M15.9 Lubricants And Fuels

Question 1

Main tasks of engine oil?

Answer 1

Lubrication
Cooling
Cleaning
Corrosion protection

Question 2

Two types of engine oils?

Answer 2

Synthetic oils
Mineral oils

Question 3

Three types of synthetic oils?

Answer 3

Type 1- first generation synthetic oil- Old gas turbine engines
Type 2- used on modern gas turbine engines
Type 3- higher thermal stability and viscosity at high temp than type 2. Only used for special aircraft

Question 4

Advantages and disadvantages of synthetic oil?

Answer 4

Advantages are better viscosity, better thermal stability and high pressure resistance disadvantages are they have a high price, not mixable and cause skin irritation

Question 5

What is viscosity index?

Answer 5

The effect temperature has on viscosity of the oil
Higher number indicates least affected by a change in temp

Question 6

What is viscosity?

Answer 6

The internal resistance of a fluid against deformation

Question 7

Viscosity of oil depends on what?

Answer 7

Temperature
High viscosity at low temp
Low viscosity at high temp

Question 8

What is the pour point?

Answer 8

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

Question 9

Pour point of type two oil?

Answer 9

-57 degrees Celsius

Question 10

What is a flash point?

Answer 10

The lowest temperature that an oil will give off enough vapour to flash when a flame is applied. Should be as high as possible

Question 11

Type 2 oil flash point?

Answer 11

250 degrees Celsius

Question 12

What happens to oil when it reacts with oxygen?

Answer 12

Gets thicker and increase’s viscosity

Question 13

What types of resistance does oil need?

Answer 13

Pressure resistance
Oxidation resistance

Question 14

What is thermal stability?

Answer 14

Describes oil resistance to the decomposition of the oil at high temps.

Question 15

What is volatility?

Answer 15

The measure of the ease with which a liquid is converted to a vaporous state

Question 16

What is acidity?

Answer 16

A measure of the corrosive tendencies of the oil

Question 17

What is oil foaming?

Answer 17

The measure of the resistance of the oil to separate from entrapped air

Question 18

What is rubber swelling?

Answer 18

The amount the oil will cause a particular rubber compound to swell

Question 19

What is oxidation and thermal stability?

Answer 19

The ability of the oil to resist the formation of hard carbon and sludge at high temperatures

Question 20

What is coking?

Answer 20

The amount of carbon residue remaining in the oil after being subjected to extreme heating

Question 21

Four main types of aviation fuel?

Answer 21

Jet A1
Jet A
Jet B
JP 5

Question 22

What is the most common fuel type for jet engines in Europe?

Answer 22

Jet A1

Question 23

What is the most common fuel type for jet engines in America?

Answer 23

Jet A

Question 24

Jet B flash point?

Answer 24

-20 degrees Celsius

Question 25

Why is JP5 preferred for military aircraft?

Answer 25

Very high flash point of plus 65 degrees Celsius. Safe to handle Low freezing point at -48 degrees Celsius

Question 26

Jet A and Jet A1 densities?

Answer 26

Have the same density of 0.81kg/ltr at a temp of 15 degrees c

Question 27

Jet A and Jet A1 densities?

Answer 27

Have the same density of 0.81kg/ltr at a temp of 15 degrees c

Question 28

Two conditions of water being in fuel?

Answer 28

Can be dissolved into fuel (invisible) Can be suspended in fuel, visible as small droplets or water bubbles

Question 29

Why is water a hazard in fuel?

Answer 29

Can cause ice build up Supports corrosion Can cause flame outs Microbial growth in fuel tanks

Question 30

Types of fuel additives?

Answer 30

Anti icing Anti microbial Anti oxidants Static dissipator Corrosion inhibitor Metal de activator

Question 31

What do anti oxidants do?

Answer 31

Prevent formation of gum deposits on fuel system components caused by oxidation of the fuel in storage

Question 32

What are metal de activators?

Answer 32

Suppress the catalytic effect that some metals, particularly copper have on fuel oxidation

Question 33

Can open containers be reused of synthetic oil?

Answer 33

No as it will have absorbed moisture

Question 34

Can synthetic oil brands be mixed?

Answer 34

No as they may not be compatible

Question 35

How to deal with small and large fuel spills?

Answer 35

If it’s small commercial absorbing agents can be used If it’s larger then it must be washed away with plenty of water

Question 36

If fuel is ingested what should you do?

Answer 36

Do not induce vomiting Drink 250ml of water Obtain medical attention immediately

Question 37

How do deal with fuel spilt or leakage?

Answer 37

First stop the leakage flow Then add a binding agent to fuel spillage

Question 38

Is refuelling allowed when aircraft engines are running?

Answer 38

No