Lubrication Systems

Question 1

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?

Answer 1

The oil pressure will be lower than normal.

Question 2

(1) Gas turbine and reciprocating engine oils can be mixed or used interchangeably.

(2) Most gas turbine engine oils are synthetic.

Answer 2

Only 2 is true.

Question 3

An oil separator is generally associated with which of the following?

Answer 3

Engine-driven vacuum pump.

Question 4

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’s what?

Answer 4

viscosity.

Question 5

Upon what quality or characteristic of a lubricating oil is its viscosity index based?

Answer 5

its rate of change in viscosity with temperature change.

Question 6

Lubricating oils with high viscosity index ratings are oils…

Answer 6

in which the viscosity does not vary much with temperature change.

Question 7

Compared to reciprocating engine oils, the types of oils used in turbine engines…

Answer 7

have less tendency to produce lacquer or coke.

Question 8

The oil used in reciprocating engines has a relatively high viscosity due to what?

Answer 8

large clearances and high operating temperatures.

Question 9

If all other requirements can be met, what type of oil should be used to achieve theoretically perfect engine lubrication?

Answer 9

The thinnest oil that will stay in place and maintain a reasonable film strength.

Question 10

Which of these characteristics is desirable in turbine engine oil?

Answer 10

High flash point.

Question 11

The viscosity of a liquid is a measure of its what?

Answer 11

resistance to flow.

Question 12

What type of oil system is usually found on turbine engines?

Answer 12

Dry sump, pressure, and spray.

Question 13

Which of the following helps determine the proper grade of oil to use in a particular engine?

Answer 13

Operating speeds of bearings.

Question 14

Specific gravity is a comparison of the weight of a substance to the weight of an equal volume of what?

Answer 14

distilled water at a specific temperature.

Question 15

Which of the following has the greatest effect on the viscosity of lubricating oil?

Answer 15

Temperature.

Question 16

What advantage do mineral base lubricants have over vegetable oil base lubricants when used in aircraft engines?

Answer 16

Chemical stability.

Question 17

The recommended aircraft engine lubricants are what?

Answer 17

mineral or synthetic base.

Question 18

High tooth pressures and high rubbing velocities, such as occur with spur-type gears, require the use of what?

Answer 18

An EP lubricant.

Question 19

Manufacturers normally require turbine engine oil servicing within a short time after engine shutdown primarily to what?

Answer 19

prevent overservicing.

Question 20

What type of oil do most engine manufacturers recommend for new reciprocating engine break-in?

Answer 20

Straight mineral oil.

Question 21

What type of oil do most engine manufacturers recommend after new reciprocating engine break-in?

Answer 21

Ashless dispersant oil.

Question 22

The type of oil pump most commonly used on turbine engines are classified as…

Answer 22

positive displacement.

Question 23

As a general rule, the mixture setting on a reciprocating engine operating at or near takeoff power that provides the best cooling is what?

Answer 23

FULL RICH

Question 24

The engine oil temperature regulator is usually located between which of the following on a dry sump reciprocating engine?

Answer 24

The scavenger pump outlet and the oil storage tank.

Question 25

What will happen to the return oil if the oil line between the scavenger pump and the oil cooler separates?

Answer 25

The return oil will be pumped overboard.

Question 26

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 is what?

Answer 26

lower than the pressure pump capabilities.

Question 27

(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.

Answer 27

Both 1 and 2 are true.

Question 28

In a reciprocating engine oil system, the temperature bulb senses oil temperature...

Answer 28

at a point after the oil has passed through the oil cooler.

Question 29

The oil dampened main bearing utilized in some turbine engines is used to what?

Answer 29

provide 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.

Question 30

What is the purpose of the last-chance oil filters?

Answer 30

to filter the oil immediately before it enters the main bearings.

Question 31

In a jet engine which uses a fuel/oil heat exchanger, the oil temperature is controlled by a thermostatic valve that regulates the flow of what?

Answer 31

oil through the heat exchanger.

Question 32

What prevents pressure within the lubricating oil tank from rising above or falling below ambient pressure (reciprocating engine)?

Answer 32

Oil tank vent.

Question 33

In an axial-flow turbine engine, compressor bleed air is sometimes used to aid in cooling the what?

Answer 33

turbine, vanes, blades, and bearings.

Question 34

Oil picks up the most heat from which of the following turbine engine components?

Answer 34

Turbine bearing.

Question 35

Which of the following is a function of the fuel/oil heat exchanger on a turbojet engine?

Answer 35

Increases fuel temperature.

Question 36

According to the Federal Aviation Regulations, oil tank fillers on turbine engines must be marked with the word...

Answer 36

"oil"

Question 37

Oil tank fillers on reciprocating engines are marked with the word...

Answer 37

"oil," in accordance with 14 CFR Part 25

Question 38

After making a welded repair to a pressurized type turbine engine oil tank, the tank should be pressure checked to what?

Answer 38

not less than 5 psi plus the maximum operating pressure of the tank.

Question 39

Why are fixed orifice nozzles used in the lubrication system of gas turbine engines?

Answer 39

To provide a relatively constant oil flow to the main bearings at all engine speeds.

Question 40

Possible failure related ferrous-metal particles in turbine engine oil cause an (electrical) indicating-type magnetic chip detector to indicate their presence by what?

Answer 40

bridging the gap between the detector center (positive) electrode and the ground electrode.

Question 41

What would be the probable result if the oil system pressure relief valve should stick in the open position on a turbine engine?

Answer 41

Insufficient lubrication.

Question 42

What is the primary purpose of the fuel/oil heat exchanger?

Answer 42

Cool the oil.

Question 43

What unit in an aircraft engine lubrication system is adjusted to maintain the desired system pressure?

Answer 43

Oil pressure relief valve.

Question 44

Low oil pressure can be detrimental to the internal engine components. However, high oil pressure...

Answer 44

should be limited to the engine manufacturer's recommendations.

Question 45

What is the primary purpose of the oil breather pressurization system that is used on turbine engines?

Answer 45

Provides a proper oil spray pattern from the main bearing oil jets.

Question 46

The purpose of directing bleed air to the outer turbine case on some engines is to what?

Answer 46

provide optimum turbine blade tip clearance by controlling thermal expansion.

Question 47

Some larger reciprocating engines use a compensating oil pressure relief valve to what?

Answer 47

provide a high engine oil pressure when the oil is cold and automatically lower the oil pressure when the oil warms up.

Question 48

In order to relieve excessive pump pressure in an engine's internal oil system, most engines are equipped with a what?

Answer 48

relief valve.

Question 49

What is the source of most of the heat that is absorbed by the lubricating oil in a reciprocating engine?

Answer 49

Pistons and cylinder walls.

Question 50

How are the teeth of the gears in the accessory section of an engine normally lubricated?

Answer 50

By splashed or sprayed oil.

Question 51

What is the purpose of the check valve generally used in a dry sump lubrication system?

Answer 51

To prevent the oil from the supply tank from seeping into the crankcase during inoperative periods.

Question 52

Which of the following factors has the least effect on the oil consumption of a specific engine?

Answer 52

Mechanical efficiency.

Question 53

How is the oil collected by the piston oil ring returned to the crankcase?

Answer 53

Through holes drilled in the piston oil ring groove.

Question 54

Which of the following lubrication system components is never located between the pressure pump and the engine pressure system?

Answer 54

Fuel line for oil dilution system.

Question 55

As an aid to cold-weather starting, the oil dilution system thins the oil with what?

Answer 55

gasoline.

Question 56

The basic oil pressure relief valve setting for a newly overhauled engine is made...

Answer 56

in the overhaul shop.

Question 57

Where is the oil temperature bulb located on a dry sump reciprocating engine?

Answer 57

Oil inlet line.

Question 58

Cylinder walls are usually lubricated by what?

Answer 58

splashed or sprayed oil.

Question 59

If an oil filter element becomes completely clogged, the what?

Answer 59

bypass valve will open, and the oil pump will supply unfiltered oil.

Question 60

Oil accumulation in the cylinders of an inverted inline engine and in the lower cylinders of a radial engine is normally reduced or prevented by what?

Answer 60

extended cylinder skirts.

Question 61

What is the primary purpose of changing aircraft engine lubricating oils at predetermined periods?

Answer 61

The oil becomes contaminated with moisture, acids, and finely divided suspended solid particles.

Question 62

What determines the minimum particle size which will be excluded or filtered by CUNO (staked disc, edge filtration) filter?

Answer 62

The spacer thickness.

Question 63

What is the primary purpose of the hopper located in the oil supply tank of some dry sump engine installations?

Answer 63

To reduce the time required to warm the oil to operating temperatures.

Question 64

The purpose of the flow control valve in a reciprocating engine oil system is to what?

Answer 64

direct oil through or around the oil cooler.

Question 65

Where are sludge chambers, when used in aircraft engine lubrication systems, usually located?

Answer 65

In the crankshaft throws.

Question 66

Why is an aircraft reciprocating engine oil tank on a dry sump lubrication system equipped with a vent line?

Answer 66

To prevent pressure buildup in the oil tank.

Question 67

Excessive oil is prevented from accumulating on the cylinder walls of a reciprocating engine by...

Answer 67

oil control rings on the pistons.

Question 68

(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.

Answer 68

Only 2 is true.

Question 69

The pumping capacity of the scavenger pump in a dry sump aircraft engine's lubrication system...

Answer 69

is greater than the capacity of the oil supply pump.

Question 70

In which of the following situations will the oil cooler automatic bypass valve be open the greatest amount?

Answer 70

Engine oil below normal operating temperature.

Question 71

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 output...

Answer 71

remains relatively constant (at a given RPM) with less oil being returned to the pump inlet by the relief valve.

Question 72

The valve assemblies of opposed reciprocating engines are lubricated by means of a what?

Answer 72

pressure system.

Question 73

What will result if an oil filter becomes completely blocked?

Answer 73

Oil will flow at the normal rate through the system.

Question 74

A turbine engine dry sump lubrication system of the self-contained, high-pressure design...

Answer 74

consists of pressure, breather, and scavenge subsystems.

Question 75

Lube system last-chance filters in turbine engines are usually cleaned...

Answer 75

during overhaul.

Question 76

How are the piston pins of most aircraft engines lubricated?

Answer 76

By oil which is sprayed or thrown by the master or connecting rods.

Question 77

The vent line connecting the oil supply tank and the engine in some dry sump engine installation permits what?

Answer 77

the oil tank to be vented through the normal engine vent.

Question 78

An engine lubrication system pressure relief valve is usually located between the what?

Answer 78

pump and the internal oil system.

Question 79

Where is the oil of a dry sump reciprocating engine exposed to the temperature control valve sensing unit?

Answer 79

Oil cooler inlet.

Question 80

Under which of the following conditions is the oil cooler flow control valve open on a reciprocating engine?

Answer 80

When the temperature of the oil returning from the engine is too low.

Question 81

The purpose of a relief valve installed in the tank venting system of a turbine engine oil tank is to what?

Answer 81

prevent oil pump cavitation by maintaining a constant pressure on the oil pump inlet.

Question 82

In a reciprocating engine, oil is directed from the pressure relief valve to the inlet side of the what?

Answer 82

pressure pump.

Question 83

If the oil in the oil cooler core and annular jacket becomes congealed, what unit prevents damage to the cooler?

Answer 83

Surge protection valve.

Question 84

The primary source of oil contamination in a normally operating reciprocating engine is what?

Answer 84

combustion deposits due to combustion chamber blow-by and oil migration on the cylinder walls.

Question 85

A drop in oil pressure may be caused by what?

Answer 85

foreign material under the relief valve.

Question 86

The main oil filters strain the oil at which point in the system?

Answer 86

Just as it leaves the pressure pump.

Question 87

Which of the following prevents oil from entering the main accessory case when the engine is not running?

Answer 87

Check valve.

Question 88

An oil tank having a capacity of 5 gallon must have an expansion space of what?

Answer 88

2 quarts.

Question 89

As a general rule, a small amount of small fuzzy particles or gray metallic paste on a turbine engine magnetic chip detector...

Answer 89

is considered to be the result of normal wear.

Question 90

Why is expansion space required in an engine oil supply tank?

Answer 90

For oil enlargement and collection of foam.

Question 91

The purpose of a dwell chamber in a turbine engine oil tank is to provide what?

Answer 91

separation of entrained air from scavenged oil.

Question 92

Which of the following bearing types must be continuously lubricated by pressure oil?

Answer 92

Plain.