?

Rotors.

Stators.

Rotors and stators.

The diffusers.

#7. The rocking motion exhibited by the rotor blades of stationary gasturbine engines?

Is to reduce centrifugal stresses when running.

Is to reduce vibration when running.

Is prevented by centrifugal force when running.

Is a sign of blade root wear.

#8. An APU?

Provides only AC power.

Provides AC power and bleed air.

Is a constant speed device.

Provides AC power, bleed air, and in some cases hydraulkpower.

#9. EPR is the ratio of?

Po:P5.

LP compressor inlet pressure : LP turbine outlet pressure.

LP turbine outlet pressure : LP compressor inlet pressure.

HP compressor outlet pressure to LP turbine inlet pressure.

#10. EGT is measured at the?

LP turbine inlet.

LP turbine outlet.

HP turbine inlet.

HP turbine outlet.

#11. TIT is measured at the?

Combustion chamber inlet.

Compressor outlet.

Upstream of the turbine.

Downstream of the turbine.

#12. As air passes through the impeller of a centrifugal compressor, its velocity ..........., its temperature ........, and its pressure.......... ?

Increases, increases, Increases.

Increases, increases, decreases.

Increases, decreases, decreases.

Decreases, decreases, decreases.

#13. As air passes through the diffuser ring of a centrifugal compressor, its velocity............., its temperature.........., and its pressure...........?

Decreases, increases, increases.

Increases, increases, decreases.

Increases, decreases, decreases.

Decreases, decreases, decreases.

#14. As air passes through the rotors of an axial flow compressor, its velocity ........, its temperature............, and its pressure........?

Increases , increases, increases.

Increases , increases, decreases.

Increases , decreases, decreases.

Decreases , decreases, decreases.

#15. As air passes through the stators of an axial flow compressor, its velocity ............, its temperature .........., and its pressure...........?

Decreases , increases, increases.

Increases , increases, decreases.

Increases , decreases, decreases.

Decreases , decreases, decreases.

#16. The air enters a centrifugal compressor impeller at its ........., then............, before leaving .............. through the diffuser?

Throat, expanding radially, axially.

Eye, accelerating radially, tangentially.

Eye, decelerating radially, radially.

Throat, expanding axially, axially.

#17. Opening bleed valves?

Increase EGT and decreases power.

Increase EGT and power.

Decrease EGT and increase power.

Decrease EGT and power.

#18. An illuminated reverse thrust light means?

The engine is producing reverse thrust.

The thrust reverse system is in the reverse thrust position and will produce reverse thrust when the engine is accelerated.

The thrust reverse system is unlocked.

The thrust reverse system is locked.

#19. Torque in a turboprop engine a hydraulic-type torque meter measures torque at the?

Free power turbine shaft.

Reduction gearbox.

Propeller shaft.

Engine mounting feet.

#20. An APU automatic shutdown system is sensitive to? 1.High RPM. 2.Low oil pressure. 3.High oil temperature. 4.High EGT. 5.Vibration. 6.Fire. 7.EPR.

All of the above

1, 2, 3, 4, 6.

1, 2, 3, 5, 6.

2, 3, 4, 5, 7.

#21. The most probable cause of a hung start is?

Defective igniters.

Throttle too far open.

Pool of fuel in the exhaust pipe.

Starter disengaging too soon.

#22. Power output in a turbojet is set using?

EGT.

EPR.

Torque.

Fuel flow.

#23. Power output in a turboprop is set using?

EGT

EPR.

Torque.

Fuel flow.

#24. In an impulse root-type turbine the air expands.

Stators.

Rotors.

Both rotors and stators to the same degree.

Both stator and rotors but not to the same degree.

#25. Anti-surge bleed valves?

Provide bleed air to the packs, without causing surge.

Provide bleed air to the packs but might cause surge.

Dump air overboard to avoid compressor surge.

Dump air overboard to avoid turbine surge.

#26. Power output in a turbofan is set using?

EGT.

EPR.

N3.

Fuel flow.

#27. In a high bypass turbofan the hot and cold airflows mix?

In the combustion chamber.

In the turbines.

In the bypass duct.

Downstream of the turbines.

#28. A hung start occurs?

Below self-sustaining RPM.

At ground idle.

Below ground idle.

Above ground idle.

#29. The sequence of blades in a gas turbine compressor is?

Rotor stator.

Stator rotor.

Stator stator rotor.

Rotor rotor stator.

#30. What happens to the pressure of the air as it passes through a jet engine turbine.

Increase, Decrease.

Increase, increase.

Decrease decrease.

Decrease, increase.

#31. What happens to the temperature of the air as it passes through a single stage jet engine turbine.

Increase decrease

Increase increase.

Decrease decrease.

#32. What happens to the velocity of the air as it passes through a single stage jet engine turbine.

Increase decrease.

Decrease increase.

No change decrease.

No change increase.

#33. If the EPR air intake sensor becomes blocked the gauge will?

Over indicate.

Under indicate.

Indicate zero.

Indicate normally.

#34. As a jet aircraft accelerates along the runway during the take-off run its EPR?

Increases.

Decreases.

Remains constant.

Decreases then increases.

#35. Where is the highest temperature in a jet engine?

Compressor outlet.

Combustion chamber.

Turbine inlet.

Turbine outlet.

#36. Where is the highest static pressure in a jet engine?

Diffuser outlet.

Combustion chamber.

Turbine inlet.

Turbine outlet.

#37. What happens to air pressure velocity and temperature as it passes through an axial flow compressor?

Increase Increase Increase

Decrease Decrease Increase

Increase constant Increase

Increase constant decrease.

#38. The thrust reverse light illuminates when?

Reverse thrust is selected.

Reverse thrust is being produced.

Reverse thrust system is unlocked.

Reverse thrust comes on in flight.

#39. In a modern aircraft the reverse thrust system condition is indicated on?

EFIS PFD.

EFIS ND.

EICAS or ECAM.

Reverse thrust control panel.

#40. EPR is the ratio of?

LP compressor outlet pressure to LP turbine outlet pressure.

HP compressor outlet pressure to LP turbine outlet pressure.

LP turbine outlet pressure to LP compressor inlet pressure.

HP turbine outlet pressure to HP compressor inlet pressure.

#41. . In an impulse - type turbine the air expands?

At the roots.

At the tips.

In the stator.

In the rotor.

#42. In an reaction - type turbine the air expands?

At the roots.

At the tips.

In the stator.

In the rotor.

#43. In an impulse / reaction-type turbine the air expands?

At the roots.

In the rotor.

In the stator.

In both the stator and the rotor.

#44. At the outlet of the stators of an impulse/reaction-type turbine the air velocity is?

Greatest at the roots.

Greatest at the tips.

Common along the blade length.

Lower than at the inlet to the stator.

#45. The sequence in a turbine is?

Rotor stator.

Stator rotor.

Rotor rotor stator.

Stator stator rotor.

#46. VIG Vs?

Prevent stall by increasing air velocity.

Prevent surge by decreasing mass flow.

Prevent stall by controlling angle of attack.

Prevent stall and surge by controlling angle of attack and mass flow.

#47. A free power turbine?

Extracts energy that would otherwise be wasted in the exhaust gasses.

Drives only the LP compressor or fan.

Drives only the HP compressor.

Does not drive any of the compressors or fan.

#48. If the engines are heard to emit a ticking or rattling noise prior to start up on a windy day?

Do not start the engines, because they are defective.

This is normal because the compressor blade roots are a loose fit.

It indicates wear of the blade roots but is unlikely to be a problem.

It indicates bird strike or foreign object damage.

#49. Compressor blade length?

Is greatest at the outlet end of the compressor.

Is greatest at the inlet end of the compressor.

Is constant.

Is greatest in the HP compressor.+

#50. Turbine cooling air is drawn from?

The air intake.

The compressors.

The jet pipe.

The bypass duct.

#51. VIGVs are ......... and anti-surge bleed valves are ............ ?

Open at low RPM, open at low RPM.

Open at low RPM, closed at low RPM.

Closed at low RPM, closed at low RPM.

Closed at low RPM, open at low RPM.

#52. The APU is usually started using?

Main DC bus bar power.

Battery power.

External power.

Main AC bus bar power.

#53. The HP fuel pump in a jet engine ?

Provides fuel under sufficient pressure to ensure that it is atomised by the burners.

Ensure the correct fuel air ratio.

Is a minimum swash plate angle prior to engine start up.

Is usually of the constant delivery type.

#54. Jet engines are normally shut down by?

The FADEC system.

Closing the HP cock.

Closing the throttle and switching off the ignition.

Closing the LP cock.

#55. Jet engines employ a constant?

Temperature combustion process.

Volume combustion process.

Pressure combustion process.

Mass flow combustion process.

#56. Oil becomes aerated in jet engines because?

The oil pressure in the bearings is very high.

RPM is very high.

The bearings are pressurised with compressor bleed air.

The gears break up the oil into fine droplets which trap air.

#57. The main source of high frequency jet engine noise is the?

Fan blades.

HP compressor blades.

Turbines

Exhaust plume.

#58. The most efficient engine type for flight below 350 Kts is?

Low bypass Turbofan.

Turbojet.

High bypass turbofan.

Turboprop.

#59. Bleeding air from a jet engine?

Increase EGT, EPR and thrust.

Increases EGT but decreases EPR and thrust.

Decrease EGT, EPR and thrust.

Decrease EGT and EPR, but increases thrust.

#60. The terms used for temperatures in jet engines include? Upstream of HP turbine Downstream of LP turbine In the jet pipe

PTIT JPT LPT.

TIT LPT JPT.

TIT EGT JPT.

T1 TIT EGT.

#61. A single stage centrifugal compressor is?

Lighter and smaller than an equivalent axial flow type.

An impeller followed by a diffuser.

A diffuser followed by an impeller.

Made from stainless steel.

#62. Sub sonic aircraft jet engine air intakes are usually?

Variable area.

Convergent.

Divergent.

Bell mouth type.

#63. As a jet aircraft accelerates during the take-off run its EPR?

Increases.

Decreases,

Remains constant.

Increases then decreases.

#64. The highest gas pressure in a jet engine is?

In the turbine Inlet area.

In the turbine outlet area.

In the compressor inlet.

In the combustion chamber inlet.

#65. Increasing fuel flow will?

Increase SFC, thrust and N1.

Increase thrust and N1 but decrease SFC.

Increase thrust and N1 but might increase or decrease SFC.

Increase thrust and N1 but does not affect SFC.

#66. The SFC of a jet engine is lowest at?

Start up.

Maximum RPM.

High RPM and high altitude.

High RPM and low altitude.

#67. Compressor stall can be minimised by using?

Axial flow compressors, bleed valves and VIGVs.

VIGVs, bleed valves and acceleration control units.

Two stage turbines, and convergent - divergent propelling nozzles.

All of the above.

#68. In a pure turbojet almost?

20% of the air goes through the combustion chamber.

50% of the air goes through the combustion chamber.

75% of the air goes through the combustion chamber.

100% of the air that goes through the combustion chamber.

#69. The engine core in a modern turbofan engine?

Is very large compared to a turbojet.

Is very small compared to a turbojet.

Handles all of the airflow.

Is the cold section.

#70. In a modern turbofan engine?

The free power turbine drives the fan.

The HP turbine drives the fan.

The largest turbine drives the fan.

The front turbine drives the fan.

#71. . Bleed valves?

Prevent stall by reducing airflow into the compressor.

Prevent stall by reducing airflow out of the compressor.

Prevent stall by increasing mass flow through the compressor.

Prevent stall by reducing mass flow through the rear of the compressor.

#72. VIGVs?

Prevent stall by increasing mass flow through the compressor at high RPM.

Prevent stall by reducing mass flow through the compressor at low RPM and ensuing that the air strikes the first stage rotors at an acceptable angle of attack at all RPMs.

Prevent stall by increasing mass flow through the compressor at low RPM and ensuing that the air strikes the first stage rotors at an acceptable angle of attack at all RPMs.

Bleeding air away from the compressor at low RPM.

#73. EPR is the ratio of?

Compressor outlet pressure to compressor inlet pressure.

Compressor inlet pressure to compressor outlet pressure.

Turbine outlet pressure to compressor inlet pressure.

Turbine inlet pressure to compressor outlet pressure.

#74. The engine illustrated is a?

Turboprop.

Turbofan.

Twin spool.

Tripple spool.

#75. The engine illustrated is a?

Turboprop

Turbofan.

Twin spool.

Tripple spool.

#76. What proportion of the thrust is produced by the fan in a modern high bypass turnbofan?

None of it.

100% of it.

The majority of it.

A small proportion of it.

#77. Illumination of the thrust reverse light indicates?

Reverse thrust mode is active.

Reverse thrust mode has been selected but is not yet active.

Reverse thrust system mechanism is unlocked.

Reverse thrust system is armed and awaiting touch down.

#78. The reverse thrust system in a modern high bypass turbofan?

Reverses both hot and cold streams.

Reverses only the hot stream.

Reverses only the cold stream but also blocks the hot stream.

Reverses only the cold stream leaving the hot stream unaffected.

#79. A hung start is most likely to be caused by?

Defective igniter plugs.

Defective acceleration control unit.

Excessive throttle opening rate.

Flat battery or defective starter motor.

#80. If a jet engine does not light up during the start cycle?

Shut down and try again, but not more than three times.

Shut down, wait until the starter cools down then try again.

Close the HP cock, but keep the starter running to blow out the fuel. Allow the starter to cool down then try again.

Close the LP cock and keep the starter motor running to blow out the fuel. Allow the starter to cool down then try again.

#81. If the ground crew report a fire in the jet pipe during start up?

No action is required because this simply means that the engine has started.

Close the Lp cock and starter motor immediately.

Close the HP cock but keep the starter running to cool the turbines.

Close both the HP and LP cocks a discharge the fire bottles.

#82. During a jet engine start cycle?

EGT peaks just after ground idle.

EGT peaks just before ground idle.

EGT peaks just before SSRPM.

EGT peaks just after light up.

#83. Modern jet engine fuel systems?

Employ variable delivery HP pumps that do not require lubrication flow.

Employ variable delivery HP pumps that require a lubricating flow.

Employ constant delivery HP pumps that do not require a lubricating flow.

Employ constant delivery HP pumps that require a lubricating flow.

#84. A swash plate type HP fuel pump is used in?

The airframe fuel systems of modern aircraft.

Constant pressure systems.

Constant flow systems.

Constant volume systems.

#85. A free power turbine ?

Drives the fan through a free wheel unit.

Is the first in a multiple turbine system.

Is the last in a multiple turbine system and does not drive any of the spools.

Is the last in a multiple turbine system and drives the LP spool.

#86. By-pass ratio is?

Secondary airflow divided by primary airflow.

Primary airflow divided by secondary airflow.

Cold stream flow divided by hot stream flow.

Hot stream flow divided by cold stream flow.

#87. The length of the blades in an axial flow compressor?

Decreases with increasing RPM.

Decreases from rear to front.

Increases from front to rear.

Decreases from front to rear.

#88. LP spool blades are normally?

Hotter than HP spool blades.

Larger than HP spool blades.

Faster than HP spool blades.

More highly loaded than HP spool blades.

#89. In the combustion section of a jet engine?

Air, temperature, pressure and velocity all increase.

Air temperature increases but pressure and velocity decrease.

Air temperature and velocity increase but pressure decreases.

Air temperature, pressure and velocity all decrease.

#90. Jet engine igniter systems are energised? 1. For starting. 2. For in flight relighting. 3. In heavy rain. 4. When taking-off and landing. 5. At high angles of attack.

All of the above.

1, 2, 3, 4.

2, 3, 4, 5.

1, 3, 4, 5.

#91. Which of the curves in the diagram Best represents the performance of a high bypass turbofan?

A

B

C

D

#92. A twin spool engine is?

Lighter than its single spool equivalent

Heavier than its single spool equivalent.

More prone to stall and surge.

Less prone to stall and surge.

#93. The starter motor of a multy - spool turbine engine?

Drive the LP spool.

Drives the IP spool.

Drives all of the spools.

Drives the HP spool.

#94. The term gas generator refers to the?

Fan.

Compressors.

Compressors, combustion section and the coupled turbines in a free power turbine engine.

The HP spool in a three spool turbofan.

#95. Jet engine compression ratio is?

IP turbine outlet pressure divided by LP compressor inlet pressure.

HP turbine outlet pressure divided by HP compressor inlet pressure.

Compressor outlet pressure divided by compressor inlet pressure.

Compressor outlet pressure divided by ambient pressure.

#96. Secondary airflow in a bypass engine?

Is the cold stream flow.

Is the bypass flow.

Is the flow within the primary combustion zone.

Is within the combustion chamber but not within the primary combustion zone.

#97. The stator blades of a turbine are?

In front of the rotors and called nozzle guide vanes.

In front of the rotors and called the inlet guide vanes.

Behind the rotors and called the diffusers.

Behind the rotors and of longer span.

#98. Jet SFC is?

Greatest at high RPM at high altitude.

Least at high altitude at high RPM.

Greatest at low altitude at high RPM.

Greatest at high altitude at low RPM.

#99. The component illustrated is the impeller of a ?

Single entry single stage centrifugal compressor.

Double entry single stage centrifugal compressor.

Single entry two stage centrifugal compressor.

Double entry two stage centrifugal compressor.

#100. Jet pipe temperature is usually measured by?

A single thermocouple.

A number of thermocouples connected in series.

A number of thermocouples connected in parallel.

A resistive probe or probes.

#101. Causes of compressor stall and surge include? 1. Excessive throttle opening rates. 2. Excessive throttle closing rates. 3.Gas winds and manoeuvring. 4. High angles of attack. 5.Tubulence. 6. I deg of intakes. 7. Compressor wear or damage.

1, 3, 4, 5, 6, 7.

1, 2, 4, 5, 6, 7.

2, 3, 4, 5, 6, 7.

All of the above

Dgca Question Bank For Pilots

Results

#1. Where does the air expand in an impulse turbine?

#2. The turbine blades in gas turbine engines?

#3. When air is bled from the compressor of a gas turbine engine?

#4. The correct sequence of a turbo-jet?

#5. Where does pressure increase in an axial flow compressor?

#6. Where does velocity increase in an axial flow compressor?

#7. The rocking motion exhibited by the rotor blades of stationary gasturbine engines?

#8. An APU?

#9. EPR is the ratio of?

#10. EGT is measured at the?

#11. TIT is measured at the?

#12. As air passes through the impeller of a centrifugal compressor, its velocity ..........., its temperature ........, and its pressure.......... ?

#13. As air passes through the diffuser ring of a centrifugal compressor, its velocity............., its temperature.........., and its pressure...........?

#14. As air passes through the rotors of an axial flow compressor, its velocity ........, its temperature............, and its pressure........?

#15. As air passes through the stators of an axial flow compressor, its velocity ............, its temperature .........., and its pressure...........?

#16. The air enters a centrifugal compressor impeller at its ........., then............, before leaving .............. through the diffuser?

#17. Opening bleed valves?

#18. An illuminated reverse thrust light means?

#19. Torque in a turboprop engine a hydraulic-type torque meter measures torque at the?

#20. An APU automatic shutdown system is sensitive to? 1.High RPM. 2.Low oil pressure. 3.High oil temperature. 4.High EGT. 5.Vibration. 6.Fire. 7.EPR.

#21. The most probable cause of a hung start is?

#22. Power output in a turbojet is set using?

#23. Power output in a turboprop is set using?

#24. In an impulse root-type turbine the air expands.

#25. Anti-surge bleed valves?

#26. Power output in a turbofan is set using?

#27. In a high bypass turbofan the hot and cold airflows mix?

#28. A hung start occurs?

#29. The sequence of blades in a gas turbine compressor is?

#30. What happens to the pressure of the air as it passes through a jet engine turbine.

#31. What happens to the temperature of the air as it passes through a single stage jet engine turbine.

#32. What happens to the velocity of the air as it passes through a single stage jet engine turbine.

#33. If the EPR air intake sensor becomes blocked the gauge will?

#34. As a jet aircraft accelerates along the runway during the take-off run its EPR?

#35. Where is the highest temperature in a jet engine?

#36. Where is the highest static pressure in a jet engine?

#37. What happens to air pressure velocity and temperature as it passes through an axial flow compressor?

#38. The thrust reverse light illuminates when?

#39. In a modern aircraft the reverse thrust system condition is indicated on?

#40. EPR is the ratio of?

#41. . In an impulse - type turbine the air expands?

#42. In an reaction - type turbine the air expands?

#43. In an impulse / reaction-type turbine the air expands?

#44. At the outlet of the stators of an impulse/reaction-type turbine the air velocity is?

#45. The sequence in a turbine is?

#46. VIG Vs?

#47. A free power turbine?

#48. If the engines are heard to emit a ticking or rattling noise prior to start up on a windy day?

#49. Compressor blade length?

#50. Turbine cooling air is drawn from?

#51. VIGVs are ......... and anti-surge bleed valves are ............ ?

#52. The APU is usually started using?

#53. The HP fuel pump in a jet engine ?

#54. Jet engines are normally shut down by?

#55. Jet engines employ a constant?

#56. Oil becomes aerated in jet engines because?

#57. The main source of high frequency jet engine noise is the?

#58. The most efficient engine type for flight below 350 Kts is?

#59. Bleeding air from a jet engine?

#60. The terms used for temperatures in jet engines include? Upstream of HP turbine Downstream of LP turbine In the jet pipe

#61. A single stage centrifugal compressor is?

#62. Sub sonic aircraft jet engine air intakes are usually?

#63. As a jet aircraft accelerates during the take-off run its EPR?

#64. The highest gas pressure in a jet engine is?

#65. Increasing fuel flow will?

#66. The SFC of a jet engine is lowest at?

#67. Compressor stall can be minimised by using?

#68. In a pure turbojet almost?

#69. The engine core in a modern turbofan engine?

#70. In a modern turbofan engine?

#71. . Bleed valves?

#72. VIGVs?

#73. EPR is the ratio of?

#74. The engine illustrated is a?

#75. The engine illustrated is a?

#76. What proportion of the thrust is produced by the fan in a modern high bypass turnbofan?

#77. Illumination of the thrust reverse light indicates?

#78. The reverse thrust system in a modern high bypass turbofan?