Module 15.9 Lubricants and fuels

Question 1

What are the drawbacks of mineral oils?

Answer 1

Lack stability and suffer from excessive volatility and thermal degradation at high temperatures

Question 2

Ester based synthetic oils are now referred to as what?

Answer 2

Third generation oils

Question 3

What are the functions of engine oil?

Answer 3

• Lubrication
• Cooling
• Cleaning
• Corrosion protection

Question 4

What are the types of synthetic oils and uses?

Answer 4

Type 1 - older aircraft
Type 2 - modern GTE
Type 3 - specialised aircraft, jets

Question 5

What are the advantages of synthetic oils?

Answer 5

• Better viscosity
• Better thermal stability
• High pressure resistance

Question 6

What is viscosity index?

Answer 6

The effect that temp has on the viscosity

Question 7

What is viscosity?

Answer 7

Internal resistance of fluid against deformation/flow

Question 8

What is the pour point?

Answer 8

Lowest temperature oil will visibly move

Type 2 - -57℃

Question 9

What is the flash point of type 2 oils?

Answer 9

250℃

Question 10

What is a feature needed for oil when between moving components?

Answer 10

Pressure resistance

Question 11

What happens to oil when it reacts with oxygen?

Answer 11

It gets thicker

Question 12

Acidity is a measure of what?

Answer 12

The oil’s corrosive tendencies

Question 13

What is oil foaming a measure of?

Answer 13

Resistance of oil to separate from entrapped air

Question 14

Oil can cause rubber to do what?

Answer 14

Swell

Question 15

What metal is particularly susceptible to oil corrosion?

Answer 15

Copper

Question 16

What is coking?

Answer 16

Amount of carbon residue in the oil after extreme heating

Question 17

What are the four types of turbine fuel?

Answer 17

• Jet A
• Jet A1
• Jet B
• JP5 (military application)

Question 18

What is the flash point and freezing point for JP5?

Answer 18

+65℃ - flash point
-48℃ - freezing point

Question 19

What is the flash point of jet B?

Answer 19

-20℃

Question 20

Where is jet A and jet A1 used?

Answer 20

Jet A - Europe
Jet A1 - America

Question 21

What are the main turbine fuel requirements?

Answer 21

• Low freezing point
• Low flash point for good ignition, but high enough to ensure safe handling

Question 22

What temp should max viscosity be at?

Answer 22

-20℃

Question 23

Jet fuels tend to carry what?

Answer 23

Water, dirt and micro-organisms

Question 24

What are the two conditions water can be carried in, in fuel?

Answer 24

• Disolved
• Suspended

Question 25

The interface between water and fuel promotes what?

Answer 25

Micro-biological growth

Question 26

What is the density of Jet A/A1at 15℃?

Answer 26

0.81 kg/Ltr

Question 27

What are two main reasons additives may be added to fuel?

Answer 27

• Anti-ice
• Anti-microbial

Question 28

What is a fuel anti-ice additive?

Answer 28

Prist

Question 29

What are some common additives in use?

Answer 29

• Anti-oxidants
• Static dissipator
• Corrosion inhibitors
• Metal deactivators

Question 30

Are synthetic oils storage stable?

Answer 30

No

Question 31

Can open containers of synthetic oil be re-used?

Answer 31

No

Question 32

Can you mix different brands and types of oil?

Answer 32

No

Question 33

Fuel leaks are caused by what?

Answer 33

• Refuelling malfunctions
• Aircraft damage

Question 34

Where do refuelling leaks usually occur?

Answer 34

At vent tank openings