15.14 Engine Indication Systems Flashcards
What are the 3 types of engine indication?
- Performance indications (primary)
- System indications (secondary)
- Engine trend monitoring (not usually shown)
What is the purpose of the engine performance indications?
Used to monitor performance and limits and set the thrust for different flight phases
What is the purpose of the engine system indications?
To monitor the operation of the engine systems such as fuel or oil. These are used to detect malfunctions quickly.
What is the purpose of the engine trend monitoring?
It is done on the ground to check engine problems at an early stage. It uses parameters automatically recorded by ACMS
What does ACMS stand for?
Aircraft Condition and Monitoring System
What type of engine display does Airbus ECAM use?
A combination of gauge type analogue display and digital readouts
What type of engine display does Boeing EICAS use?
Analogue indications with vertical bars
Where are Engine performance indications usually shown?
Always shown on the top screen of the ECAM or EICAS
What is the rotational speed of the fan also known as?
N1 speed
What is the engine pressure ratio (EPR)?
The measurement of the total pressure at the exhaust compared to the total pressure at the fan inlet
What is the EGT?
Exhaust gas temperature
What can be the cause of engine vibration?
Damaged blades or bearings
How can the engine nacelle increase in temperature?
If there is a hot air leak in the nacelle
What warnings would appear on the ECAM/EICAS?
- exceeding limits
- unlocked thrust reversers
- low pressure in oil
- clogged filters
What is engine trend monitoring?
The monitoring of an engines performance during flight to and to monitor engine problems
How is the engine trend monitoring system recorded?
By the Aircraft Condition Monitoring System (ACMS) on the MCDU which can be printed and also ACARS (Aircraft communication and reporting system) via data link to the ground
How are the engine rotor speed indications always presented?
As a percentage of a 100% design speed
What is the N1 indication for?
The LP rotor speed
What is the N2 indication for?
HP rotor speed
What does EPR stand for?
Engine pressure ratio
How is the engine pressure ratio calculated?
The ratio of the total pressure at the exhaust compared to the total pressure at the fan inlet
What is the purpose of the EGT indication?
It is used to monitor the exhaust gas temperature incase limits are exceeded. It is directly related to the TIT (Turbine inlet temperature) just after combustion
What can the temperatures be as high as when they first enter the turbine section?
1400°C
What are the three types of EGT indication that can be present in the cockpit?
- a clock-type scale
- a moving vertical bar
- a classical electromechanical indicator
What does a red line indicate on the EGT indicator?
The temperature never to be exceeded
What is the amber line on an EGT indicator?
The maximum temperature that can only be exceeded for a short while at maximum thrust setting (such as takeoff/go-around)
What is EGT measured in?
Degrees Celsius
What is the purpose of engine vibration monitoring?
It enables identification of rotor imbalances which can be the first sign of engine damage
What does EVMU stand for?
Engine vibration monitoring unit
What are the main parts of the EVMU?
- indication (0-6 units)
- 1 or 2 sensors sending signals to a computer
Where are the two vibration monitoring sensors located?
One in the compressor area, near the N1 rotor shaft and one in the turbine area
What indication is seen in the cockpit if the vibration reaches a critical level?
The indication starts pulsing for the pilot to react
What is the fuel flow indications measured in?
Kg or tons
What are the two fuel indications in the cockpit?
- Actual fuel flow
- Fuel used since engine start
The fuel indications, has what secondary use?
It provides redundancy indication for the remaining fuel quantity
When is the fuel used indication reset to 0?
Automatically; when the master switch is set to ON and the aircraft is on the ground
What is the purpose of the fuel flow transmitter?
It measures the fuel mass flow between the control unit and the fuel nozzles
What basic physics law do all fuel flow transmitters use?
Force = mass x acceleration
They measure the force applied by the mass of fuel
How does an older fuel flow transmitter accelerate the fuel?
By using an impeller driven by an electric motor
How does a modern fuel flow transmitter accelerate the fuel?
It uses the fuel to drive an impeller
How does the FADEC system calculate the fuel flow from the fuel flow transmitter?
It measures the time between the pulses of fuel flowing which is proportional to the mass flow
What is the EIU?
Engine Interface Unit
Where is the oil quantity transmitter usually installed?
At the top of the oil tank
What are the two types of oil quantity transmitter used?
- capacitance type
- reed switch type
What are the two types of pressure transmitter sensors used for oil indication?
- Bourdon tube type
- Strain gauge type
What is the low oil pressure switch for?
It indicates a low oil pressure warning in the cockpit
It is ALWAYS accompanied by an acoustic warning
What are the two types of oil temperature sensors?
- Thermistor type
- Thermocouple
What does SOAP stand for?
Spectrometric Oil Analysis Program
What is the SOAP process used for?
It is used to find internal wear of lubricated engine components
What size of contaminated oil particles can the SOAP process discover?
0.001m - 0.02mm
What size particles can the scavenge systems catch?
Particles larger than 0.015mm
What is the advantage of using magnetic chip detectors?
Easier and less time consuming method of oil contamination indication
