Flight Operations 1

Question 1

One of the main advantages of the axial flow compressor type of gas turbine engine as compared to the centrifuge type is:

A) Comparatively small frontal area of the compressor.
B) Lower weight.
C) Increased efficiency over a wider RPM range.
D) Ease of manufacture.

Answer 1

A) Comparatively small frontal area of the compressor.

Question 2

That section of a turbine engine which extracts energy from the expanding high velocity combustion gases to drive the compressor section(s) and fan (or propeller) is the:

A) Diffuser section.
B) Turbine section.
C) Booster fan section.
D) Accessory drive section.

Answer 2

B) Turbine section.

Question 3

That component of a gas turbine engine which is located at the outlet side of a centrifugal compressor and whose function is to convert high velocity airflow into high pressure airflow for delivery to the combustion section is known as the:

A) Booster fan section.
B) Convergent delivery duct.
C) Planetary drive section.
D) Diffuser section.

Answer 3

D) Diffuser section.

Question 4

The majority of the energy produced in the burner section of a turbojet engine is used for:

A) Engine thrust.
B) Hot bleed air.
C) Running the engine compressor.
D) Engine noise.

Answer 4

C) Running the engine compressor.

Question 5

In a turbofan engine, why is bypassed air more efficient at creating engine thrust?

A) Cooler bypassed air is more dense than hot exhaust air, therefore containing more energy.
B) The burned fuel mixed with the core air does not produce usable thrust.
C) It is not more efficient, the benefit to bypassed air is a reduction in noise.
D) Since bypassed air is not used to rotate the compressor section of the engine it can produce more forward thrust.

Answer 5

A) Cooler bypassed air is more dense than hot exhaust air, therefore containing more energy.

Question 6

Engine N1 and N2 gauges are an indication of what?

A) The rotation rate of the compressor and turbine sections respectively, expressed as a percentage.
B) Alternative ways of displaying EPR on digital EFIS displays.
C) Percentage of thrust the engine is producing (N1) as compared to what it should be producing (N2).
D) The rotation rate of the low and high pressure compressors respectively, expressed as a percentage.

Answer 6

D) The rotation rate of the low and high pressure compressors respectively, expressed as a percentage.

Question 7

When starting a gas turbine engine the two primary gauges to observe are:

A) The low pressure compressor and the exhaust gas temperature.
B) The propeller RPM and the exhaust gas temperature.
C) The high pressure compressor and internal turbine temperature.
D) The compressor turbine and the free turbine.

Answer 7

C) The high pressure compressor and internal turbine temperature.

Question 8

The relationship between the mass flow of cold air through the fan to the mass flow of the hot air through the turbine is known as the:

A) Recovery ratio.
B) Bypass ratio.
C) Power extraction ratio.
D) Engine pressure ratio,

Answer 8

B) Bypass ratio.

Question 9

What provides the rotational energy for an axial flow compressor in a turbojet engine?

A) The low pressure compressor obtains energy from the high pressure compressor which has a higher rotational rate.
B) Electrical energy produced from a generator attached to a constant speed drive.
C) The engine turbine using bleed air transferred through high stage bleed ducts.
D) The engine turbine using energy from hot exhaust gases exiting the engines burner section.

Answer 9

D) The engine turbine using energy from hot exhaust gases exiting the engines burner section.

Question 10

What occurs in the burner section of a gas turbine?

A) Fuel is mixed with compressed air then ignited to create the energy needed to run the engine.
B) The fuel/air mixture which enters the burner is ignited to create the energy needed to run the engine.
C) Excess fuel not used to produce thrust is collected here and ignited in order to run the engines compressor.
D) Fuel is mixed with air and ignited before moving through the engine compressor and turbine.

Answer 10

A) Fuel is mixed with compressed air then ignited to create the energy needed to run the engine.

Question 11

EPR (Engine Pressure Ratio) is correctly defined as:

A) The ratio of turbine discharge total pressure to the total pressure at the compressor inlet.
B) The ratio of engine compressor discharge pressure to the engine inlet total pressure.
C) The ratio of turbine inlet pressure to turbine discharge pressure.
D) The ratio of fan section airflow to basic engine airflow.

Answer 11

A) The ratio of turbine discharge total pressure to the total pressure at the compressor inlet.

Question 12

Compressor stall is caused by:

A) The fuel control unit scheduling an inadequate fuel flow to the primary fuel nozzles.
B) Below normal internal temperatures at the power turbine section.
C) Excessive angle of attack on the compressor blades.
D) Stator blade warping when the engine is operating at a high EPR setting.

Answer 12

C) Excessive angle of attack on the compressor blades.

Question 13

In identifying a compressor stall condition, which of the following would be the predominant symptoms?

1) Loud explosive bangs.
2) High oil temperature.
3) Lower EGT or ITT readings.
4) Lower torque or N1 readings.
5) Higher than normal fuel.
6) Higher compressor readings flow.
7) Higher EGT or ITT readings
8) Engine Surging

A) 1, 4, 7, 8.
B) 1, 3, 5, 8.
C) 3, 4, 6, 8.
D) 2, 4, 6, 7.

Answer 13

A) 1, 4, 7, 8.

Question 14

The purpose of a compressor bleed valve in a gas turbine engine is to:

A) Provide hot air for anti-ice purposes.
B) Maintain a constant pressure across compressor and turbine sections of the engine.
C) Regulate gas generator RPM during rapid acceleration of the engine.
D) Reduce the possibility of compressor stall.

Answer 14

D) Reduce the possibility of compressor stall.

Question 15

The stationary blade-type airfoil devices that are installed between each compressor stage in order to direct the airflow into succeeding stages at the optimum angle in an axial flow compressor are known as:

A) Cascade vanes.
B) Stators.
C) Impeller blades.
D) Diffuser vanes.

Answer 15

B) Stators.

Question 16

A “hung” or false start of a gas turbine engine is one in which:

A) The engine lights up, but the exhaust gas temperature exceeds the allowable limit for an engine start.
B) The engine lights up normally, but the RPM, rather than increasing to idling speed, remains at some lower speed.
C) Too high fuel flow was scheduled before the engine attained self-accelerating speed.
D) The engine shaft bows preventing rotation of the compressors.

Answer 16

B) The engine lights up normally, but the RPM, rather than increasing to idling speed, remains at some lower speed.

Question 17

Which of the following statements is true with reference to an engine hot start?

A) The engine lights up normally, but the RPM, rather than increasing to that of idle speed, remains at some lower value.
B) The engine lights up normally however the exhaust gas temperature readings are higher than a normal start.
C) During the start the internal turbine temperatures exceed the maximum allowable limit potentially causing damage to internal engine components.
D) During the start the exhaust gas temperature exceeds the maximum allowable limit potentially causing damage to the engine cowlings and tailpipe.

Answer 17

C) During the start the internal turbine temperatures exceed the maximum allowable limit potentially causing damage to internal engine components.

Question 18

When air is extracted from the compressor section for service functions such as air conditioning or anti-icing, then:

A) Thrust will decrease and turbine temperature will decrease.
B) Thrust will increase due to increased combustion chamber efficiency.
C) Thrust will decrease and turbine temperature will increase.
D) Thrust will increase and exhaust gas temperature will decrease.

Answer 18

C) Thrust will decrease and turbine temperature will increase.

Question 19

Which of the following is true with reference to thrust reversers on turbofan engines?

A) Clamshell type reversers are mounted around the engine exhaust duct and can only redirect the hot gases exiting from the hot section forward.
B) Target type reversers utilize target doors and turning vanes to redirect both hot and cold thrust forward.
C) On cascade type reversers, blocker doors seal off the fan exit as a sleeve moves to expose the cascade vanes.
D) Variable Fan Reversers adjust the pitch of the fan blades to redirect the fan air forward.

Answer 19

C) On cascade type reversers, blocker doors seal off the fan exit as a sleeve moves to expose the cascade vanes.

Question 20

On a low-bypass turbofan engine, how much of engine thrust is reversed when clamshell type engine reversers are deployed on landing?

A) 100%
B) Between 50% to 75% depending on aircraft design.
C) The effectiveness of reverse thrust is dependent on aircraft velocity.
D) There will always be some forward thrust produced with engine reversers deployed.

Answer 20

A) 100%

Question 21

On large turbofan engines reverse thrust is accomplished by which of the following?

A) Reverse thrust is accomplished by pivoting a number of target type blocker doors to deflect the fan airstream forward.
B) Target doors which are mounted on the rear section of the engine nacelle open to form a clamshell behind the engine diverting fan and hot exhaust air forward.
C) A translating sleeve moves rearward to move the blocker doors into position and expose the cascade vanes. The blocker doors divert the fan air through the cascades accomplishing reverse thrust.
D) Both A and C

Answer 21

D) Both A and C

Question 22

During “BETA” operation in a turboprop aircraft, power lever position:

A) Schedules the operation of the constant speed unit.
B) Controls both blade angle and fuel flow (BETA plus power range.
C) Determines the amount of negative torque signal fed to the constant speed unit.
D) Automatically programs the amount of oil entering the pitch lock regulator.

Answer 22

B) Controls both blade angle and fuel flow (BETA plus power range.

Question 23

A turboprop powerplant design known as Free Turbine type is one in which:

A) There are two separate shafts - one to drive the compressor section and the other to transmit power to the reduction gearbox and thus turn the propeller.
B) The reduction gearbox unit is mounted on the outside of the engine in order to isolate the turbine section.
C) Each axial stage in the compressor section is designed so as to act independently of the previous stage.
D) The compressor turbine and the accessory drive turbine are allowed to rotate in opposite directions in order to reduce gearbox vibration.

Answer 23

A) There are two separate shafts - one to drive the compressor section and the other to transmit power to the reduction gearbox and thus turn the propeller.

Question 24

In an aircraft equipped with reversing-type propellers, undesired propeller reversing in flight is prevented by the installation of which of the following devices?

A) Low pitch synchro-transducers.
B) A high pitch bias actuator and associated blade angle detector.
C) A high pitch governor.
D) Low Pitch stops

Answer 24

D) Low Pitch stops

Question 25

In reference to a turboprop, constant speed operation is achieved by:

A) Using the exhaust air exiting from the power section to drive the power section.
B) Using a series of reduction gears to reduce the turbofan speed to approximately 2000 RPM.
C) Bringing the condition levers to the appropriate setting for the phase of flight.
D) Matching the propeller load to the gas power produced.

Answer 25

D) Matching the propeller load to the gas power produced.

Question 26

What is the main function of an Electronic Engine Control (EEC) or and Electronic Control Unit (ECU)?

A) To act in a fuel metering capacity to provide accurate fuel flow information to the cockpit engine gauges.
B) To provide accurate power or thrust information to the engine power gauges in the cockpit.
C) To regulate engine fuel flow to to maintain specific power settings as flight and environmental conditions change.
D) In fly by wire designed aircraft to transmit the desired power or thrust from the throttle quadrant to the fuel control unit on the engines.

Answer 26

C) To regulate engine fuel flow to to maintain specific power settings as flight and environmental conditions change.

Question 27

APU’s on aircraft are generally used for:

1) Generation of electrical power.
2) Heating/Air-conditioning of the aircraft on the ground.
3) Hydraulic system operation when the aircraft is on the ground.
4) Starting jet engines.
5) Aircraft anti-ice systems on the ground.

A) 1, 2, 5.
B) 1, 3, 5.
C) 2, 4, 5.
D) 1, 2, 4.

Answer 27

D) 1, 2, 4.

Question 28

The flex temperature for a gas turbine engine refers to:

A) The maximum operating temperature limit for maximum continuous power.
B) The maximum operating temperature limit for compressor turbine section of the engine.
C) The ambient air minimum starting temperature for the engine.
D) The assumed temperature used in calculating the reduced thrust settings for takeoff.

Answer 28

D) The assumed temperature used in calculating the reduced thrust settings for takeoff.

Question 29

What is the purpose of assumed temperature or de-rated takeoffs?

A) They reduce fuel consumption.
B) They increase passenger comfort by slowing acceleration.
C) They reduce engine noise for certain noise abatement procedures.
D) They reduce engine wear.

Answer 29

D) They reduce engine wear.

Question 30

In a turbojet aircraft, how does switching engine bleed air valves off for departure provide better takeoff performance?

A) No bleed air allows for the pressurization outflow valves to close reducing drag.
B) This only applies to aircraft that use bleed air for wing anti ice.
C) Having bleed air valves closed allows the engines to produce greater thrust.
D) Switching bleed air off moves the engine compressor blades to higher compression levels.

Answer 30

C) Having bleed air valves closed allows the engines to produce greater thrust.