Lubrication Systems

Question 1

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?

a. the oil pressure will be higher than normal
b. the oil temperature and oil pressure will be higher than normal
c. the oil pressure will be lower than normal

Answer 1

c.

Question 2

2. (1) Gas turbine and reciprocating engine oils can be mixed or used interchangeably.
   (2) Most gas turbine engine oils are synthetic.
   Regarding the above statements,

a. only No. 2 is true
b. both No. 1 and No. 2 are true
c. neither No. 1 nor No. 2 is true

Answer 2

a.

Question 3

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

a. engine-driven oil pressure pump
b. engine-driven vacuum pump
c. cuno oil filter

Answer 3

b.

Question 4

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

a. flash point
b. specific gravity
c. viscosity

Answer 4

c.

Question 5

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

a. its resistance to flow at a standard temperature as compared to high grade paraffin-base oil at the same temperature
b. its rate of change in viscosity with temperature change
c. its rate of flow through an orifice at a standard temperature

Answer 5

b.

Question 6

6. Lubricating oils with high viscosity index ratings are oils

a. in which the viscosity does not vary much with temperature change
b. in which the viscosity varies considerably with temperature change
c. which have high SAE numbers

Answer 6

a.

Question 7

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

a. are required to carry and disperse a higher level of combustion by-products
b. may permit a somewhat higher level of carbon formation in the engine
c. have less tendency to produce lacquer or coke

Answer 7

c.

Question 8

8. The oil used in reciprocating engines has a relatively high viscosity due to

a. the reduced ability of thin oils to maintain adequate film strength at altitude (reduced atmospheric pressure)
b. relatively high rotational speeds
c. large clearances and high operating temperatures

Answer 8

c.

Question 9

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

a. the thinnest oil that will stay in one place and maintain a reasonable film strength
b. an oil that combines high viscosity and low demulsibility
c. an oil that combines a low viscosity index and a high neutralization number

Answer 9

a.

Question 10

10. In addition to lubricating (reducing friction between moving parts), engine oil performs what functions?
11. Cools.
12. Seals.
13. Cleans.
14. Prevents corrosion.
15. Cushions impact (shock) loads.

a. 1, 2, 3, 4
b. 1, 2, 3, 4, 5
c. 1, 3, 4

Answer 10

b.

Question 11

11. Which of these characteristics is desirable in turbine engine oil?

a. low flash point
b. high flash point
c. high volatility

Answer 11

b.

Question 12

12. The viscosity of a liquid is a measure of its

a. resistance to flow
b. rate of change of internal friction with change in temperature
c. weight, or density

Answer 12

a.

Question 13

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

a. dry sump, pressure, and spray
b. dry sump, dip, and splash
c. wet sump, spray, and splash

Answer 13

a.

Question 14

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

a. adequate lubrication in various attitudes of flight
b. positive introduction of oil to the bearings
c. operating speeds of bearings

Answer 14

c.

Question 15

15. Specific gravity is a comparison of the weight of a substance to the weight of an equal volume of

a. oil at a specific temperature
b. distilled water at a specific temperature
c. mercury at a specific temperature

Answer 15

b.

Question 16

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

a. temperature
b. pressure
c. volatility

Answer 16

a.

Question 17

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

a. cooling ability
b. chemical stability
c. friction resistance

Answer 17

b.

Question 18

18. The recommended aircraft engine lubricants are

a. animal, mineral, or synthetic based
b. mineral or synthetic based
c. vegetable, mineral, or synthetic based

Answer 18

b.

Question 19

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

a. an EP lubricant
b. straight mineral oil
c. metallic ash detergent oil

Answer 19

a.

Question 20

20. Manufacturers normally require turbine engine oil servicing within a short time after engine shutdown primarily to

a. prevent overservicing
b. help dilute and neutralize any contaminants that may already be present in the engine’s oil system
c. provide a better indication of any oil leaks in the system

Answer 20

a.

Question 21

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

a. ashless-dispersant oil
b. straight mineral oil
c. semi-synthetic oil

Answer 21

b.

Question 22

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

a. metallic-ash detergent oil
b. ashless-dispersant oil
c. straight mineral oil

Answer 22

b.

Question 23

23. The type of oil pumps most commonly used on turbine engines are classified as

a. positive displacement
b. variable displacement
c. constant speed

Answer 23

a.

Question 24

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

a. FULL RICH
b. LEAN
c. FULL LEAN

Answer 24

a.

Question 25

25. The engine oil temperature regulator is usually located between which of the following on a dry sump reciprocating engine? a. the engine oil supply pump and the internal lubrication system b. the scavenger pump outlet and the oil storage tank c. the oil storage tank and the engine oil supply pump

Answer 25

b.

Question 26

26. What will happen to the return oil if the oil line between the scavenger pump and the oil cooler separates? a. oil will accumulate in the engine b. the return oil will be pumped overboard c. the scavenger return line check valve will close and force the oil to bypass directly to the intake side of the pressure pump

Answer 26

b.

Question 27

27. 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 a. lower than the pump inlet pressure b. lower than the pressure pump capabilities c. higher than the pressure pump capabilities

Answer 27

b.

Question 28

28. (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. Regarding the above statements, a. only No.1 is true b. only No. 2 is true c. both No. 1 and No. 2 are true

Answer 28

c.

Question 29

29. In a reciprocating engine oil system, the temperature bulb senses oil temperature a. at a point after the oil has passed through the oil cooler b. while the oil is in the hottest area of the engine c. immediately before the oil enters the oil cooler

Answer 29

a.

Question 30

30. The oil dampened main bearing utilized in some turbine engines is used to a. provide lubrication of bearings from the beginning of starting rotation until normal oil pressure is established b. 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 c. dampen surges in oil pressure to the bearings

Answer 30

b.

Question 31

31. What is the purpose of the last chance oil filters? a. to prevent damage to the oil spray nozzle b. to filter the oil immediately before it enters the main bearings c. to assure a clean supply of oil to the lubrication system

Answer 31

b.

Question 32

32. 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 a. fuel through the heat exchanger b. both fuel and oil through the heat exchanger c. oil through the heat exchanger

Answer 32

c.

Question 33

33. What prevents pressure within the lubricating oil tank from rising above or falling below ambient pressure (reciprocating engine)? a. oil tank check valve b. oil pressure relief valve c. oil tank vent

Answer 33

c.

Question 34

34. In an axial-flow turbine engine, compressor bleed air is sometimes used to aid in cooling the a. fuel b. inlet guide vanes c. turbine, vanes, blades, and bearings

Answer 34

c.

Question 35

35. Oil picks up the most heat from which of the following turbine engine components? a. rotor coupling b. compressor bearing c. turbine bearing

Answer 35

c.

Question 36

36. Which of the following is a function of the fuel-oil heat exchanger on a turbojet engine? a. aerates the fuel b. emulsifies the oil c. increases fuel temperature

Answer 36

c.

Question 37

37. According to Federal Aviation Regulations, oil tank fillers on turbine engines must be marked with the word a. 'oil' and the type and grade of oil specified by the manufacturer b. 'oil' and tank capacity c. 'oil'

Answer 37

c.

Question 38

38. Oil tank fillers on reciprocating engines are marked with the word a. "oil" and tank capacity, in accordance with 14 CFR Part 45 b. "oil", type, and grade, in accordance with 14 CFR Part 33 c. "oil" in accordance with 14 CFR Part 23

Answer 38

c.

Question 39

39. After making a welded repair to a pressurized-type turbine engine oil tank, the tank should be pressure checked to a. not less than 5 PSI plus the maximum operating pressure of the tank b. not less than 5 PSI plus the average operating pressure of the tank c. 5 PSI

Answer 39

a.

Question 40

40. Why are fixed orifice nozzles used in the lubrication system of gas turbine engines? a. to provide a relatively constant oil flow to the main bearings at all engine speeds b. to keep back pressure on the oil pump, thus preventing an air lock c. to protect the oil seals by preventing excessive pressure from entering the bearing cavities

Answer 40

a.

Question 41

41. Possible failure related ferrous-metal particles in turbine engine oil cause an (electrical) indicating-type magnetic chip detector to indicate their presence by a. disturbing the magnetic lines of flux around the detector tip b. bridging the gap between the detector center (positive) electrode and the ground electrode c. generating a small electric current that is caused by the particles being in contact with the dissimilar metal of the detector tip

Answer 41

b.

Question 42

42. What would be the probable result if the oil system pressure relief valve should stick in the open position on a turbine engine? a. increased oil pressure b. decreased oil pressure c. insufficient lubrication

Answer 42

c.

Question 43

43. What is the primary purpose of the oil-to-fuel heat exchanger? a. cool the fuel b. cool the oil c. de-aerate the oil

Answer 43

b.

Question 44

44. What unit in an aircraft engine lubrication system is adjusted to maintain the desired system pressure? a. oil pressure relief valve b. oil viscosity valve c. oil pump

Answer 44

a.

Question 45

45. Low oil pressure can be detrimental to the internal engine components. However, high oil pressure a. should be limited to the engine manufacturer's recommendations b. has a negligible effect c. will not occur because of pressure losses around the bearings

Answer 45

a.

Question 46

46. What is the primary purpose of the oil breather pressurization system that is used on turbine engines? a. prevents foaming of the oil b. allows aeration of the oil for better lubrication because of the air/oil mist c. provides a proper oil spray pattern from the main bearing oil jets

Answer 46

c.

Question 47

47. The purpose of directing bleed air to the outer turbine case on some engines is to a. provide optimum turbine blade tip clearance by controlling thermal expansion b. provide up to 100 percent kinetic energy extraction from the flowing gases c. allow operation in a thermal environment 600 to 800 degrees F above the temperature limits of turbine blade and vane alloys

Answer 47

a.

Question 48

48. Some larger reciprocating engines use a compensating oil pressure relief valve to a. provide a high engine oil pressure when the oil is cold and automatically lower the oil pressure when the oil warms up b. compensate for changes in atmospheric pressure that accompany altitude changes c. automatically keep oil pressure nearly the same whether the oil is warm or cold

Answer 48

a.

Question 49

49. In order to relieve excessive pump pressure in an engine's internal oil system, most engines are equipped with a a. vent b. bypass valve c. relief valve

Answer 49

c.

Question 50

50. What is the source of most of the heat that is absorbed by the lubricating oil in a reciprocating engine? a. crankshaft main bearings b. exhaust valves c. pistons and cylinder walls

Answer 50

c.

Question 51

51. How are the teeth of the gears in the accessory section of an engine normally lubricated? a. by splashed or sprayed oil b. by submerging the load-bearing portions in oil c. by surrounding the load-bearing portions with baffles or housings within which oil pressure can be maintained

Answer 51

a.

Question 52

52. What is the purpose of the check valve generally used in a dry sump lubrication system? a. to prevent the scavenger pump from losing its prime b. to prevent the oil from the supply tank from seeping into the crankcase during inoperative periods c. to prevent the oil from the pressure pump from entering the scavenger system

Answer 52

b.

Question 53

53. From the following, identify the factor that has the least effect on the oil consumption of a specific engine. a. mechanical efficiency b. engine RPM c. lubricant characteristics

Answer 53

a.

Question 54

54. How is the oil collected by the piston oil ring returned to the crankcase? a. down vertical slots cut in the piston wall between the piston oil ring groove and the piston skirt b. through the holes drilled in the piston oil ring groove c. through holes drilled in the piston pin recess

Answer 54

b.

Question 55

55. Which of the following lubrication system components is never located between the pressure pump and the engine pressure system? a. oil temperature bulb b. fuel line for oil dilution system c. check valve

Answer 55

b.

Question 56

56. As an aid to cold-weather starting, the oil dilution system thins the oil with a. kerosene b. alcohol c. gasoline

Answer 56

c.

Question 57

57. The basic oil pressure relief valve setting for a newly overhauled engine is made a. within the first 30 seconds of engine operation b. when the oil is at a higher than normal temperature to assure high oil pressure at normal oil temperature c. in the overhaul shop

Answer 57

c.

Question 58

58. Where is the oil temperature bulb located on a dry sump reciprocating engine? a. oil inlet line b. oil cooler c. oil outlet line

Answer 58

a.

Question 59

59. Cylinder walls are usually lubricated by a. splashed or sprayed oil b. a direct pressure system fed through the crankshaft, connecting rods, and the piston pins to the oil control ring groove in the piston c. oil that is picked up by the oil control ring when the piston is at bottom center

Answer 59

a.

Question 60

60. If a full-flow oil filter is used on an aircraft engine, and the filter becomes completely clogged, the a. oil supply to the engine will be blocked b. oil will be bypassed back to the oil tank hopper where larger sediments and foreign matter will settle out prior to passage through the engine c. bypass valve will open and the oil pump will supply unfiltered oil to the enginee

Answer 60

c.

Question 61

61. 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 by a. reversed oil control rings b. routing the valve-operating mechanism lubricating oil to a separate scavenger pump c. extended cylinder skirts

Answer 61

c.

Question 62

62. What is the primary purpose of changing aircraft engine lubricating oils at predetermined periods? a. the oil becomes diluted with gasoline washing past the pistons into the crankcase b. the oil becomes contaminated with moisture, acids, and finely divided suspended solid particles c. exposure to heat and oxygen causes a decreased ability to maintain a film under load

Answer 62

b.

Question 63

63. What determines the minimum particle size which will be excluded or filtered by a cuno-type (stacked disc, edge filtration) filter? a. the disc thickness b. the spacer thickness c. both the number and thickness of the discs in the assembly

Answer 63

b.

Question 64

64. What is the primary purpose of the hopper located in the oil supply tank of some dry sump engine installations? a. to reduce the time required to warm the oil to operating temperatures b. to reduce surface aeration of the hot oil and thus reduce oxidation and the formation of sludge and varnish c. to impart a centrifugal motion to the oil entering the tank so that the foreign particles in the oil will separate more readily

Answer 64

a.

Question 65

65. The purpose of the flow control valve in a reciprocating engine oil system is to a. direct oil through or around the oil cooler b. deliver cold oil to the hopper tank c. compensate for volumetric increases due to foaming of the oil

Answer 65

a.

Question 66

66. Where are sludge chambers, when used in aircraft engine lubrication systems, usually located? a. in the crankshaft throws b. adjacent to the scavenger pumps c. in the oil storage tank

Answer 66

a.

Question 67

67. Why is an aircraft reciprocating engine oil tank on a dry sump lubrication system equipped with a vent line? a. to prevent pressure buildup in the reciprocating engine crankcase b. to eliminate foaming in the oil tank c. to prevent pressure buildup in the oil tank

Answer 67

c.

Question 68

68. Excessive oil is prevented from accumulating on the cylinder walls of a reciprocating engine by a. the design shape of the piston skirt b. internal engine pressure bleeding past the ring grooves c. oil control rings on the pistons

Answer 68

c.

Question 69

69. (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. Regarding the above statements, a. both No. 1 and No. 2 are true b. only No. 2 is true c. neither No. 1 nor No. 2 is true

Answer 69

b.

Question 70

70. The pumping capacity of the scavenger pump in a dry sump aircraft engine's lubrication system a. is greater than the capacity of the oil supply pump b. is less than the capacity of the oil supply pump c. is usually equal to the capacity of the oil supply pump in order to maintain constant oiling conditions

Answer 70

a.

Question 71

71. In which of the following situations will the oil cooler automatic bypass valve be open the greatest amount? a. engine oil above normal operating temperature b. engine oil below normal operating temperature c. engine stopped with no oil flowing after runup

Answer 71

b.

Question 72

72. 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 a. increases as the resistance offered to the flow of oil increases b. remains relatively constant (at a given RPM) with less oil being returned to the pump inlet by the relief valve c. remains relatively constant (at a given RPM) with more oil being returned to the pump inlet by the relief valve

Answer 72

b.

Question 73

73. The valve assemblies of opposed reciprocating engines are lubricated by means of a a. gravity feed system b. splash and spray system c. pressure system

Answer 73

c.

Question 74

74. What will result if an oil filter becomes completely blocked? a. oil will flow at a reduced rate through the system b. oil flow to the engine will stop c. oil will flow at the normal rate through the system

Answer 74

c.

Question 75

75. A turbine engine dry sump lubrication system of the self-contained, high-pressure design a. has no heat exchanger b. consists of pressure, breather, and scavenge subsystems c. stores oil in the engine crankcase

Answer 75

b.

Question 76

76. Lube system last chance filters in turbine engines are usually cleaned a. during annual inspection b. during 100-hour inspection c. during overhaul

Answer 76

c.

Question 77

77. How are the piston pins of most aircraft engines lubricated? a. by pressuring oil through a drilled passageway in the heavy web portion of the connecting rod b. by oil which is sprayed or thrown by the master or connecting rods c. by the action of the oil control ring and the series of holes drilled in the ring groove directing oil to the pin and piston pin boss

Answer 77

b.

Question 78

78. The vent line connecting the oil supply tank and the engine in some dry sump engine installations permits a. pressurization of the oil supply to prevent cavitation of the oil supply pump b. oil vapors from the engine to be condensed and drained into the oil supply tank c. the oil tank to be vented through the normal engine vent

Answer 78

c.

Question 79

79. An engine lubrication system pressure relief valve is usually located between the a. oil cooler and the scavenger pump b. scavenger pump and the external oil system c. pump and the internal oil system

Answer 79

c.

Question 80

80. Where is the oil of a dry sump reciprocating engine exposed to the temperature control valve sensing unit? a. oil cooler inlet b. engine outlet c. engine inlet

Answer 80

a.

Question 81

81. Under which of the following conditions is the oil cooler flow control valve open on a reciprocating engine? a. when the temperature of the oil returning from the engine is too high b. when the temperature of the oil returning from the engine is too low c. when the scavenger pump output volume exceeds the engine pump input volume

Answer 81

b.

Question 82

82. The purpose of a relief valve installed in the tank venting system of a turbine engine oil tank is to a. prevent oil pump cavitation by maintaining a constant pressure on the oil pump inlet b. maintain internal tank air pressure at the ambient atmospheric level regardless of altitude or rate of change in altitude c. maintain a positive internal pressure in the oil tank after shutdown to prevent oil pump cavitation on engine start

Answer 82

a.

Question 83

83. In a reciprocating engine, oil is directed from the pressure relief valve to the inlet side of the a. scavenger pump b. oil temperature regulator c. pressure pump

Answer 83

c.

Question 84

84. If the oil in the oil cooler core and annular jacket becomes congealed, what unit prevents damage to the cooler? a. oil pressure relief valve b. airflow control valve c. surge protection valve

Answer 84

c.

Question 85

85. The primary source of oil contamination in a normally operating reciprocating engine is a. metallic deposits as a result of engine wear b. atmospheric dust and pollution c. combustion deposits due to combustion chamber blow-by and oil migration on the cylinder walls

Answer 85

c.

Question 86

86. A drop in oil pressure may be caused by a. the temperature regulator sticking open b. the bypass valve sticking open c. foreign material under the relief valve

Answer 86

c.

Question 87

87. The main oil filters strain the oil at which point in the system? a. immediately after it leaves the scavenger pump b. immediately before it enters the pressure pump c. just as it leaves the pressure pump

Answer 87

c.

Question 88

88. Which type valve prevents oil from entering the main accessory case when the engine is not running? a. bypass b. relief c. check

Answer 88

c.

Question 89

89. An oil tank having a capacity of 5 gallons must have an expansion space of a. 2 quarts b. 4 quarts c. 5 quarts

Answer 89

a.

Question 90

90. As a general rule, a small amount of small fuzzy particles or gray metallic paste on a turbine engine magnetic chip detector a. is considered to be the result of normal wear b. indicates an imminent component failure c. indicates accelerated generalized wear

Answer 90

a.

Question 91

91. Why is expansion space required in an engine oil supply tank? a. to eliminate oil foaming b. for oil enlargement and collection of foam c. for proper oil tank ventilation

Answer 91

b.

Question 92

92. The purpose of a dwell chamber in a turbine engine oil tank is to provide a. a collection point for sediments b. for a pressurized oil supply to the oil pump inlet c. separation of entrained air from scavenged oil

Answer 92

c.

Question 93

93. Which of the following bearing types must be continuously lubricated by pressure oil? a. ball b. roller c. plain

Answer 93

c.