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Lubrication Systems

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amaretariku's version from 2017-10-20 11:47

Section 1

Question Answer
What will be the result of operating an engine in extremely high temperatures using a lubricant recommended by the manufacturer for a much lower temperature?The oil pressure will be lower than normal
Oil tank fillers on reciprocating engines are marked with the word"oil," in accordance with 14 CFR part 23
High tooth pressures and high rubbing velocities, such as occur with spur-type gears, require the use ofan EP lubricant
The engine oil temperature regulator is usually located between which of the following on a dry sump reciprocating engine?The scavenger pump outlet and the oil storage tank
Where is the oil of a dry sump reciprocating engine exposed to the temperature control valve sensing unit?Oil cooler inlet
An oil tank having a capacity of 5 gallons must have an expansion space of2 quarts
In order to relieve excessive pump pressure in an engine's internal oil system, most engines are equipped with arelief valve
What is the primary purpose of the hopper located in the oil supply tank of some dry sump engine installations?To reduce the time required to warm the oil to operating temperatures
What will result if an oil filter becomes completely blocked?Oil will flow at the normal rate through the system
The recommended aircraft engine lubricants aremineral or synthetic based
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Section 2

Question Answer
Which type valve prevents oil from entering the main accessory case when the engine is not running?Check
The vent line connecting the oil supply tank and the engine in some dry sump engine installations permitsthe oil tank to be vented through the normal engine vent
Oil picks up the most heat from which of the following turbine engine components?Turbine bearing
The pumping capacity of the scavenger pump in a dry sump aircraft engine's lubrication systemis greater than the capacity of the oil supply pump
Why is an aircraft reciprocating engine oil tank on a dry sump lubrication system equipped with a vent line?To prevent pressure buildup in the oil tank
What prevents pressure within the lubricating oil tank from rising above or falling below ambient pressure (reciprocating engine)?Oil tank vent
If the oil in the oil cooler core and annular jacket becomes congealed, what unit prevents damage to the cooler?Surge protection valve
What advantage do mineral base lubricants have over vegetable oil base lubricants when used in aircraft engines?Chemical stability
Which of the following has an effect on the viscosity of lubricating oil?Temperature
Upon what quality or characteristic of a lubricating oil is its viscosity index based?Its rate of change in viscosity with temperature change
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Section 3

Question Answer
Which of the following bearing types must be continuously lubricated by pressure oil?Plain
Where is the oil temperature bulb located on a dry sump reciprocating engine?Oil inlet line
The viscosity of a liquid is a measure of itsresistance to flow
Why are fixed orifice nozzles used in the lubrication system of gas turbine engines?To provide a relatively constant oil flow to the main bearings at all engine speeds
In a reciprocating engine, oil is directed from the pressure relief valve to the inlet side of thepressure pump
The type of oil pumps most commonly used on turbine engines are classified aspositive displacement
How is the oil collected by the piston oil ring returned to the crankcase?Through holes drilled in the piston oil ring grove
What is the purpose of the last chance oil filters?To filter the oil immediately before it enters the main bearings
As a general rule, a small amount of small fuzzy particles or gray metallic paste on a turbine engine magnetic chip detectoris considered to be the result of normal wear
What is the primary purpose of the oil breather pressurization system that is used on turbine engines?Provides a proper oil spray pattern from the main bearing oil jets
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Section 4

Question Answer
What type of oil system is usually found on turbine engines?Dry sump, pressure, and spray
The purpose of the flow control valve in a reciprocating engine oil system is todirect oil through or around the oil cooler
The primary source of oil contamination in a normally operating reciprocating engine iscombustion deposits due to combustion chamber blow-by and oil migration on the cylinder walls
Oil accumulation in the cylinders of an inverted in-line engine and in the lower cylinders of a radial engine is normally reduced or prevented byextended cylinder skirts
The time in seconds required for exactly 60 cubic centimeters of oil to flow through an accurately calibrated orifice at a specific temperature is recorded as a measurement of the oil'sviscosity
Which of these characteristics is desirable in turbine engine oil?High flash point
In order to maintain a constant oil pressure as the clearances between the moving parts of an engine increase through normal wear, the supply pump outputremains relatively constant (at a given RPM) with less oil being returned to the pump inlet by the relief valve
In an axial-flow turbine engine, compressor bleed air is sometimes used to aid in cooling theturbine, vanes, blades, and bearings
How are the teeth of the gears in the accessory section of an engine normally lubricated?By splashed or sprayed oil
From the following, identify the factor that has the least effect on the oil consumption of a specific engine.Mechanical efficiency
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Section 5

Question Answer
As a general rule, the mixture setting on a reciprocating engine operating at or near takeoff power that provides the best cooling isFULL RICH
Which of the following factors helps determine the proper grade of oil to use in a particular engine?Operating speeds of bearings
(1) Gas turbine and reciprocating engine oils can be mixed or used interchangeably.(2) Most gas turbine engine oils are synthetic.Only No. 2 is true
Some larger reciprocating engines use a compensating oil pressure relief valve toprovide a high engine oil pressure when the oil is cold and automatically lower the oil pressure when the oil warms up
Excessive oil is prevented from accumulating on the cylinder walls of a reciprocating engine byoil control rings on the pistons
In which of the following situations will the oil cooler automatic bypass valve be open the greatest amount?Engine oil below normal operating temperature
The main oil filters strain the oil at which point in the system?Just as it leaves the pressure pump
Under which of the following conditions is the oil cooler flow control valve open on a reciprocating engine?When the temperature of the oil returning from the engine is to low
What determines the minimum particle size which will be excluded or filtered by a cuno-type (stacked disc, edge filtration) filter?The spacer thickness
Lubricating oils with high viscosity index ratings are oilsin which the viscosity does not vary much with temperature change
(1) Fuel may be used to cool oil in gas turbine engines.(2) Ram air may be used to cool oil in gas turbine engines.both No. 1 and No. 2 are true
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Section 6

Question Answer
In addition to lubricating (reducing friction between moving parts), engine oil performs what functions?1. Cools.2. Seals.3. Cleans.4. Prevents corrosion.5. Cushions impact (shock) loads.1, 2, 3, 4, 5
A drop in oil pressure may be caused byforeign material under the relief valve
What will happen to the return oil if the oil line between the scavenger pump and the oil cooler separates?the return oil will be pumped overboard
At cruise RPM, some oil will flow through the relief valve of a gear-type engine oil pump. This is normal as the relief valve is set at a pressure which islower than the pressure pump capabilities
Where are sludge chambers, when used in aircraft engine lubrication systems, usually located?In the crankshaft throws
Compared to reciprocating engine oils, the types of oils used in turbine engineshave less tendency to preduce lacquer or coke
If a full-flow oil filter is used on an aircraft engine, and the filter becomes completely clogged, thebypass valve will open and the oil pump will supply unfiltered oil to the engine
What unit in an aircraft engine lubrication system is adjusted to maintain the desired system pressure?Oil pressure relief valve
Which of the following is a function of the fuel-oil heat exchanger on a turbojet engine?increases fuel temperature
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Section 7

Question Answer
What type of oil do most engine manufacturers recommend for new reciprocating engine break-in?Straight mineral oil
Cylinder walls are usually lubricated bysplashed or sprayed oil
What would be the probable result if the oil system pressure relief valve should stick in the open position on a turbine engine?Insufficient lubrication
If all other requirements can be met, what type of oil should be used to achieve theoretically perfect engine lubrication?The thinnest oil that will stay in place and maintain a reasonable film strength
In a reciprocating engine oil system, the temperature bulb senses oil temperatureat a point after the oil has passed through the oil cooler
The oil used in reciprocating engines has a relatively high viscosity due tolarge clearances and high operating temperatures
As an aid to cold-weather starting, the oil dilution system thins the oil withgasoline
What type of oil do most engine manufacturers recommend after new reciprocating engine break-in?Ashless-dispersant oil
Low oil pressure can be detrimental to the internal engine components. However, high oil pressureshould be limited to the engine manufacturer's recommendations
What is the source of most of the heat that is absorbed by the lubricating oil in a reciprocating engine?Pistons and cylinder walls
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Section 8

Question Answer
What is the primary purpose of the oil-to-fuel heat exchanger?cool the oil
Which of the following lubrication system components is never located between the pressure pump and the engine pressure system?Fuel line for oil dilution system
What is the purpose of the check valve generally used in a dry sump lubrication system?To prevent the oil from the supply tank from seeping into the crankcase during inoperative periods
After making a welded repair to a pressurized-type turbine engine oil tank, the tank should be pressure checked tonot less than 5 PSI plus the maximum operating pressure of the tank
The purpose of a relief valve installed in the tank venting system of a turbine engine oil tank is toprevent oil pump cavitation by maintaining a constant pressure on the oil pump inlet
The valve assemblies of opposed reciprocating engines are lubricated by means of apressure system
Manufacturers normally require turbine engine oil servicing within a short time after engine shutdown primarily toprevent overservicing
Lube system last chance filters in turbine engines are usually cleanedduring overhaul
According to Federal Aviation Regulations, oil tank fillers on turbine engines must be marked with the wordoil
An oil separator is generally associated with which of the following?Engine-driven vacuum pump
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Section 9

Question Answer
The oil dampened main bearing utilized in some turbine engines is used toprovide an oil film between the outer race and the bearing housing in order to reduce vibration tendencies in the rotor system, and to allow for slight misalignment
(1) Wet sump oil systems are most commonly used in gas turbine engines.(2) In most turbine engine oil tanks, a slight pressurization of the tank is desired to ensure a positive flow of oil.only No. 2 is true
In a jet engine which uses a fuel-oil heat exchanger, the oil temperature is controlled by a thermostatic valve that regulates the flow ofoil through the heat exchanger
How are the piston pins of most aircraft engines lubricated?By oil which is sprayed or thrown by the master or connecting rods
Possible failure related ferrous-metal particles in turbine engine oil cause an (electrical) indicating-type magnetic chip detector to indicate their presence bybridging the gap between the detector center (positive) electrode and the ground electrode
Specific gravity is a comparison of the weight of a substance to the weight of an equal volume ofdistilled water at a specific temperature
The purpose of a dwell chamber in a turbine engine oil tank is to provideseparation of entrained air from scavenged oil
An engine lubrication system pressure relief valve is usually located between thepump and the internal oil system
Why is expansion space required in an engine oil supply tank?For oil enlargment and collection of foam
The purpose of directing bleed air to the outer turbine case on some engines is toprovide optimum turbine blade tip clearance by controlling thermal expansion
The basic oil pressure relief valve setting for a newly overhauled engine is madein the overhual shop
A turbine engine dry sump lubrication system of the self-contained, high-pressure designconsists of pressure, breather, and Scavenge subsystems
What is the primary purpose of changing aircraft engine lubricating oils at predetermined periods?The oil become contaminated with moisture, acids, and finely divided suspended solid particles
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