14.2 Flashcards
What is the engine indicating system that is named as primary indications?
Performance Indications
What is the engine indicating system that is named as secondary indications?
System Indications
This engine indicating system monitors the performance and the limits of the engine and sets the thrust for different flight phases.
Engine Trend Monitoring
This engine indicating system monitors the operation of engine systems such as the oil or fuel system. They are also used to detect malfunctions quickly.
System Indications
This is done on the ground to detect engine problems at an early stage. It uses engine parameters that are automatically recorded by ACMS.
Engine Trend Monitoring
Where can you find the engine indications which have a combination of gauge type analog display and digital readouts?
ECAM
What variables are indicated on the engine system indicator?
Fuel uses, oil temp, oil quantity, oil pressure, nacelle temperature, engine vibration
What variables are indicated on the engine performance indicator?
EPR, EGT, N1, N2
What are the warnings and cautions displayed on the CAM engine system indications?
Low oil pressure, system exceeds a limit, oil filter clog, thrust reverser unlocked
How does the ACMS provide the recorded engine data for engine trend monitoring?
print-out from cockpit printer and ACARS
What are the 3 diff. analyses done to indicate a trend towards a limit?
Thermodynamic analysis, mechanic-dynamic analysis, oil consumption analysis
This analysis checks the pressures and temperatures along the gas flow path. It also monitors VSV, VBV, active clearance control and fuel flow.
Thermodynamic Analysis
This analysis generates an alert when the oil consumption exceeds
Oil consumption Analysis
This analysis mainly checks for failures in the rotor system such as imbalances and bearing failures by checking engine vibration and rotor speed signals.
Mechanic-dynamic Analysis
What is the N1 and N2 indications for?
for low pressure rotor and high-pressure rotor indication
What type of sensor measures rotor speed for N1 which is located on the low-pressure driveshaft?
Variable Reluctance sensor
What type of sensor measures rotor speed for N2 which is located in HP rotor AGB?
Tachometer
What speed limit indication shows the maximum permitted rotor speed?
a red line
How can you reset the exceedance indication for modern aircraft?
Automatically done with the next engine start
What does the amber line indicate for the N1 indication?
Maximum available thrust
What does the blue circle or white line indicate for the N1 indication?
Actual throttle position
It corresponds to the engine thrust as it is the ratio of the total pressure at the turbine outlet (P5) to the total pressure at the fan inlet (P2).
EPR indication
What type of sensor is used for EPR?
Pressure sensor
For earlier types of computers, what type of EPR transmitter uses electromechanical pressure transducers?
Bourdon tube
It calculates the EPR for modern engines and uses electronic pressure transducers rather than electromechanical transducers.
FADEC
What indication is necessary to monitor the high temperature in the engine exhaust to see when a limit is exceeded?
EGT indication
This temperature is directly behind the combustion chamber where the hot gas hits the high-pressure turbine.
Turbine inlet temperature
The highest temperature of the engine is directly behind the combustion chamber where the hot gas hits the high-pressure turbine. This temperature is called
Turbine Inlet Temperature
TIT can be higher that 1400° C thus it is not easy to measure. What is the possible way of measuring the TIT?
EGT is measured at colder location between the high- and low-pressure turbine. This is possible because EGT has direct relationship with TIT
What type of sensor is used for measuring the EGT?
Thermocouple
How are thermocouples connected in order to measure the average exhaust gas temperature?
thermocouples are connected in parallel
Why are thermocouples paralleled in groups in parallel junction boxes?
To make probe replacement easier
In what condition is ET allowed to exceed the amber line value (maximum EGT)?
during take-off or go around
It is a very important secondary engine indication that enables you to identify a rotor imbalance which can be the first sign of engine damage.
Vibration monitoring
What type of sensors are used for measuring the radial acceleration of the rotor system which are located in the compressor and turbine area?
Accelerometers
What are the two types of accelerometers used to measure engine vibration?
Electromagnetic accelerometer, piezoelectric-crystal type
How does electromagnetic sensor function?
it has a permanent magnet and a fixed coil, the coil moves up and down with vibration and induces an AC voltage
How does a piezoelectric crystal sensor function?
it generates a voltage when a force is applied to the crystal and presses against the base plate when the sensor is accelerated
This mode of indication measures the vibration of the N1 rotor using the forward sensor.
FAN
This mode of indication measures the vibration of the N1 rotor using the aft sensor.
Low Pressure Turbine
This mode of indication measures the vibration of the N2 rotor using the aft sensor.
N2
This mode of indication shows the unfiltered vibration from the aft sensor and is used when a rotor speed signal is not available.
BB
What sensor is used for fan balancing?
Trim balance sensor
What indications does fuel flow indicating system provides for the pilot?
Actual fuel flow to engines, fuel used
What indication shows the mass of fuel which is burned since the last engine start on ground?
Fuel used
What indication allows you to monitor the performance and economic operation of the engines?
Fuel flow indication
What type of sensor is used to generate the fuel flow and fuel used indications which measures the mass flow of fuel between the fuel control unit and the fuel nozzles?
Fuel Flow Transmitter
What system computer does the calculation for fuel flow and fuel used for modern aircrafts?
FADEC
What component measures the oil quantity for engine oil monitoring system?
Oil quantity transmitter
What unit is responsible for the measurement and display of the oil quantity?
EIU
What are the two types of oil quantity transmitter used for oil quantity indication?
Capacitance type, reed switch type
This type of oil quantity transmitter has a metal tube with a float assembly that contains permanent magnets inside and a multi switch assembly.
Reed Switch Type
What type of sensor does oil pressure indicator have that senses the pressure difference between the total oil pressure in the oil supply line and the vent pressure in the oil tank?
Oil pressure transmitter
What are the two main types of oil pressure transmitter?
Bourdon tube type, strain gage type
What indications are provided in a low oil pressure situation?
Warning message and acoustic warning in cockpit
What is the sequence of events that will occur in case of low oil pressure?
Low oil pressure switch closes, signal is sent to FC and warning message is displayed in the cockpit
What are the 2 types of oil temperature sensors used for oil temp. indication?
Thermocouple, Thermistor
This element catches larger particles which are 0.015mm in size.
The problem with this element is that it is not changed very often and each inspection takes time.
Scavenge oil filter
This is used for oil contamination monitoring where it catches metal particles that are attracted to its magnet. It can be easily removed and checked.
Magnetic chip detector
How does the magnetic chip detector function?
the resistance decreases when particles connect the 2 chip detector magnets, when the resistance gets below the limit, the ECU sends maintenance message to PFR
