Subject K - Lubrication Systems

Question 1

What is straight mineral oil?

Answer 1

It is a type of natural lubricating oil that has no additives for foaming, cleaning, or viscosity.

Question 2

What is ashless dispersant oil?

Answer 2

It is a type of oil with additives that evenly spread contaminates throughout the oil. The additives that are used do not form ashes.

Question 3

What is synthetic oil?

Answer 3

Synthetic oil is an oil that is man-made through the process of chemically altering the molecular structure of petroleum oil in order to achieve the desired characteristics.

Question 4

What is meant by multi viscosity oil?

Answer 4

It is a type of oil that has varying viscosity according to the temperature.

Question 5

What are the purposes of reciprocating engine oil?

Answer 5

it cleans, cools, cushions, seals, and lubricates parts.

Question 6

What is the most important property that aircraft reciprocating engine oil must possess?

Answer 6

Viscosity

Question 7

What factors must be considered in determining the proper grade oil to use in a specific engine?

Answer 7

The operating load, rotational speeds, and operating temperatures are the most important factors to be considered.

Question 8

What is the purpose of the oil flow control valve “oil cooler bypass valve”?

Answer 8

When the oil is cool the valve will direct it around the oil cooler, and when the oil is hot the valve will direct it through the cooler.

Question 9

What are the main oil contaminants?

Answer 9

They are gasoline, moisture, acid, dirt, carbon, and metallic particles.

Question 10

From what location on a reciprocating engine is the oil temperature usually taken?

Answer 10

In either a wet sump or dry sump the bulb is located where it measures the oil temperature before it enters the hot section of the engine.
in dry sump, the oil temp bulb is located anywhere in the oil inlet line between the tank and the engine.
In wet sump the temp bulb is located where it senses the temp after the oil passes through the oil cooler.

Question 11

What do metallic particles on an oil screen indicate?

Answer 11

Metallic particles may be an indication of an internal failure of the engine.

Question 12

What could cause oil foaming?

Answer 12

Foaming can be caused by diluted oil, contaminated oil, or the oil level is too high.

Question 13

What would be an indication of blocked oil cooler passages?

Answer 13

High oil temperature

Question 14

What would be an indication of an inadequate oil supply?

Answer 14

Low oil pressure and high oil temperatures.

Question 15

What type of oil is used in turbine engine lubrication systems?

Answer 15

Specifically developed synthetic oils

Question 16

Where can you find the specified grade of oil for a particular aircraft?

Answer 16

Oil grade can be found in the Airplane Flight Manual(AFM) , or the pilot’s operating handbook (POH).

Question 17

What are two types of oil coolers used in turbine engine lubrication systems?

Answer 17

The air-cooled oil cooler and fuel-cooled oil are the two basic types in general use.

Question 18

What is the meaning of oil flash point? Fire point?

Answer 18

Oil flash point is the temperature at which the oil will begin to give off ignitable vapors.
The fire point is the temp at which there are sufficient vaports to support continuous flame.

Question 19

What is the weight of aircraft engine oil?

Answer 19

Approximately 7.5 pounds per U.S. gallon

Question 20

What is the purpose of the oil dilution system?

Answer 20

The oil dilution system thins the oil by introducing fuel into the lubrication system which makes cold weather starting easier.
Fuel is used because than it will evaporate out of the oil and leave through the crankcase breather.

Question 21

What is the primary purpose of engine oil lubricant?

Answer 21

To reduce friction

Question 22

What is S.O.A.P. (spectrometric oil analysis program) analysis?

Answer 22

S.O.A.P. is an oil analysis system that establishes a trend to measure engine health. One test does not do much unless something is very wrong.

Question 23

Where are carbon seals used in turbine engines?

Answer 23

Carbon seals are used in aircraft gearboxes, air-turbine motor starters, and main shaft seals.

Question 24

What is the key purpose of lubrication in a turbine engine?

Answer 24

For lubrication of the main shaft bearings.

Question 25

Where are engine oil filters located?

Answer 25

They are located between the oil pump output and the engine bearings.

Question 26

Why do reciprocating engines require oil with a high viscosity index?(small changes in viscosity over a wide temp range)

Answer 26

HIgher viscosity indexes allow for easier starting in cold temp and prevents the oil from becoming too thin at operating temp to protect bearings under operating loads.

Question 27

Why do reciprocating engines require high viscosity oil ?( oil flows slowly)

Answer 27

Higher viscosity oil performs better in reciprocating engines because they have large clearances, high operating temperatures and high bearing pressure.

Question 28

What two factors impact fluid viscosity?

Answer 28

Temperature and Pressure, although pressure has a very small effect of viscosity.