Engine Lubrication Systems

Question 1

Name one type of oil filter used on aircraft engines.

Answer 1

Canister

Question 2

What is straight mineral oil?

Answer 2

Natural lubricating oil that has no additives for foaming, cleaning, or viscosity

Question 3

What is ashless dispersant (AD) oil?

Answer 3

Mineral oil with additives that evenly spread contaminates throughout the oil

Question 4

What is synthetic oil?

Answer 4

Chemically altered petroleum oil manufactured to achieve the desired characteristics

Question 5

What is meant by multi-viscosity oil?

Answer 5

When the oil is cold it will have low viscosity but when it warms up the viscosity will increase for better lubrication

Question 6

What are the purposes of reciprocating engine oil?

Answer 6

It cleans, cools, cushions, seals, and lubricates parts

Question 7

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

Answer 7

Viscosity

Question 8

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

Answer 8

Operating load, rotational speeds, and operating temperatures

Question 9

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

Answer 9

When the oil is cool the valve will direct it around the oil cooler, when it warms it will direct it through the oil cooler

Question 10

What are some oil contaminants?

Answer 10

Carbon, Acid, Dirt, Moisture, Gasoline, Metallic particles

Question 11

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

Answer 11

Before it enters into the hot section

Question 12

What do metallic particles on an oil screen indicate?

Answer 12

Internal failure of the engine

Question 13

What could cause oil foaming?

Answer 13

Diluted Oil, Contaminated Oil, Oil level is too high

Question 14

What would be an indication of blocked oil cooler passages?

Answer 14

High oil temperature

Question 15

What would be an indication of an inadequate oil supply?

Answer 15

Low oil pressure and high oil temperature

Question 16

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

Answer 16

Specially developed synthetic oils

Question 17

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

Answer 17

In the Airplane Flight Manual (AFM) or the Pilot’s Operating Handbook (POH)

Question 18

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

Answer 18

Air and Fuel cooled

Question 19

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

Answer 19

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

Question 20

What is the weight of aircraft engine oil?

Answer 20

Approximately 7.5 pounds per US gallon

Question 21

What is the purpose of an oil dilution system?

Answer 21

Thins the oil by introducing fuel into the lubrication system which makes cold weather starting easier

Question 22

What is the primary purpose of engine oil lubricant?

Answer 22

Reduce friction

Question 23

What is the S.O.A.P. analysis?

Answer 23

Spectrometric Oil Analysis Program that establishes a trend to measure engine health

Question 24

Where are carbon seals used in a turbine engine?

Answer 24

Gearboxes, air-turbine motor starters, and main shaft seals

Question 25

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

Answer 25

Lubrication of the main shaft bearings

Question 26

Where are engine oil filters located?

Answer 26

Between the oil pump output and the engine bearings

Question 27

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

Answer 27

Allow for easier starting in cold temperatures and prevents the oil from becoming too thin at operating temperatures

Question 28

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

Answer 28

They have large clearances, high operating temperatures, and high bearing pressures

Question 29

What two factors impact fluid viscosity?

Answer 29

Temperature and pressure

Question 30

What is the purpose of ashless dispersant oil?

Answer 30

To prevent sludge build up and oil filters from clogging

Question 31

What is the most critical lubrication point in a gas turbine engine?

Answer 31

Turbine Bearing

Question 32

Why is an oil tank required to have expansion space?

Answer 32

Thermal expansion and air in the return oil

Question 33

Name some areas of a turbine engine oil system where oil screens/filters may be located.

Answer 33

Oil pressure system, Scavenge system, before the oil jets

Question 34

Why do dry sump reciprocating engines have a smaller sump?

Answer 34

To prevent a large accumulation of oil in the engine crankcase.