DGCA Module 15 Gas Turbine Engine from 1st Session 2021 paper includes technical questions on jet engine components, thermodynamics, performance, and troubleshooting. It tests conceptual understanding, practical knowledge, and application in real aircraft maintenance scenarios.
Module 15
1st Session of 2021
1. Power, torque and work formula requires __________ to start.
A) Velocity
B) Time
C) Force
D) Acceleration
2. Work is force x distance, what additional thing is required in the formula is power.
A) Speed
B) Time
C) Velocity
3. Mass x velocity is a consideration for.
A) Stationary object
B) Moving object
4. Turboshaft aircraft use what type of exhaust hose.
A) Convergent
B) Divergent
C) Convergent-divergent
5. The installed engine should be re-preserved after.
A) 3 weeks
B) 6 months
C) 1 month
D) 7 days
6. Thermal efficiency and propulsive efficiency depends on.
A) Size of compressor
B) Size of turbine
C) Weight and diameter of engine for a given output
D) All of the above
7. On dual spool fan is connected to.
A) LP shaft
B) HP shaft
C) External free turbine
8. Volume of air passing through the engine depends on.
A) Compressor speed (RPM)
B) Forward speed of the aircraft
C) Density of ambient air
D) All of the above
9. An inlet on the side of the fuselage, powerplant pod.
A) Flush
B) Scoop
C) Wing
10. Type of inlet in which the pilot sits low in the fuselage and close to the nose.
A) Subsonic
B) Supersonic
C) Split entrance
D) Both A and B
11. The compressor manifold diverts the air flow from the diffuser into the combustion chambers. The air outlet is formed as a duct called.
A) Air outlet duct
B) Air inlet duct
C) Combustion chamber intake duct
12. Which compressor has resistance to FOD.
A) Centrifugal flow
B) Axial flow
C) Axial – centrifugal flow
13. MTCS.
A) Centrifugal flow compressor is suitable for small engines
B) Axial flow compressor is used only in piston engines
C) Centrifugal compressors are used in rockets
14. Steps to obtain max compressor blade efficiency and airflow is controlled by.
A) IGV
B) Rotor of compressor
C) Stator of compressor
15. The amount of thrust depends on
A) Mass of air passed through it
B) Air passing past it
16. Large area of outer liner in can type combustion chamber surrounds the liner on.
A) Front end
B) Exit end
C) Middle area
17. A can type combustion chamber must have some means of spreading the combustion during the initial starting operation. This is accomplished by.
A) Inter-connecting tubes
B) Liner
C) Tube
18. Inter-connecting tubes are used for.
A) To cool the turbine blades
B) To spread the combustion during the initial starting operation
C) To reduce compressor pressure ratio
19. MTCS for centrifugal flow compressor.
A) Diffuser is used to convert maximum K.E to P.E.
A) Diffuser is used to convert maximum P.E to K.E.
20. Which type of blade where adiabatic velocity and pressure drops throughout the blade length.
A) Impulse type
B) Reaction type
C) Impulse-reaction type
D) Impulse-reaction action type
21. MTCS for turbine blade.
A) Turbine blade is the result of centrifugal loads
B) Turbine disc is the result of thermal stresses
C) A series of grooves or notches are manufactured in the rims of the disc for blade root design
D) All of the above
22. Where is any stress crack or distortion found on the leading edge of first stage turbine blade.
A) Over speed
B) Over temperature may be suspected
C) Over Velocity
23. Blade creep (creep) is caused in turbine blades by.
A) Excessive centrifugal load and over temperature
B) Centripetal force and over temperature
C) Over speed
24. What is included in the exhaust cone assembly.
A) Outer tube, inner cone and tail pipe
B) Exhaust tube, tailpipe and jet nozzle
C) Outer tube, inner cone and hollow radial strut or tie rod
25. Function of exhaust section is.
A) Increase pressure of exhaust gases
B) Provide final or exhaust velocity
C) Both A and B
26. In supersonic aircraft jet nozzle design.
A) Convergent
B) Divergent
C) Convergent-divergent
27. Number of bearings depends on
A) Length of engine rotor
B) Weight of engine rotor
C) Both A and B
28. What type of load do ball bearings carry.
A) Axial load
B) Radial load
C) Radial and thrust loads
29. Surface of material in bearing housing.
A) Land
B) Groove
C) Land – Groove
30. Ring seal is a.
A) Metal ring
B) Metal ring with groove
C) Fine wire brush bristles
31. Engine oil in GTE
A) Synthetic oil
B) Vegetable oil
C) Mineral oil
32. Which synthetic oil is better than mineral oil.
A) Less deposits, coke and lacquer
B) Good load carrying capacity
C) Good flowability and does not evaporate at high temperature
D) All of the above
33. Volatility of fuel means.
A) Conversion of liquid to vapour
B) Conversion of liquid to gas
C) Both A and B
34. The impurity of fuel which is very unique.
A) Water and fuel combining microorganisms.
B) Solid particles
35. The primary difference between pressure relief, full flow and total loss systems is.
A) Control of oil flow to bearings
B) Pressure differential
C) Temperature differential
36. The filter used in the last part of oil lubrication system (nozzle) is.
A) Fine mesh screen
B) Finger screen
C) Metal wire
37. Based on fuel control.
A) Inlet position (EASA 11.2)
B) Pump outlet
C) Gap between pump inlet and outlet
38. Which parameter does EEC serve during fuel metering.
A) Engine oil pressure (Cross and Wild 337)
B) Inlet temperature
C) Combustion chamber temperature
D) All of the above
39. Where is the turbine section located.
A) Upstream of the combustion chamber
B) Downstream of the combustion chamber
C) Upstream of the diffuser
40. Positive displacement means.
A) Constant supply for every revolution
B) Variable supply for every revolution
C) Fixed volume of fluid displaced per revolution
41. The pressure created by the most positive pressure pump is?
A) 100 to 200 PSI
B) 40 to 100 PSI (Cross and Wild 344)
C) 200 to 300 PSI
42. MTCS.
A) Air flow up to 1/5th of total engine core mass can be used for various functions
B) Air is used for engine bearing sealing atmosphere
C) Air is used to control turbine blade tip position
D) Inlet anti-icing by 28V DC supply
43. MTCS.
A) Catridge type starter used for commercial purpose
B) Catridge type starter used for slow starting
C) Air turbine starter using bleed air from ground equipment
D) All of the above
44. Air turbine starter bleed supply is by.
A) Ground supply
B) APU
C) Other engines
D) All of the above
45. EPR.
A) Compressor inlet to HP turbine outlet
B) Compressor inlet to compressor discharge outlet
C) Compressor inlet to jet pipe outlet
46. IEPR.
A) Integrated average of fan and gas generator exhaust pressure divided by inlet total pressure
B) Integrated of inlet pressure by exhaust pressure
C) Integrated exhaust pressure ratio
47. Oil temperature measured at.
A) Discharge of pump
B) Inlet of oil cooler
C) Inlet of pump
48. In the phonic wheel, an electric current can be used to induce which is amplified and then transmitted to an indicator. This method can be used to provide an indication of RPM without the need for.
A) Variable reluctance speed probe
B) Separately driven generator
49. In water injection, the water/methanol mixture.
A) It is also an additional source of fuel
B) Water gives anti-freezing properties
C) It is used for boosted power during takeoff
D) All of the above
50. In water injection.
A) 1/3rd inlet at low pressure and 2/3rd at compressor outlet at high pressure
B) 1/3rd high pressure at inlet and 2/3rd at low pressure outlet Compression
C) Water is injected in varying amounts at different stages of the compressor, depending on the system design.
51. In afterburner, thrust is obtained due to.
A) Increase in exhaust velocity
B) Decrease in exhaust velocity
C) Increase in flame spread
52. Ignition system in GTE.
A) Continuous
B) Short time till completion of starting cycle
C) Short duration till takeoff
53. Starter motor automatically stops when the starter drive speed exceeds the output shaft speed.
A) Output shaft
B) Splined output shaft
C) Internal governor speed
D) All of the above
54. MTCS.
A) Two types of turboprop turbines – fixed and free
B) Free turbine is connected to the fixed turbine by air
C) Fixed turbine is directly connected to the RGB and propeller
D) All of the above
55. Overspeed protection for turboprop.
A) Hydromechanical unit that increases blade angle with speed increase more than 100%
B) An electronic unit as backup to the propeller governor
C) As in (B) + there is a knob in the cockpit for adjustment
56. What does the gas generator section of a turboshaft include.
A) Compressor, combustion chamber
B) Compressor, combustion chamber with igniter and fuel nozzle
C) Compressor, combustion chamber with igniter and fuel nozzle and one or more stages of turbine
57. What does the power section of a turboshaft include.
A) Compressor, combustion chamber, and turbine
B) Additional stages of turbine, a gear reduction system and shaft output
58. MTCS for turboprop.
A) In a fixed turbine engine, all turbine stages are connected to a single shaft
B) In a free turbine, the turbine stages are connected to two completely independent shafts
C) One shaft rotates the engine compressor. The other shaft rotates the propeller via a reduction gearbox
D) All of the above
59. MTCS for turboshaft.
A) About 2/3 of the energy produced by the helicopter turboshaft engine is used to operate a gas generator
B) About 1/3 of the energy produced by the helicopter turboshaft engine is used to operate a gas generator
C) About 3/4 of the energy produced by the helicopter turboshaft engine is used to operate a gas generator
60. What is an APU used for.
A) Main engine starting
B) In-flight emergency
C) Ground power support not available
D) All of the above
61. APU supplies electrical power from.
A) 115V, single phase, 50HZ
B) 115V, single phase, 400HZ
C) 115V, 3-phase, 400HZ
62. Cooling period for APU.
A) From after shutdown till next start attempt
B) Running APU without load before shutdown
C) Both
63. Teacher’s objective.
A) Cooling for APU
B) Exhaust for APU
C) Pneumatic supply
64. Starter motor is directly coupled to.
A) Load compressor
B) RGB
C) Gas generator*
65. MTCS.
A) Fuel line clamps should not be attached to the aircraft structure
B) If physical separation is not possible the fuel line should be placed above the electrical wiring loop
C) Electrical wire line loops are always placed above the fuel line in the aircraft structure
66. Engine power lever control cables and pushpull rods… rigging required.
A) From pylon to engine
B) From airframe to pylon
67. The three most common fire detection systems used in aircraft engines are.
A) Rate-of-rise, radiation sensing and overheat detectors
B) Rate-of-rise, smoke detectors and overheat detectors
C) Rate-of-rise, smoke detectors and flame detectors
68. MTCS for discharge indicator.
A) Red disc for thermal discharge
B) Yellow disc for crew discharge
C) As per (A) and (B) + red is for normal discharge
D) As per (A) and (B) + yellow is for normal discharge
69. If fire breaks out in RH engine.
A) Both engine fire warning lights come on
B) Only one light will come on
C) As in (B) + Switch in cockpit to extinguish discharge
D) All of the above
70. Marking material for combustion section parts – used in engine gas path.
A) Layout dye or chalk
B) Metal pencil
C) Wax pencil
71. During compressor washing, cleaning is done with water or a mixture of water and cleaning solution.
A) Only the compressor is cleaned
B) The entire gas path is cleaned
C) The turbine is cleaned
72. Substances that absorb moisture from the atmosphere (desiccants) – where are they kept.
A) Around
B) In
C) In and around
73. Power increase depends on.
A) Type of coolant
B) Propulsion of the component
C) Amount of coolant
D) All of the above
74. Anti-ice system properties.
A) Reliable
B) Weight penalty should not be imposed
C) Minimum maintenance requirement
D) All of the above
75. Correct angle of air flow is controlled by.
A) VIGV and VSV
B) VIGV and fixed stator vane
C) Fixed IGV and VSV
D) Fixed IGV and fixed stator vane
76. Fire detection system false alert.
A) Detector too close to hot material
B) Loose electrical connection
C) Dirt and dust accumulated on detector
D) All of the above
77. The number of turbines on an engine depends on.
A) Combustion chamber
B) Compressor driving
C) Load driving the turbine
78. Nose cowling.
A) Upper and lower panel, hinged cowling and fixed
B) Side and bottom
C) Right and left of engine
79. The procedure for preserving and protecting gas turbine engines differs depending on.
A) Period of inactivity
B) Type of preservative used
C) and whether the engine can be rotated during the inactive period
D) All of the above
80. The engine should be preserved till 7th day for?
A) Engine should be rotated weekly
B) Blank off only after every operation
C) Engine should not be preserved at all after operations.
81. MTCS for combustion chamber.
A) Primary air is introduced inside the liner at the front end
B) Secondary air passes through the outer casing and liner
C) Primary air passes through the outer casing and liner
D) Both (A) and (B)
82. Low fuel volatiles are required for.
A) To prevent vapour lock
B) To prevent ice formation
C) Both (A) and (B)
83. Torquemeter indication transmits power from.
A) From engine to accessory drive section
B) From RGB to propeller
C) From Engine to RGB
84. What is a discharge resistor used for.
A) To increase the duration of ignition
B) To protect the unit from excessive voltage
C) To discharge residual stored energy (voltage) after the engine is shut down
85. What type of ignition system is used by high energy ignition units.
A) Tank unit
B) Storage capacitor
C) Storage reactor
D) None
86. By which method is high energy ignition accomplished.
A) Capacitor discharge
B) Transistor
C) Resistor
87. What is used to dissipate energy after shutdown.
A) Resistor
B) Bleeder resistor
C) Choke
88. Can-annular combustion chambers also have the required fuel drain valve located in.
A) two or more lower chambers
B) ensuring proper drainage and elimination of residual fuel burning at the next start
C) Both (a) and (b) are correct
89. Fuel manifolds are drained by an individual unit known as a drip or dump valve. This type of valve may be operated by.
A) pressure differential, or it may be solenoid operated
B) The fuel is kept closed by pressure during engine operation
C) Both (a) and (b) are correct
90. Short duct high bypass engine.
A) Core air and fan air are two streams which are drawn separately through two coaxial nozzles
B) Core air and fan air have a common (integrated) nozzle which starts mixing the gases before they exit the nacelle
C) Both (a) and (b) are correct
91. What is the primary function of a thrust Reverse.
A) To provide reverse thrust for deceleration
B) To increase engine efficiency
C) To reduce engine noise
D) To maintain aircraft speed during descent
92. What does a constant speed drive (CSD) in a turboprop engine control.
A) The speed of the alternator
B) The turbine rotation speed
C) The power output from the engine
D) The pitch of the propeller blades
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