Questions and Answers - Turbine Engine (Part 2) | Aircraft Systems

Questions and Answers - Turbine Engine (Part 2)

Multiple Choices Questions

61. Hot section inspections for many modern turbine engines are required
a. only at engine overhaul.
b. only when an overtemperature or overspeed has occurred.
c. on a time or cycle basis.

62. A purpose of the shrouds on the turbine blades of an axial-flow engine is to
a. reduce vibration.
b. increase tip speed.
c. reduce air entrance.

63. In a dual axial-flow compressor, the first stage turbine drives
a. N2 compressor.
b. N1 compressor.
c. low pressure compressor.

64. What should be done initially if a turbine engine catches fire when starting?
a. Turn off the fuel and continue engine rotation with the starter.
b. Continue engine start rotation and discharge a fire extinguisher into the intake.
c. Continue starting attempt in order to blow out the fire.

65. What is the proper starting sequence for a turbojet engine?
a. Ignition, starter, fuel.
b. Starter, ignition, fuel.
c. Starter, fuel, ignition.


66. A weak fuel to air mixture along with normal aifflow through a turbine engine may result in
a. a rich flameout.
b. a lean die-out.
c. high EGT.

67. What is used in turbine engines to aid in stabilization of compressor airflow during low thrust engine operation?
a. Stator vanes and rotor vanes.
b. Variable guide vanes and/or compressor bleed valves.
c. Pressurization and dump valves.

68. In a turbine engine with a dual-spool compressor, the low speed compressor
a. always turns at the same speed as the high speed compressor.
b. is connected directly to the high speed compressor.
c. seeks its own best operating speed.

69. What is the function of the inlet guide vane assembly on an axial-flow compressor?
a. Directs the air into the first stage rotor blades at the proper angle.
b. Converts velocity energy into pressure energy.
c. Converts pressure energy into velocity energy.

70. Hot spots on the tail cone of a turbine engine are possible indicators of a malfunctioning fuel nozzle or
a. a faulty combustion chamber.
b. a faulty igniter plug.
c. an improperly positioned tail cone.

71. The stator vanes in an axial-flow compressor
a. convert velocity energy into pressure energy.
b. convert pressure energy into velocity energy.
c. direct air into the first stage rotor vanes at the proper angle.

72. The velocity of subsonic air as it flows through a convergent nozzle
a. increases.
b. decreases.
c. remains constant.

73. The velocity of supersonic air as it flows through a divergent nozzle
a. increases.
b. decreases.
c. is inversely proportional to the temperature.

74. The pressure of subsonic air as it flows through a convergent nozzle
a. increases.
b. decreases.
c. remains constant.

75. The pressure of supersonic air as it flows through a divergent nozzle
a. increases.
b. decreases.
c. is inversely proportional to the temperature.

76. Anti-icing of jet engine air inlets i s commonly accomplished by
a. electrical heating elements inside the inlet guide vanes.
b. engine bleed air ducted through the critical areas.
c. electrical heating elements located within the engine air inlet cowling.

77. Generally, when starting a turbine engine, the starter should be disengaged
a. after the engine has reached self-accelerating speed.
b. only after the engine has reached full idle RPM.
c. when the ignition and fuel system are activated.

78. What is the primary advantage of an axial-flow compressor over a centrifugal compressor?
a. High frontal area.
b. Less expensive.
c. Greater pressure ratio.

79. The purpose of a bleed valve, located in the beginning stages of the compressor, in an aircraft gas turbine engine is to
a. vent some of the air overboard to prevent a compressor stall.
b. control excessively high RPM to prevent a compressor stall.
c. vent high ram air pressure overboard to prevent a compressor stall.

80. What is meant by a double entry centrifugal compressor?
a. A compressor that has two intakes.
b. A two-stage compressor independently connected to the main shaft.
c. A compressor with vanes on both sides of the impeller.


81. What is the major function of the turbine assembly in a turbojet engine?
a. Directs the gases in the proper direction to the tailpipe.
b. Supplies the power to turn the compressor.
c. Increases the temperature of the exhaust gases.

82. Stator blades in the compressor section of an axialflow turbine engine
a. increase the air velocity and prevent swirling.
b. straighten the airflow and accelerate it.
c. decrease the air velocity and prevent swirling.

83. A gas turbine engine comprises which three main sections?
a. Compressor, diffuser, and stator.
b. Turbine, combustion, and stator.
c. Turbine, compressor, and combustion.

84. What type of turbine blade is most commonly used in aircraft jet engines?
a. Reaction.
b. Impulse.
c. Impulse-reaction.

85. What is the primary factor which controls the pressure ratio of an axial-flow compressor?
a. Number of stages in compressor.
b. Compressor inlet pressure.
c. Compressor inlet temperature.

86. The non-rotating axial-flow compressor airfoils in an aircraft gas turbine engine are called
a. pressurization vanes.
b. stator vanes.
c. bleed vanes.

87.
(1) In a turbine engine axial-flow compressor, each consecutive pair of rotor and stator blades constitutes a pressure stage.
(2) In a turbine engine axial-flow compressor, the number of rows of stages is determined by the amount of air and total pressure rise required.

Regarding the above statements,
a. only No. 1 is true.
b. only No.2 is true.
c. both No.1 and No.2 are true.

88. The air passing through the combustion chamber of a turbine engine is
a. used to support combustion and to cool the engine.
b. entirely combined with fuel and burned.
c. speeded up and heated by the action of the turbines.

89. The stators in the turbine section of a gas turbine engine
a. increase the velocity of the gas flow.
b. decrease the velocity of the gas flow.
c. increase the pressure of the gas flow.

90. The compressor stators in a gas turbine engine act as diffusers to
a. decrease the velocity of the gas flow.
b. increase the velocity of the gas flow.
c. increase the velocity and decrease the pressure of the gas.

91. The procedure for removing the accumulation of dirt deposits on compressor blades is called
a. the soak method.
b. field cleaning.
c. the purging process.

92. Which of the following may be used to accomplish internal inspection of an assembled turbine engine?
1. Infrared photography.
2. Ultrasound.
3. A borescope.
4. Fluorescent penetrant and ultraviolet light.

a. 1, 2, 3.
b. 1, 3.
c. 3.

93. What is the possible cause when a turbine engine indicates no change in power setting parameters, but oil temperature is high?
a. High scavenge pump oil flow.
b. Engine main bearing distress.
c. Turbine damage and/or loss of turbine efficiency.

94. Newton's First Law of Motion, generally termed the Law of Inertia, states:
a. To every action there is an equal and opposite reaction.
b. Force is proportional to the product of mass and acceleration.
c. Every body persists in its state of rest, or of motion in a straight line, unless acted upon by some outside force.

95. A turbine engine hot section is particularly susceptible to which kind of damage?
a. Scoring.
b. Cracking.
c. Galling.


96. Dirt particles in the air being introduced into the compressor of a turbine engine will form a coating on all but which of the following?
a. Turbine blades.
b. Casings.
c. Inlet guide vanes.

97. Severe rubbing of turbine engine compressor blades will usually cause
a. bowing.
b. cracking.
c. galling.

98. Which of the following influences the operation of an automatic fuel control unit on a turbojet engine?
a. Burner pressure.
b. Mixture control position.
c. Exhaust gas temperature.

99. If a turbine engine is unable to reach takeoff EPR before its EGT limit is reached, this is an indication that the
a. fuel control must be replaced.
b. EGT controller is out of adjustment.
c. compressor may be contaminated or damaged.

100. The Brayton cycle is known as the constant
a. pressure cycle.
b. temperature cycle.
c. mass cycle.

101. Continued and/or excessive heat and centrifugal force on turbine engine rotor blades is likely to cause
a. profile.
b.- creep.
c.- galling.

102. If the RPM of an axial-flow compressor remains constant, the angle of attack of the rotor blades can be changed by
a. changing the velocity of the airflow.
b. changing the compressor diameter.
c. increasing the pressure ratio.

103. The compression ratio of an axial-flow compressor is a function of the
a. number of compressor stages.
b. rotor diameter.
c. air inlet velocity.

104. Which of the following variables affect the inlet air density of a turbine engine?
1. Speed of the aircraft.
2. Compression ratio.
3. Turbine inlet temperature.
4. Altitude of the aircraft.
5. Ambient temperature.
6. Turbine and compressor efficiency.

a. 1, 3, 6.
b. 1, 4, 5.
c. 4, 5, 6.

105. Which of the following factors affect the thermal efficiency of a turbine engine?
1. Turbine inlet temperature.
2. Compression ratio.
3. Ambient temperature.
4. Speed of the aircraft.
5. Turbine and compressor efficiency.
6. Altitude of the aircraft.

A - 3, 4, 6.
B - l, 2, 5.
C- l, 2, 6.

106. Why do some turbine engines have more than one turbine wheel attached to a single shaft?
a. To facilitate balancing of the turbine assembly.
b. To help stabilize the pressure between the compressor and the turbine.
c. To extract more power from the exhaust gases than a single wheel can absorb.

107. The exhaust section of a turbine engine is designed to
a. impart a high exit velocity to the exhaust gases.
b. increase temperature, therefore increasing velocity.
c. decrease temperature, therefore decreasing pressure.

108. Which of the following types of combustion sections are used in aircraft turbine engines?
a. Annular, variable, and cascade vane.
b. Can, multiple-can, and variable.
c. Multiple-can, annular, and can-annular.

109. A cool-off period prior to shutdown of a turbine engine is accomplished in order to
a. allow the turbine wheel to cool before the case contracts around it.
b. prevent vapor lock in the fuel control and/or fuel lines.
c. prevent seizure of the engine bearings.

110. What type of igniter plug is used in the low tension ignition system of an aircraft turbofan engine?
a. Low voltage, high amperage glow plug.
b. Self-ionizing or shunted-gap type plug.
c. Recessed surface gap plug.

111. What is meant by a shrouded turbine?
a. The turbine blades are shaped so that their ends form a band or shroud.
b. The turbine wheel is enclosed by a protective shroud to contain the blades in case of failure.
c. The turbine wheel has a shroud or duct which provides cooling air to the turbine blades.

112. What term is used to describe a permanent and cumulative deformation of the turbine blades of a turbojet engine?
a. Stretch.
b. Distortion.
c. Creep.

113. What is the purpose of the dump valve used on aircraft gas turbine engines?
a. The fuel is quickly cut off to the nozzles and the manifolds are drained preventing fuel boiling as a result of residual engine heat.
b. The valve controls compressor stalls by dumping compressor bleed air from the compressor discharge port under certain conditions.
c. Maintains minimum fuel pressure to the engine fuel control unit inlet and dumps excessive fuel back to the inlet of the engine driven fuel pump.

114. At what stage in a turbine engine are gas pressures the greatest?
a. Compressor inlet.
b. Turbine outlet.
c. Compressor outlet.

115. In what section of a turbojet engine is the jet nozzle located?
a. Combustion.
b. Turbine.
c. Exhaust.

116.
(I) Accumulation of contaminates in the compressor of a turbojet engine reduces aerodynamic efficiency of the blades.
(2) Two common methods for removing dirt deposits from turbojet engine compressor blades are a fluid wash and an abrasive grit blast.

Regarding the above statements,
a. only No. 1 is true.
b. only No. 2 is true.
c. both No. 1 and No. 2 are true.

117. Hot spots in the combustion section of a turbojet engine are possible indicators of
a. faulty igniter plugs.
b. dirty compressor blades.
c.- malfunctioning fuel nozzles.

118. Which of the following can cause fan blade shingling in a turbofan engine?
1. Engine overspeed.
2. Engine overtemperature.
3. Large, rapid throttle movements.
4. FOD.

a. 1, 2.
b. 1, 2, 3, 4.
c. 1, 4.

119. Compressor stall is caused by
a. a low angle of attack airflow through the first stages of compression.
b. a high angle of attack airflow through the first stages of compression.
c. rapid engine deceleration.

120. A condition known as "hot streaking" in turbine engines is caused by
a. a partially clogged fuel nozzle.
b. a misaligned combustion liner.
c. excessive fuel flow.



SUPPORTING LESSONS