ENGINE INDICATION Flashcards
What 3 groups are engine indications divided into?
Performance (monitor limits, set thrust)
System (e.g oil and fuel systems, detect malfunctions quickly)
Engine trend (done on ground to detect engine problems early)
What type displays show engine indications?
Analogue and digital.
Where are Engine performance indications always shown?
At the top.
What 2 indications can give engine thrust?
N1 speed
Engine pressure ratio (EPR)
What is EGT?
Exhaust gas temperature.
How is the engine performance data usually transmitted to indicators?
Electrically, measured by specific sensors or probes.
What system does engine trend monitoring use information from?
ACMS (aircraft condition monitoring system)
What 3 different types of ananlyses are done for engine trend monitoring?
- Thermodynamic (measures pressures and temps of gas flow path)
- Mechanic-dynamic (checks vibration and rotor speed signals)
- Oil consumption (alert when oil consumption exceeds certain limit)
How are engine rotor speeds always expressed?
As a percentage of 100% design speed.
What is the engine pressure ratio?
Ratio of total pressure at turbine outlet to total pressure at fan inlet.
What is TIT?
Turbine inlet temperature (highest temps in engine)
Can be higher than 1400 Celsius.
Where is EGT measured from?
Directly between HP and LP turbine or behind LP turbine. (Maximum can be between 600 and 900 Celsius)
Too hot in the TIT.
What is the amber lime on EGT indications?
Max EGT for maximum continuous thrust.
Only allowed to exceed for take off or go around thrust.
Where is oil pressure information transmitted?
Sent from the oil pressure transmission to the engine interface unit
What are the two types of oil transmitter?
- bourdon tune
- strain gauge
Low oil pressure warnings are always accompanied by what type of warning?
An acoustic warning.
Where can the oil temperature sensor be located?
Scavenge System - senses hot oil upstream of oil cooler
Pressure system - senses temp of cooled oil
What is the spectrometric oil analysis program? SOAP
Find internal wear of lubricated engine components
Find parts that filter can pick up ranging from sizes 0.01 - 0.02mm
Where are SOAP oil samples taken from?
Oil tank on a regular basis
What size particles are the filter elements in an oil system able to pick up?
Sizes above 0.015mm
What is the issue with filters in oils systems?
It is not changed often and inspections take time.
How can magnetic chip detectors be inspected?
Manually by removing
Automatically on modern aircraft and removed when necessary.
How does the magnetic chip detector work?
Resistance will decrease when particles connect with the detector. Once below a value the ECU sends maintenance message.
What units usually show the level of vibration?
0-6
What is EVMU?
Engine vibration monitoring unit.
What are engine vibration sensors made up of?
Accelerometers that measure the radial acceleration of the rotor system.
What is the BB vibration sensor?
Broad band, unfiltered vibration signal from aft sensor.
Used when rotor signals not available
What happens when a vibration level reaches a critical value?
Vibration indication starts pulsing.
What does the fuel flow transmitter measure?
Flow of fuel between fuel control unit and the fuel nozzles.
Based on; force = mass x acceleration
What position transducers in fuel flow transmitters measure the turbine angle?
Synchro or RVDT.
Why do modern fuel flow transmitters not need an electric motor with a power supply?
Use the fuel itself to generate acceleration.
