LUBRICANTS AND FUELS

Question 1

What are the 4 main tasks for engine oil?

Answer 1

• Lubricating
• Cooling
• Cleaning
• Corrosion protection

Question 2

What generally is lubrication needed for?

Answer 2

Reduce friction metered metal surfaces.

Question 3

How does the oil cool areas?

Answer 3

Heat is transferred to the oil when in contact with metal surfaces.

Question 4

How does oil clean?

Answer 4

Clean contaminants (abrasion from gears, bearings or FOD)

Carries particles until caught in oil filter.

Question 5

What can small contaminants in the oil indicate?

Answer 5

Internal wear.

Question 6

What engines are mineral oils only used on?

Answer 6

Piston type.

Question 7

What are the 3 types of synthetic oil?

Answer 7

Type 1- used on older aircraft

Type 2- used in modern gas turbine

Type 3- higher thermal stability and viscosity at high temps than type 2. Used on special aircraft

Question 8

What are advantages of synthetic oils?

Answer 8

Better viscosity, thermal stability and high pressure resistance.

Question 9

What is a disadvantage of synthetic oils?

Answer 9

• Higher price.
• Harmful to skin.
• Cannot be mixed with other synthetic oils from other manufacturers, even if same type.

Question 10

What is the viscosity index of engine oils?

Answer 10

The effect temperature has on the viscosity of oil.

Higher number- least change

Question 11

What is the viscosity of an oil?

Answer 11

Property of a fluid offering resistance to flow.

Question 12

What is the pour point of an oil?

Answer 12

Lowest temp that oil will visibly move in a 31.75mm test tube held horizontally for 5 seconds.

Question 13

What is a flash point of an oil?

Answer 13

Lowest temp oil will give off enough vapour to ‘flash’ when a flame is applied.

Question 14

What is the fire point of an oil?

Answer 14

Lowest temp oil will ignite and burn continuously for at least 5 seconds.

Question 15

What is the volatility of an oil?

Answer 15

Ease in which a liquid is converted into a vaporous state.

Question 16

What is the acidity of an oil?

Answer 16

Measure of corrosion tendencies of the oil.

Question 17

What is oil foaming?

Answer 17

Measure of resistance of oil to separate from entrapped air.

Question 18

What is the oxidation and thermal stability of an engine oil?

Answer 18

Ability of oil to resist formation of hard carbon and sludge at high temps.

Question 19

What is coking of an oil?

Answer 19

Amount of carbon residue remaining in the oil after being subjected to extreme heating.

Question 20

What can be mixed with oils to impart desirable characteristics?

Answer 20

Chemical additives.

Question 21

What will a typical fuel be composed of?

Answer 21

84% carbon, 16% hydrogen and small amount of impurities (sulphur, water, nitrogen)

Question 22

What is a high volatile fuel desirable for?

Answer 22

Engine starts in cold weather and in flight.

Question 23

What is the Califorc value for?

Answer 23

Measures combustion.

Question 24

If the ambient pressure decreases, what happens to the vaporising rate of the fuel?

Answer 24

Vaporises easier.

Question 25

What is the fuel density a ratio between?

Answer 25

Mass and volume.

Question 26

What do static dissapator additives do?

Answer 26

Reduce hazardous effect of static electricity.

Question 27

What do anti-oxidants do in fuels?

Answer 27

Prevent formation of gum deposits caused by oxidisation.

Question 28

What is the fire triangle?

Answer 28

Heat, oxygen, fuel

Question 29

How far must the refuelled truck be away from the aircraft?

Answer 29

7m

Question 30

Where would refuelling leaks usually occur?

Answer 30

Vent tank openings.

Question 31

Why must the fuel truck be connected to the aircraft by a ground lead?

Answer 31

Prevents sparks from static electricity.

Question 32

What is a category 4 tank?

Answer 32

Only be entered via internal openings.