Module 15.14 Engine Indication Systems Flashcards
What is the exhaust gas temperature (EGT) used to monitor?
High temperatures experienced by the turbine.
Where is the exhaust gas temperature measured?
A colder location in the engine. Either between the high and low-pressure turbine or directly behind the low-pressure turbine.
Where are temperature thermocouples inserted?
At the turbine discharge.
What is used to measure exhaust gas temperature (EGT)?
Thermocouples
What does the exhaust gas temperature indicator scale range from?
0 °C to 1200 °C
What do engine indicators monitor?
Parameters of the engine and its systems.
The engine indications can be divided into what three groups?
Performance indications
System Indications
Engine trend monitoring
What are performance indications used to monitor?
The performance and the limits of the engine and to set the thrust for the different flight phases (primary indications).
What are system indications used to monitor?
The operation of engine systems such as the oil or fuel system. They also detect malfunctions quickly (secondary indications).
What does engine trend monitoring do?
Detects engine problems at an early stage.
Not usually shown in the flight deck.
What are engine parameters recorded by?
Aircraft Condition Monitoring System (ACMS).
How can engine indications be displayed?
Gauge type analogue displays and digital readouts.
Engine performance indications are located where?
Top ECAM/EICAS display.
Can thrust be measured directly?
No
What two indications give equivalent thrust value?
Fan rotational speed (N1)
Engine Pressure Ratio (EPR)
What does thermodynamic analysis check for?
Pressures and temperatures along the gas flow path.
What does mechanic-dynamic analysis check for?
Failures in the rotor system.
When does the oil consumption analysis generate an alert?
When oil consumption exceeds a certain level.
How does the Engine Pressure Ratio (EPR) indicator/gauge work?
It compares the engine turbine discharge pressure to the pressure of the ram air at the inlet of the engine.
To determine EPR, what are pressure measurements taken by?
Probes
Where are EPR probes located?
In the engine inlet and turbine exhaust.
What does an AMBER or RED line on the EPR indicator/gauge mean?
EPR for the maximum available thrust.
What does a BLUE circle on the EPR indicator/gauge mean?
EPR that corresponds to the actual throttle position.
What is the standard take-off thrust setting used on Airbus aircraft.
Flexible Take-Off (“FLEX”).
When is the TOGA (full) take-off thrust setting on Airbus aircraft used?
When taking off on a contaminated runway or if there’s performance constraints.
Why is FLEX the take-off setting used?
To preserve engine wear and life.
What does the FLEX take-off setting use?
Assumed temperature thrust reduction
What does the FLEX take-off temperature used reflect?
The thrust which would be achieved from a TOGA take-off with that outside air temperature. E.g. 40 °C.
What does the oil pressure indicator show?
Engine oil pump discharge pressure.
List the two main types of oil pressure transmitters.
Bourdon Tube type
Strain Gauge type
What warning does the pressure switch give?
Low oil pressure warning.
What is the pressure switch connected to?
Oil supply line and the oil tank vent line.
What does the pressure switch do when oil pressure decreases below the set limit?
The switch closes.
What primary component is responsible for measuring the engine oil temperature?
Oil temperature sensor.
What is the oil temperature sensor designed to do?
Respond to changes in temperature and convert this information into an electrical signal.
What is the most common temperature sensors used in aircraft engines?
Resistance Temperature Detector (RTD) or Thermocouple.
How is an oil over-temperature warning given?
Visual (warning light) and audible (warning sound or alert).
Where is the low-pressure sensor positioned?
After the low-pressure filter.
What sensor is fitted across the fuel filter?
A differential pressure sensor.
What do low-pressure sensors give a warning of?
Imminent filter blockage.
What can a filter blockage cause?
HP fuel pump cavitation.
How is a warning of low fuel pressure displayed?
Warning light or EICAS/ECAM status message.
What type of electric fuel temperature sensor is used in the main fuel tank?
Resistance type
What two indications does the fuel flow indicating system show?
Actual fuel flow to the engines.
Fuel used since the engine was started.
What calculates fuel flow and fuel used?
The FADEC system computer.
What can fuel be indicated in?
Kg, lbs, or tons.
What does the fuel flow transmitter measure?
Mass flow of fuel between the fuel control unit and fuel nozzles.
What two types of fuel flow transmitters are used as mass flow meters?
Synchronous mass flow
Motorless mass flow
What rotor does the N1 indicator display?
Low-pressure rotor
What rotor does the N2 indicator display?
High-pressure rotor
When would and N3 indication be needed?
If the engine has 3 rotors.
What are rotor speed indications expressed as?
A percentage of 100% max speed (rpm).
What are the three main parts to each rotor speed indication?
The sensor
Data transmission
Indication
What two types of sensor can measure rotor speed on engines?
Variable reluctance type
Tachometer generator type
Where is the tachometer generator type rotor speed sensor located?
On the gearbox.
List the three different types of rotor speed indication.
Clock-type scale
Moving vertical bar
Electromechanical indicator
What does the speed limit indication protect the engine against?
Overspeed (red line limit).
What does the N1 red line limit mean?
Maximum permitted rotor speed.
What do modern engines do if the engine speed exceeds the N1 red line limit?
The speed and duration is recorded and initiates a report from the engine trend monitoring.
What does an indication for engine vibration allow flight crew and maintenance to identify
Rotor imbalance
How is the indication for engine vibration given?
Units from 0 to about 6.
How many vibration sensors deliver electrical signals to a computer.
One or two.
What does the computer do to engine vibration data?
Collects and filters the data for indication and engine trend monitoring.
What is the engine vibration computer called?
Engine Vibration Monitoring Unit (EVMU).
What is used to sense engine vibrations?
Accelerometers
Where are the two vibration sensors located?
One in the compressor area and the other in the turbine area.
What two types of accelerometers are used on engines to measure vibration?
Electromagnetic accelerometer
Piezoelectric-crystal type
What is the vibration indication on modern aircraft is automatically controlled by?
The engine vibration monitoring unit.
How many vibration values are there for each engine?
One
How can engine vibration be decreased?
Fan balancing
What does the engine balancing system do?
Identifies the balance weights that are required to be removed and replaced
What are torque measuring systems called?
Torque meters
What are the two types of torque meters?
Electrical
Hydraulic
What is does the power assurance test check?
That the engine can accelerate from idle to a given Engine Pressure Ratio (EPR) value within a specific time and de-accelerate back to idle within a specific time.
How long does the engine operate at idle for during the power assurance test check?
5 minutes
What should be set to off during the power assurance test check?
Engine anti-ice and bleed air switches.
How quickly must the engine accelerate to the required speed during the power assurance test check?
7 seconds
How quickly must the engine decelerate to idle speed (N1)?
8 seconds or less.
After engine operation over 70% N1, how long must the engine be at idle for?
Minimum 10 minutes.
What are the three analysis used for engine trend monitoring?
Thermodynamic
Mechanical-dynamic
Oil consumption
What analysis is used to monitor engine vibration?
Mechanical-dynamic analysis
