Turbine 2 - Week 6
What is the pour point of a liquid?
The highest temperature at which it remains pourable
The lowest temperature at which it remains pourable
The average temperature at which it remains pourable
The temperature at which it changes color
What is volatility?
The tendency of a substance to freeze at low temperatures
The rate of combustion at high temperatures
The evaporation loss of oil and additives at high temperatures
The ability of a substance to resist oxidation
What is flash point?
The temperature at which it spontaneously ignites
The lowest temperature at which it sustains combustion
A general indication of the flammability or combustibility of the liquid
The temperature at which it freezes
What improvement did MIL-L (PRF)-23699 HTS bring compared to 2nd Gen (Type II) MIL-L (PRF)-23699 synthetic oil?
Improved fuel efficiency
Better thermal stability, viscosity stats and better anti-wear protection and resistance to oxidation than 7808 (Type 1) fluids
Higher viscosity stats
Better low-temperature performance
What is the purpose of the oil scupper?
It turns on a warning light in the Flight Deck to warn the pilot of all contamination
Is used to drain away oil while servicing to prevent a possible fire hazard
It has a magnet to inspect the oil for ferrous metal contaminants
Is used to filter the oil
What is the VISCOSITY of engine oil?
The measure of a fluid's ability to conduct heat
The measure of a fluid's internal resistance to flow, the resistance to being deformed
The measure of a fluid's density
The measure of a fluid's ability to dissolve other substances
What is the abbreviation ATA?
Air Travel Administration
Aviation Technical Association
Air Transportation Authority
Aerospace Technology Agency
Under what ATA Chapter will the OIL System be found?
Ata 24
77
79
78
When must oil samples be collected from the engine?
Immediately after engine shutdown
Within 1 to 3 minutes after engine shutdown
Within 5 to 30 minutes after engine shutdown
At least 1 hour after engine shutdown
What is the function of the engine Oil system?
To remove heat from the engine
To lubricate gears and bearings
To remove debris from the oil
All of the above
Select the answer that best describes a Dry Sump oil system
Is never used on large airliner engines
Does not require an oil filter
Has an external oil tank for oil storage
All the oil is stored inside the engine
Select the answer that best describes an Oil Filter bypass condition
The pressure drop across the filter is too high
The oil filter is in perfect and normal condition
There will be a Green pop-out indicator at the filter
The Oil system quantity is low, you must add some oil to top-up quantity
Where would you typically find a Magnetic Chip Detector?
In the pressure oil circuit
In the return (scavenge) oil circuit
In the Flight Deck for pilot’s to do a fast check on engine oil condition
Attached to the Oil dip stick
According to CAR Standard 625, Appendix C (7), what maintenance requirement does it impose on commercially operated turbine engines?
Overhaul must be performed annually
Maintenance intervals are determined by the aircraft owner
Maintenance is optional, based on operator discretion
Any commercially operated turbine engine must be maintained and overhauled at intervals recommended by engine manufacturer
Cycles (for a Turbine Engine): How is one complete cycle traditionally defined??
An engine start and run only
An engine start, run, and shut-down
An engine start and shutdown only
An engine run and shutdown only at idle power
Which of the following best describes TSO (Time Since Overhaul)?
Total Shutdown Operations
Time Since Onset
Total Service Operations
Hours of engine operation since the engine underwent a complete overhaul
Which of the following best describes TBO (TIME BETWEEN OVERHAUL)?
Hours of engine operation between mandatory engine overhaul
Total Breakdown Offset
Time Between Onsets
Total Burnout Operations
According to FAA definitions, what constitutes a major overhaul of an aircraft engine?
Cleaning and lubrication of engine components
Replacement of damaged external parts
Partial disassembly and inspection of critical components
Complete disassembly of engine, inspection, repairs as necessary, reassembly, testing, and approval for return to service within the fits and limits specified by the manufacturer’s overhaul data
In regards to engine trend monitoring, what does the term "HOURS" refer to?
Hours since last inspection
Hours since last overhaul
Actual hours the engine has been run/operated
Total hours the aircraft has been in service
What does "Life Limited Cycle Time," also known as "Hard Time," signify in aviation maintenance?
The maximum allowable time between overhauls
The total accumulated hours since the last overhaul
Purely a time-based standard that calls for mandatory replacement of a unit and end of units service life, TBO or TSO are not applicable
The maximum operational time before a scheduled maintenance event
What does a "Hot Section Inspection" in the context of a gas turbine engine typically involve?
A hot section refers to the portion of a gas turbine engine that operates at a high temperature (includes the combustion, turbine and exhaust sections)
Inspection of the engine's electrical components
Examination of the engine's cooling system components
Inspection of the engine at elevated ambient temperatures
What is TTSN (Total Time Since New), and how is it typically used?
The total time since the last major overhaul
The total time since the engine's last inspection
Engine hours running since it was new. Used for calculating Life Ltd Cycle Time
The total time the aircraft has been in service, excluding engine hours
How is aircraft engine vibration monitored?
Visual inspections during maintenance
Listening for abnormal sounds during flight
Utilizing Engine Condition Trend Monitoring (ECTM)
Measuring exhaust gas temperature
What is the primary indication provided by vibration monitoring?
Component imbalance or looseness of parts installed on the engine
Detection of fuel system irregularities
Measurement of oil viscosity changes
Identification of exhaust system leaks
How is engine vibration typically sensed in aircraft engines?
Through pressure sensors in the combustion chamber
Via acoustic microphones placed around the engine
Using one or two pick-ups called transducers (or accelerometers)
Through temperature probes on critical engine components
How do Piezo-electric Transducers monitor engine vibration?
They convert vibration into a proportional voltage, voltage is sent to a signal conditioner that amplifies it for instrument display
They emit ultrasonic signals during vibration
They generate heat in response to vibration
They measure changes in air pressure caused by vibration
What are identified as the typical sources of vibration in turbine engines?
Combustion chambers and fuel injectors
N1, N2, N3 rotors and AGB components
Exhaust nozzles and thrust reversers
Ignition systems and spark plugs
What are the primary factors responsible for causing vibration in turbine engines?
Imbalanced rotors, internal damage or worn bearings and parts
Variations in fuel quality and combustion efficiency
Changes in ambient temperature and humidity
Atmospheric conditions and air turbulence
Why are the high-frequency vibrations of turbine engines considered undetectable by visual means?
They occur inside the combustion chamber
They are masked by the engine's external casing
They are too faint to be observed with the naked eye
They are only visible under specialized UV light
S.O.A.P. SPECTROMETRIC OIL ANALYSIS PROGRAM is an important process for what?
Turbine engine condition monitoring
Analyzing combustion stability in the engine
Evaluating the exhaust emissions of the engine
Monitoring fuel efficiency in turbine engines
OIL SAMPLES are collected for analysis at regular time intervals. For example, every ___ hours of engine operation
100 hours
50
20
10
When should S.O.A.P. (Spectrometric Oil Analysis Program) oil samples be collected from the engine?
Immediately after engine shutdown
Within 1 to 3 hours of engine shutdown
Within 5 to 30 minutes of engine shutdown
Within 5 to 30 minutes of engine shutdown
Why must the oil sample be captured after certain period of time?
This ensures the oil sample has captured suspended particles in the oil before they settle
To avoid contamination from external environmental factors
To ensure accurate measurement of oil viscosity
To prevent oxidation of the oil due to prolonged exposure
Where would you typically find information regarding Airworthiness Limitations?
ATA Chapter 4 of the applicable Maintenance Manual (MM)
ATA Chapter 2 of the Aircraft Operations Manual
ATA Chapter 6 of the Structural Repair Manual (SRM)
ATA Chapter 8 of the Illustrated Parts Catalog (IPC)
ATA Chapter 4 includes what type of limitations?
Limitations consist of useage limits on various components within the engine that must be replaced when either the cycle limit or time limit has been reached
Limitations consist of useage limits on various components within the airframe that must be replaced when either the cycle limit or time limit has been reached
Limitations consist of useage limits on various components within the exhaust that must be replaced when either the cycle limit or time limit has been reached
Limitations consist of useage limits on various components within the fuselage that must be replaced when either the cycle limit or time limit has been reached
What does the pressure system in the dry sump system do?
Supplies clean, filtered oil to parts of the engine that experience metal-to-metal contact such as gears and bearings
Regulates fuel flow to the combustion chamber
Reduces friction in the transmission
Cools the engine components
What does the scavenge system in the dry sump system do?
Adds additional oil to the engine
Filters contaminants from the oil
Pressurizes the oil for improved lubrication
Returns the oil back to the external OIL storage tank
Why must one be careful when opening an oil tank after engine shut down?
Tank may still be pressurized and need time for pressure to bleed down
Ensure the tank is completely empty before opening
Open the tank quickly to release any pressure
Wear protective gloves to handle the tank
What is wet-sump system?
Oil is kept inside the eng in the sump (aka oil pan), usually located at bottom of the engine, oil is picked up by suction from the oil pump.
Oil is stored in an external reservoir
Oil is pressurized directly into the combustion chamber
Oil is cooled by a separate cooling system
What is dry-sump system?
Oil is gravity fed to bottom of engine, scavenge pump(s) then pump the oil back to external oil tank
Oil is pressurized directly into the combustion chamber
Oil is cooled by a separate cooling system
Oil is stored in an external reservoir
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