M15.14 Engine Indication Systems

Question 1

What is the purpose of exhaust gas temperature (EGT) indication in gas turbine engines?

Answer 1

To monitor high temperatures and prevent thermal damage

Question 2

Where is the highest temperature in a gas turbine engine typically found?

Answer 2

Directly behind the combustion chamber, called the Turbine Inlet Temperature (TIT)

Question 3

What is the typical range for maximum EGT indications?

Answer 3

• 600 °C to 900 °C
• 1100 °F to 1650 °F

Question 4

List the relative temperatures used to monitor exhaust gases entering the turbine.

Answer 4

• Exhaust Gas Temperature (EGT)
• Turbine Inlet Temperature (TIT)
• Turbine Gas Temperature (TGT)
• Interstage Turbine Temperature (ITT)
• Turbine Outlet Temperature (TOT)

Question 5

What do temperature thermocouples measure in a gas turbine engine?

Answer 5

They provide a relative indication of the temperature at the turbine discharge

Question 6

What does the EGT indicator in the flight deck show?

Answer 6

The average temperature measured by individual thermocouples

Question 7

What is the function of the TIT indicating system?

Answer 7

To provide a visual indication of the temperature of gases entering the turbine

Question 8

How many thermocouples can be used in a TIT indicating system?

Answer 8

Numerous thermocouples can be used

Question 9

What is the role of the over temperature warning light in a TIT indicating system?

Answer 9

It illuminates when the TIT reaches a predetermined limit

Question 10

How are engine indications categorized?

Answer 10

• Performance indications
• System indications
• Engine trend monitoring

Question 11

What are performance indications used for?

Answer 11

To monitor engine performance and limits, and set thrust for flight phases

Question 12

What do system indications monitor?

Answer 12

The operation of engine systems such as oil or fuel systems

Question 13

What does engine trend monitoring do?

Answer 13

Detects engine problems at an early stage using recorded engine parameters

Question 14

What is the Engine Pressure Ratio (EPR)?

Answer 14

A pressure indicator relating the power developed by the engine

Question 15

How is EPR calculated?

Answer 15

By comparing the engine turbine discharge pressure to the ram air pressure at the engine inlet

Question 16

What does the flexible take-off (FLEX) thrust setting do?

Answer 16

Uses an assumed temperature thrust reduction to preserve engine wear

Question 17

What is the primary function of the oil pressure indicator?

Answer 17

To monitor engine oil pump discharge pressure

Question 18

What are the two main types of oil pressure transmitters?

Answer 18

• Bourdon Tube type
• Strain Gauge type

Question 19

How does a Bourdon tube work?

Answer 19

Changes shape under pressure, causing an indicator needle to deflect

Question 20

What is the purpose of a low oil pressure switch?

Answer 20

To initiate a low oil pressure warning if pressure decreases below a limit

Question 21

What does an oil temperature indicator measure?

Answer 21

The temperature of the oil as it enters the oil pressure pump

Question 22

What types of sensors are commonly used for oil temperature measurement?

Answer 22

• Resistance Temperature Detector (RTD)
• Thermocouple

Question 23

What is the function of the fuel pressure sensor?

Answer 23

To monitor fuel pressure and provide warnings of impending issues

Question 24

What can low fuel pressure indicate?

Answer 24

A potential fuel system malfunction or cavitation

Question 25

Fill in the blank: The highest temperature in a gas turbine engine is called the _______.

Answer 25

Turbine Inlet Temperature (TIT)

Question 26

True or False: Engine trend monitoring is usually shown in the flight deck.

Answer 26

False

Question 27

What does a differential pressure sensor monitor in a fuel system?

Answer 27

It monitors pump demand and warns of impending filter blockage and cavitation. ## Footnote Differential pressure sensors are critical for maintaining fuel system integrity.

Question 28

How is a warning of low fuel pressure displayed to the flight crew?

Answer 28

As a warning lamp or an Engine Indicating and Crew Alerting System (EICAS) status message. ## Footnote Early warnings help prevent fuel system malfunctions.

Question 29

What type of pressure gauge is typically used in light reciprocating engine aircraft?

Answer 29

A direct reading Bourdon tube pressure gauge. ## Footnote This gauge provides real-time fuel pressure readings.

Question 30

What does the fuel pressure gauge indicate when the auxiliary pump is switched off?

Answer 30

The pressure created by the engine-driven pump. ## Footnote This is crucial for understanding fuel delivery to the engine.

Question 31

What is the function of a differential fuel pressure gauge in larger aircraft?

Answer 31

It compares the fuel inlet pressure to the air inlet pressure at the fuel metering device. ## Footnote This comparison helps ensure optimal fuel flow.

Question 32

What types of sensors may modern aircraft use for fuel pressure measurements?

Answer 32

Solid-state types with digital output signals. ## Footnote These sensors enhance accuracy and reliability.

Question 33

What is the role of visual and audible warning devices in fuel pressure monitoring?

Answer 33

To alert the flight crew when fuel pressure falls outside the normal operating range. ## Footnote This is essential for ensuring safe operations.

Question 34

How do low fuel temperature issues get addressed in high-performance turbine aircraft?

Answer 34

With the use of a fuel heater. ## Footnote This helps prevent ice formation in the fuel system.

Question 35

What do fuel flow indicating systems provide to the flight crew?

Answer 35

The actual fuel flow to the engines and the fuel used since the engine was started. ## Footnote Monitoring these parameters aids in performance management.

Question 36

What principle do fuel flow transmitters operate on?

Answer 36

Force = Mass x Acceleration. ## Footnote This fundamental law of physics governs the measurement of fuel flow.

Question 37

What is the difference between synchronous mass flow and motorless mass flow transmitters?

Answer 37

Synchronous mass flow uses an electric motor, while motorless mass flow uses the fuel itself to generate acceleration. ## Footnote Each type has its own operational advantages.

Question 38

What does the rotor speed indication for engines express?

Answer 38

Percentage of a 100% design speed. ## Footnote This is critical for monitoring engine performance.

Question 39

What are the two types of sensors for measuring rotor speed?

Answer 39

* Variable reluctance type sensor * Tachometer generator type ## Footnote These sensors provide essential data for engine operation.

Question 40

What is the function of a variable reluctance sensor?

Answer 40

It detects changes in magnetic flux to determine rotor speed. ## Footnote This sensor is crucial for accurate speed readings.

Question 41

What does the tachometer generator produce?

Answer 41

A 3-phase AC voltage proportional to the input speed. ## Footnote This voltage is used to calculate rotor speed.

Question 42

What are the three different types of rotor speed indication displays?

Answer 42

* Clock-type scale * Moving vertical bar * Classical electromechanical indicator ## Footnote These displays show the actual N1 value and speed limits.

Question 43

What is the purpose of the engine vibration monitoring system?

Answer 43

To identify rotor imbalance and potential engine damage. ## Footnote Early detection can prevent severe malfunctions.

Question 44

What types of accelerometers are used in engine vibration sensors?

Answer 44

* Electromagnetic accelerometer * Piezoelectric-crystal type sensor ## Footnote Each type operates on different principles to measure vibration.

Question 45

What does the engine balancing system do?

Answer 45

It performs balance calculations to correct engine high vibration. ## Footnote This helps maintain engine health and performance.

Question 46

What is the purpose of a torque meter in turboshaft engines?

Answer 46

To measure the torque delivered to the rotor or propeller. ## Footnote Measuring torque is essential for performance assessments.

Question 47

What are the two types of torque meters mentioned?

Answer 47

* Electrical torque meter * Hydraulic torque meter ## Footnote Each type utilizes different mechanisms to measure torque.

Question 48

What is a critical test after engine maintenance or installation?

Answer 48

The power assurance test. ## Footnote This test ensures the engine can accelerate and decelerate properly.

Question 49

What is the initial step in the power assurance test procedure?

Answer 49

Position the aircraft in the engine run-up enclosure. ## Footnote Proper positioning is essential for safe testing.

Question 50

What should be set to off before increasing engine speed?

Answer 50

Ice and engine-bleed air switches

Question 51

How long should it take to increase the engine speed to maximum EPR?

Answer 51

30 seconds

Question 52

What should be marked on the thrust lever quadrant?

Answer 52

The position of maximum EPR

Question 53

How long should the engine be operated at maximum EPR?

Answer 53

No more than 30 seconds

Question 54

What is the next step after operating the engine at maximum EPR?

Answer 54

Slowly decrease the engine speed back to idle speed

Question 55

How quickly should the thrust lever be moved to the marked position?

Answer 55

Quickly

Question 56

What is the maximum duration for operating the engine at the marked position?

Answer 56

No more than 30 seconds

Question 57

What is the requirement for engine acceleration?

Answer 57

Must accelerate to required speed within seven seconds or less

Question 58

What is the requirement for engine deceleration to idle speed?

Answer 58

Must decelerate to idle speed in eight seconds or less

Question 59

How long should the engine be operated at minimum idle after exceeding 70% N1?

Answer 59

10 minutes

Question 60

What is the purpose of operating the engine at minimum idle for 10 minutes?

Answer 60

To decrease the engine temperature and safely shut down the engine