Powerplant - Turbine Engines

The turbine section of a jet engine

A increases air velocity to generate thrust forces.

B utilizes heat energy to expand and accelerate the incoming gas flow.

C drives the compressor section.

C drives the compressor section.

Explanation

One of the major functions of the turbine section in a turbojet or turbofan engine is to drive the compressor.

The highest heat-to-metal contact in a jet engine is the

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burner cans.

turbine inlet guide vanes.

turbine blades.

turbine inlet guide vanes.

Stator blades in the compressor section of an axial-flow turbine engine

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increase the air velocity and prevent swirling.

straighten the airflow and accelerate it.

decrease the air velocity and prevent swirling.

decrease the air velocity and prevent swirling.

Generally, when starting a turbine engine, the starter should be disengaged

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after the engine has reached self-accelerating speed.

only after the engine has reached full idle RPM.

when the ignition and fuel system are activated.

after the engine has reached self-accelerating speed.

When starting a turbine engine,

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a hot start is indicated if the exhaust gas temperature exceeds specified limits.

an excessively lean mixture is likely to cause a hot start.

release the starter switch as soon as indication of light-ott occurs.

a hot start is indicated if the exhaust gas temperature exceeds specified limits.

What is the profile of a turbine engine compressor blade?

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The leading edge of the blade.

A reduced blade tip thickness.

The curvature of the blade root.

A reduced blade tip thickness.

The blending of blades and vanes in a turbine engine

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is usually accomplished only at engine overhaul.

should be performed parallel to the length of the blade using smooth contours to minimize stress points.

may sometimes be accomplished with the engine installed, ordinarily using power tools.

should be performed parallel to the length of the blade using smooth contours to minimize stress points.

Usually, most of the load placed on an APU occurs when

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an electrical load is placed on the generator (s).

the bleed air valve is opened.

the bleed air valve is closed.

the bleed air valve is opened.

What is used in turbine engines to aid in stabilization of compressor airflow during low thrust engine operation?

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Stator vanes and rotor vanes.

Variable guide vanes and/or compressor bleed valves.

Pressurization and dump valves.

Variable guide vanes and/or compressor bleed valves.

The stators in the turbine section of a gas turbine engine

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increase the velocity of the gas flow.

decrease the velocity of the gas flow.

increase the pressure of the gas flow.

increase the velocity of the gas flow.

Anti-icing of jet engine air inlets is commonly accomplished by

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electrical heating elements inside the inlet guide vanes.

engine bleed air ducted through the critical areas.

electrical heating elements located within the engine air inlet cowling.

engine bleed air ducted through the critical areas.

Anti-icing of jet engine air inlets is commonly accomplished by

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electrical heating elements inside the inlet guide vanes.

engine bleed air ducted through the critical areas.

electrical heating elements located within the engine air inlet cowling.

engine bleed air ducted through the critical areas.

If the RPM of an axial-flow compressor remains constant, the angle of attack of the rotor blades can be changed by

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changing the velocity of the airflow.

changing the compressor diameter.

increasing the pressure ratio.

changing the velocity of the airflow.

Hot section inspections for many modern turbine engines are required

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only at engine overhaul.

only when an overtemperature or overspeed has occurred.

on a time or cycle basis.

on a time or cycle basis.

An exhaust cone placed aft of the turbine in a jet engine will cause the pressure in the first part of the exhaust duct to

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increase and the velocity to decrease.

increase and the velocity to increase.

decrease and the velocity to increase.

increase and the velocity to decrease.

What is the primary factor which controls the pressure ratio of an axial-flow compressor?

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Number of stages in compressor.

Compressor inlet pressure.

Compressor inlet temperature.

Number of stages in compressor.

Who establishes the recommended operating time between overhauls (TBO) of a turbine engine used in general aviation?

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The engine manufacturer.

TBO does not apply to turbine engines.

The aircraft manufacturer.

The engine manufacturer.

Which of the following statements is true regarding the basic gas turbine engine?

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The engine is divided into three sections: cold, neutral, and hot sections.

The cold section includes the engine inlet, diffuser, and compressor sections.

The hot section includes the combustor, diffuser, and exhaust sections.

The cold section includes the engine inlet, diffuser, and compressor sections.

The diffuser section of a jet engine is located between

the burner section and the turbine section.

station 7 and station 8.

the compressor section and the burner section.

the compressor section and the burner section.

If a turbine engine is unable to reach takeoff EPR before its EGT limit is reached, this is an indication that the

fuel control must be replaced.

EGT controller is out of adjustment.

compressor may be contaminated or damaged.

compressor may be contaminated or damaged.

When aircraft turbine blades are subjected to excessive heat stress, what type of failures would the aviation mechanic expect?

Bending and torsion.

Torsion and tension.

Stress rupture.

Stress rupture.

The stators in the turbine section of a gas turbine engine

increase the velocity of the gas flow.

decrease the velocity of the gas flow.

increase the pressure of the gas flow.

increase the velocity of the gas flow.

A turbine engine compressor which contains vanes

on both sides

of the impeller is

double entry centrifugal compressor.

double entry axial-flow compressor.

single entry axial-flow compressor.

double entry centrifugal compressor.

The compressor stators in a gas turbine engine act as diffusers to

decrease the velocity of the gas flow.

increase the velocity of the gas flow.

increase the velocity and decrease the pressure of the gas.

decrease the velocity of the gas flow.

During a maintenance run, a turbine engine produces lower-than-expected thrust and higher-than-normal EGT at the specified RPM. Which condition is the most likely cause?

Faulty fuel flow transmitter.

Low oil pressure.

Fuel control unit out of adjustment.

Explanation:

If the fuel control is improperly adjusted, the engine may not produce the required EGT or EPR at a specified RPM. A high EGT with reduced performance during a run-up can indicate

Fuel control unit out of adjustment.

Explanation:

If the fuel control is improperly adjusted, the engine may not produce the required EGT or EPR at a specified RPM. A high EGT with reduced performance during a run-up can indicate

A weak fuel to air mixture along with normal airflow through a turbine engine may result

a rich flameout.

a lean die-out.

high EGT.

a lean die-out.

When starting a turbine engine, a hung start is indicated if the engine

A exhaust gas temperature exceeds specified limits.

B fails to reach idle RPM.

C N(1) is normal, but N(2) is low.

fails to reach idle RPM.

Which of the following statements is true regarding a turbine engine axial-flow compressor?

Each parallel pair of rotor blades and stator vanes constitutes a pressure stage.

The number of rows of stages is determined by the amount of air and total pressure rise required.

Each consecutive pair of rotor blades and stator vanes constitutes a pressure stage.

Each consecutive pair of rotor blades and stator vanes constitutes a pressure stage.

Turbine engine components exposed to high temperatures generally may not be marked with

layout dye, commercial felt tip marker, or chalk.

wax, grease pencil, or a graphite lead pencil.

commercial felt tip marker or grease pencil.

wax, grease pencil, or a graphite lead pencil.

What is the first engine instrument indication of a successful start of a turbine engine?

A rise in engine RPM.

A rise in oil temperature.

A rise in the exhaust gas temperature.

A rise in the exhaust gas temperature.

Main bearing oil seals used with turbine engines are usually what type(s)?

Labyrinth and/or carbon rubbing.

Teflon and synthetic rubber.

Labyrinth and/or silicone rubber.

Labyrinth and/or carbon rubbing.

Which of the following is a good indication of a malfunctioning fuel nozzle when inspecting the exhaust section of an aircraft turbine engine?

Buckling of the combustion liner.

Hotspots on the tail cone.

Carbon build up in the exhaust.

Hotspots on the tail cone.

What is meant by a shrouded turbine?

The turbine blades are shaped so that their ends form a band or shroud.

The turbine wheel is enclosed by a protective shroud to contain the blades in case of failure.

The turbine wheel has a shroud or duct which provides cooling air to the turbine blades.

The turbine blades are shaped so that their ends form a band or shroud.

Which turbine engine compressor offers the greatest advantages for both starting flexibility and improved high-altitude performance?

Dual-stage, centrifugal-flow.

Split-spool, axial-flow.

Single-spool, axial-flow.

Split-spool, axial-flow.

In a gas turbine engine, combustion occurs at a constant

volume.

pressure.

density.

pressure

What is the primary factor which controls the pressure ratio of an axial-flow compressor?

Number of stages in compressor.

Compressor inlet pressure.

Compressor inlet temperature.

Number of stages in compressor.

Where do stress rupture cracks usually appear on turbine blades?

Across the blade root, parallel to the fir tree.

Along the leading edge, parallel to the edge.

Across the leading or trailing edge at a right angle to the edge length.

Across the leading or trailing edge at a right angle to the edge length.

Which of the following engine variables is the most critical during turbine engine operation?

Compressor inlet air temperature.

Compressor RPM.

Turbine-inlet temperature.

Turbine-inlet temperature.

The two types of centrifugal compressor impellers are

single entry and double entry.

rotor and stator.

impeller and diffuser.

single entry and double entry.

An advantage of the axial-flow compressor is its

low starting power requirements.

low weight.

high peak efficiency.

high peak efficiency.

What is the function of the inlet guide vane assembly on an axial-flow compressor?

Directs the air into the first stage rotor blades at the proper angle.

Converts velocity energy into pressure energy.

Converts pressure energy into velocity energy.

Directs the air into the first stage rotor blades at the proper angle.

In which type of turbine engine combustion chamber is the case and liner removed and installed as one unit during routine maintenance?

Can.

Can-annular.

Annular.

Can

Which of the following types of combustion sections are used in aircraft turbine engines?

Annular, variable, and cascade vane.

Can, multiple-can, and variable.

Multiple-can, annular, and can-annular.

Multiple-can, annular, and can-annular.

What type of turbine blade is most commonly used in aircraft jet engines?

Reaction.

Impulse.

Impulse-reaction.

Impulse-reaction.

What is the primary advantage of an axial-flow compressor over a centrifugal compressor?

High frontal area.

Less expensive.

Greater pressure ratio.

Greater pressure ratio.

The compressor stators in a gas turbine engine act as diffusers to

decrease the velocity of the gas flow.

increase the velocity of the gas flow.

increase the velocity and decrease the pressure of the gas.

decrease the velocity of the gas flow.

Three types of turbine blades are

impulse, converging, and impulse-converging.

impulse, reaction, and impulse-reaction.

impulse, diverging, and impulse-diverging.

impulse, reaction, and impulse-reaction

Which of the following acts as a diffuser in a turbine engine and converts velocity to pressure?

Impeller.

Manifold.

Stators.

Stators

The stator vanes in an axial-flow compressor

convert velocity energy into pressure energy.

convert pressure energy into velocity energy.

direct air into the first stage rotor vanes at the proper angle.

convert velocity energy into pressure energy.

Fuel is normally supplied to an APU from the

APU independent fuel tank.

airplane's header fuel tank.

airplane's main fuel tank.

airplane's main fuel tank.

What must be done after the fuel control unit has been replaced on an aircraft gas turbine engine?

Perform a full power engine run to check fuel flow.

Recalibrate the fuel nozzles.

Retrim the engine.

Retrim the engine.

The Brayton cycle is known as the constant

pressure cycle.

temperature cycle.

mass cycle.

pressure cycle.

In a turbine engine with a dual-spool compressor, the low speed compressor

always turns at the same speed as the high speed compressor.

is connected directly to the high speed compressor.

seeks its own best operating speed.

seeks its own best operating speed.

What is the major function of the turbine assembly in a turbojet engine?

Directs the gases in the proper direction to the tailpipe.

Supplies the power to turn the compressor.

Increases the temperature of the exhaust gases.

Supplies the power to turn the compressor.

In the dual axial-flow or twin spool compressor system, the first stage turbine drives the

N(1) and N(2) compressors.

N(2) compressor.

N(1) compressor

N(2) compressor.

Hot spots in the combustion section of a turbojet engine are possible indicators of

faulty igniter plugs.

dirty compressor blades.

malfunctioning fuel nozzles.

malfunctioning fuel nozzles.

A gas turbine engine comprises which three main sections?

Compressor, diffuser, and stator.

Turbine, combustion, and stator.

Turbine, compressor, and combustion.

Turbine, compressor, and combustion.

Where is the highest gas pressure in a turbojet engine?

At the outlet of the tailpipe section.

At the entrance of the turbine section.

In the entrance of the burner section.

In the entrance of the burner section.