M15.14 Engine Indication Systems Flashcards
What is the purpose of exhaust gas temperature (EGT) indication in gas turbine engines?
To monitor high temperatures and prevent thermal damage
Where is the highest temperature in a gas turbine engine typically found?
Directly behind the combustion chamber, called the Turbine Inlet Temperature (TIT)
What is the typical range for maximum EGT indications?
- 600 °C to 900 °C
- 1100 °F to 1650 °F
List the relative temperatures used to monitor exhaust gases entering the turbine.
- Exhaust Gas Temperature (EGT)
- Turbine Inlet Temperature (TIT)
- Turbine Gas Temperature (TGT)
- Interstage Turbine Temperature (ITT)
- Turbine Outlet Temperature (TOT)
What do temperature thermocouples measure in a gas turbine engine?
They provide a relative indication of the temperature at the turbine discharge
What does the EGT indicator in the flight deck show?
The average temperature measured by individual thermocouples
What is the function of the TIT indicating system?
To provide a visual indication of the temperature of gases entering the turbine
How many thermocouples can be used in a TIT indicating system?
Numerous thermocouples can be used
What is the role of the over temperature warning light in a TIT indicating system?
It illuminates when the TIT reaches a predetermined limit
How are engine indications categorized?
- Performance indications
- System indications
- Engine trend monitoring
What are performance indications used for?
To monitor engine performance and limits, and set thrust for flight phases
What do system indications monitor?
The operation of engine systems such as oil or fuel systems
What does engine trend monitoring do?
Detects engine problems at an early stage using recorded engine parameters
What is the Engine Pressure Ratio (EPR)?
A pressure indicator relating the power developed by the engine
How is EPR calculated?
By comparing the engine turbine discharge pressure to the ram air pressure at the engine inlet
What does the flexible take-off (FLEX) thrust setting do?
Uses an assumed temperature thrust reduction to preserve engine wear
What is the primary function of the oil pressure indicator?
To monitor engine oil pump discharge pressure
What are the two main types of oil pressure transmitters?
- Bourdon Tube type
- Strain Gauge type
How does a Bourdon tube work?
Changes shape under pressure, causing an indicator needle to deflect
What is the purpose of a low oil pressure switch?
To initiate a low oil pressure warning if pressure decreases below a limit
What does an oil temperature indicator measure?
The temperature of the oil as it enters the oil pressure pump
What types of sensors are commonly used for oil temperature measurement?
- Resistance Temperature Detector (RTD)
- Thermocouple
What is the function of the fuel pressure sensor?
To monitor fuel pressure and provide warnings of impending issues
What can low fuel pressure indicate?
A potential fuel system malfunction or cavitation
Fill in the blank: The highest temperature in a gas turbine engine is called the _______.
Turbine Inlet Temperature (TIT)
True or False: Engine trend monitoring is usually shown in the flight deck.
False
What does a differential pressure sensor monitor in a fuel system?
It monitors pump demand and warns of impending filter blockage and cavitation.
Differential pressure sensors are critical for maintaining fuel system integrity.
How is a warning of low fuel pressure displayed to the flight crew?
As a warning lamp or an Engine Indicating and Crew Alerting System (EICAS) status message.
Early warnings help prevent fuel system malfunctions.
What type of pressure gauge is typically used in light reciprocating engine aircraft?
A direct reading Bourdon tube pressure gauge.
This gauge provides real-time fuel pressure readings.
What does the fuel pressure gauge indicate when the auxiliary pump is switched off?
The pressure created by the engine-driven pump.
This is crucial for understanding fuel delivery to the engine.
What is the function of a differential fuel pressure gauge in larger aircraft?
It compares the fuel inlet pressure to the air inlet pressure at the fuel metering device.
This comparison helps ensure optimal fuel flow.
What types of sensors may modern aircraft use for fuel pressure measurements?
Solid-state types with digital output signals.
These sensors enhance accuracy and reliability.
What is the role of visual and audible warning devices in fuel pressure monitoring?
To alert the flight crew when fuel pressure falls outside the normal operating range.
This is essential for ensuring safe operations.
How do low fuel temperature issues get addressed in high-performance turbine aircraft?
With the use of a fuel heater.
This helps prevent ice formation in the fuel system.
What do fuel flow indicating systems provide to the flight crew?
The actual fuel flow to the engines and the fuel used since the engine was started.
Monitoring these parameters aids in performance management.
What principle do fuel flow transmitters operate on?
Force = Mass x Acceleration.
This fundamental law of physics governs the measurement of fuel flow.
What is the difference between synchronous mass flow and motorless mass flow transmitters?
Synchronous mass flow uses an electric motor, while motorless mass flow uses the fuel itself to generate acceleration.
Each type has its own operational advantages.
What does the rotor speed indication for engines express?
Percentage of a 100% design speed.
This is critical for monitoring engine performance.
What are the two types of sensors for measuring rotor speed?
- Variable reluctance type sensor
- Tachometer generator type
These sensors provide essential data for engine operation.
What is the function of a variable reluctance sensor?
It detects changes in magnetic flux to determine rotor speed.
This sensor is crucial for accurate speed readings.
What does the tachometer generator produce?
A 3-phase AC voltage proportional to the input speed.
This voltage is used to calculate rotor speed.
What are the three different types of rotor speed indication displays?
- Clock-type scale
- Moving vertical bar
- Classical electromechanical indicator
These displays show the actual N1 value and speed limits.
What is the purpose of the engine vibration monitoring system?
To identify rotor imbalance and potential engine damage.
Early detection can prevent severe malfunctions.
What types of accelerometers are used in engine vibration sensors?
- Electromagnetic accelerometer
- Piezoelectric-crystal type sensor
Each type operates on different principles to measure vibration.
What does the engine balancing system do?
It performs balance calculations to correct engine high vibration.
This helps maintain engine health and performance.
What is the purpose of a torque meter in turboshaft engines?
To measure the torque delivered to the rotor or propeller.
Measuring torque is essential for performance assessments.
What are the two types of torque meters mentioned?
- Electrical torque meter
- Hydraulic torque meter
Each type utilizes different mechanisms to measure torque.
What is a critical test after engine maintenance or installation?
The power assurance test.
This test ensures the engine can accelerate and decelerate properly.
What is the initial step in the power assurance test procedure?
Position the aircraft in the engine run-up enclosure.
Proper positioning is essential for safe testing.
What should be set to off before increasing engine speed?
Ice and engine-bleed air switches
How long should it take to increase the engine speed to maximum EPR?
30 seconds
What should be marked on the thrust lever quadrant?
The position of maximum EPR
How long should the engine be operated at maximum EPR?
No more than 30 seconds
What is the next step after operating the engine at maximum EPR?
Slowly decrease the engine speed back to idle speed
How quickly should the thrust lever be moved to the marked position?
Quickly
What is the maximum duration for operating the engine at the marked position?
No more than 30 seconds
What is the requirement for engine acceleration?
Must accelerate to required speed within seven seconds or less
What is the requirement for engine deceleration to idle speed?
Must decelerate to idle speed in eight seconds or less
How long should the engine be operated at minimum idle after exceeding 70% N1?
10 minutes
What is the purpose of operating the engine at minimum idle for 10 minutes?
To decrease the engine temperature and safely shut down the engine
