M15.9 Flashcards
What are the main tasks of oil on modern jet engines?
- lubricating
- cooling
- cleaning
- corrosion protection
Where is mineral oil normally used?
Only on piston type engines
Where are synthetic oils used?
On jet engines
What are the different types of synthetic oils?
- type 1 (used on old engines)
- type 2 (used on modern engines)
- type 3 (used on special aircraft)
What are the advantages of synthetic oils?
- Better viscosity
- better thermal stability
- high pressure resistance
Can you mix synthetic oils?
No
What is the viscosity index?
The effect temperature has on the viscosity of the oil
What does a high viscosity index number indicate?
Viscosity least affected by change in temperature
What are modern oils measured in and what temperature?
m2/s at 100C
What is pour point?
The lowest temperature that oil will move in a 31.75mm test tube horizontally for 5 secs
What is fire point?
The lowest temperature that oil will ignite and burn for 5 secs
What is meant by volatility?
The measure of the ease in which liquid converts into a vapour
What is acidity?
A measure of the corrosive tendencies of the oil
What is oil foaming?
The measure of the resistance of the oil to separate from entrapped air
What is rubber swelling?
The amount of oil that will cause rubber to swell
What is oxidation and thermal stability?
The oil resistance to formation of hard carbon and sludge at high temperature
What is corrosiveness?
The effect oil has on metals
What is coking?
The amount of carbon residue remaining in the oil after extreme heating
What type of fuel is most commonly used in commercial engines?
jet A and jet A1
What is jet A and jet A1 manufactured or refined from?
Crude oil petroleum
What will fuel normally be made from?
16% hydrogen and 84% carbon with small amounts of impurities
What are some of the impurities of fuel?
Sulphur, water, nitrogen
What are the characteristics of jet A1 fuel?
- flash point of 38C
- freezing point of -47C
- specific gravity of 0.775-0.83
- most commonly used in Europe
- USA call it JP 1A
What are the characteristics for jet A fuel?
- flash point of 38C
- freezing point of -40C
- specific gravity of 0.775-0.83
- most commonly used in America
- USA call it JP1
What are the characteristics of jet B fuel?
- flash point -20C
- freezing point -58C
- specific gravity of 0.751-00.802
- military equivalent is JP4, F40, Avtag
What are the characteristics of JP5 fuel?
- flash point of 65C
- Freezing point of -48C
- preferred by the military because of the high flash point
Why must type of fuel used be record after refuelling?
Because each fuel type has different handling and operating traits
What is the caloric value of fuel?
18,400 Btujlb
What is meant by additives of fuel?
Maximum anti-oxidants and static dissipator
What will happen to fuel the higher the altitude?
The ambient pressure decreases which cause fuel to vaporise
What is fuel density of jet A and jet A1?
0.81kg/ltr at 15C
What is fuel density of jet B?
0.78kg/ltr at 15C
What is fuel density of JP5?
0.83kg/ltr at 15C
Why are fuel system icing inhibitors used in fuel?
To prevent ice build up in the fuel
Why are metal de-activators used in fuel?
They suppress the catalytic effect of some metals
Why are biocide additives used in fuel?
To prevent microbiological growth
What is fire handling safety divided into?
- fire prevention
- fire extinguishing
- personal safety
What must not take place whilst refuelling or defuelling takes place?
Filling or charging of oxygen bottles
Why must you check the shelf life of synthetic oils?
They’re not storage stable
Why cant you reuse open synthetic oil?
Because its hygroscopic (collects air moisture)
What will long exposure to synthetic oils cause?
Dermatitis
What should be done if synthetic oil is ingested?
Do not induce vomiting and drink 250 ml of water
How long should you wash your eye for if fuel is in your eye?
10 mins
How are fuel leaks caused?
Refuelling malfunctions or by damage to the aircraft
When entering a fuel tank your clothes must be made from what?
Cotton
When an you enter a fuel tank without a full face mask?
If the tank is considered health safe
What is category 1 access to a fuel tank?
You have direct access but cant fit inside
What is category 2 access to a fuel tank?
You have direct access and can get inside
What is category 3 access to a fuel tank?
No direct external access but can get in
What is category 4 access to a fuel tank?
Can only be entered via internal openings which cannot be rescued from
How would you get someone out of category 4 tank area?
Mechanical cutters
