Fuel And Icing Flashcards
Which type of engine uses which type of fuel?
Aviation gas (avgas)- piston Turbine fuels- gas turbine
What are the 3 avgas grades and colour codings?
80- red
100- green
100LL- blue
What is knocking?
When the fuel/air mixture does not ignite properly and air pockets outside of the normal combustion front explode instead. This creates shockwaves that creates a metallic pinging sound and increases the cylinder pressure.
What are the 3 turbine fuels and their freezing points in Celsius?
A- -40
A1- -47
B- -50
Can piston engine use turbine fuels?
No
Can a gas turbine engine use avgas fuels?
Yes but only for limited periods to stop a decrease in engine efficiency
What colour are turbine fuels?
Clear or straw
What are the two type of refuelling/defuelling?
Gravity or over wing
Pressure
How is pressure refuelling done?
Fuel is pumped into the tank from a refuelling coupling at high rates at around 50psi
What is the fill rate of pressure refuelling?
1000 gallons a minute
How does pressure defuelling work?
Similar to pressure refuelling but with a negative pressure around -11psi usually. This is done through pumps on the bowser or the fuel pumps themselves.
What is don with the drained fuel after a defuel?
Put in a dedicated bowser in case of a microbiological or water contamination
What is the fuelling zone area?
6m from the aircraft and fuelling equipment.
What is is the minimum distance no smoking signs should be placed from the fuelling area?
15m
Why should refuelling be done outside?
To minimise the risk of a fire due to high concentrations of inflammable vapours
What should be bonded together for fuelling operations?
Aircraft to ground
Bowser to aircraft
Bowser to ground
Refuel head to aircraft
What should be done to help avoid contamination of the fuel causing issues during flight?
Regularly check the fuel for water and microbes.
Using a filter for over wing fuelling to avoid contamination in dusty climates
What should and shouldn’t be near or in fuelling zones?
Fire extinguishers- in
Sparks/ignition sources- out
Should electrics be on during fuelling operations?
It doesn’t matter, as long it is not switched on or off during the operation
Where should a GPU be positioned in relation to fuelling operations?
As far away from fuel ports and vents as possible
How should fuel spillages be dealt with?
Cleaned up immediately, NOT emptied into the drains, warning signs placed at spillage area until vapours have cleared
How should the bowser be set up?
Facing away from the aircraft with a clear exit path, earthed to the aircraft and ground
Should chocks be at the wheels during refuelling?
Yes but further away from the wheels to allow for expansion
What dictates the cold weather procedures of a company?
Climatic conditions of the location
Available equipment and materials
Cold weather experience
Should sand and salt be used for clearing snow around aircraft?
No, keep it away from aircraft as much as possible
What should be done after flight in relation to the galleys and drinking water systems during cold weather?
Drain fluids and clean both systems, including toilets
Remove any food from the galley
What condition should the aircraft be left in after flight in cold weather?
Brakes off when parked
Covers installed on probes, engines, etc.
Landing gear locks installed
What should be done when draining oil from piston engines?
Do it while it’s hot
When should antifreeze be applied after flight and where?
If the aircraft is wet
Underside of covers before fitting, after ice melted and drained from ports
What should be done before flight in cold weather?
Remove covers Remove ice and snow Check heaters Use blow heaters Normal preflight checks Preheat engines
What should be done if the aircraft does not take off in a certain time period during cold weather?
Clear off any ice/ snow and preheat the engines again
What is hoar frost and how does it occur?
White feathery ice that builds up on the surface
Occurs when on the ground
What issues can hoar frost cause?
The weight of the deposit is not serious, but could interfere with areas such as airflow and the working of free moving parts
What is rime ice and when does it occur?
An opaque rough deposit less dense than glaze ice
Is light and porous with large amounts of trapped air in them
Occurs on the ground in freezing fog conditions that cause the water particles to freeze with little expansion
What issues could be caused by rime ice?
Could interfere with airflow and choke orifices for areas such as carburettor or intakes
What causes debris ice?
Slick/snow being blown onto the aircraft from multiple potential causes such as wind, passing vehicles, etc.
What is glaze ice and how does it occur?
Dense glassy ice
Occurs during freezing rain conditions when airframe is below freezing point
What are the effects of glaze ice on aircraft?
Weight increase
Aerodynamic disruption
Can take chunks out of the aircraft when it brakes off due to how well it sticks
How can pack snow affect aircraft?
Can form glaze ice on top due to the moisture in the snow
How are the aerodynamics affected by ice build up?
Loss of lift
Increased drag
Decrease in propeller efficiency
How can ice affect control surfaces and wing loading?
Increased load on wings due to more weight from the ice
Loss of control- control surfaces can’t move
Increased risk of fluttering on control surfaces
What are some other effects caused by ice build up?
Reduced stalling speed Loss of vision Loss of stability- off balanced CofG Propeller vibration Malfunction of instruments Ice debris damage
How are de-icing fluids normally applied to aircraft?
Heated
What sort of fluids would be used for de-icing?
Heated water
Newtonian fluids
Non-Newtonian fluids
Mixtures of water and either Newtonian or non-Newtonian fluid
Why would antifreeze be applied to aircraft?
To prevent a build up of ice or snow for a limited period of time
What fluids could be used for antifreeze layers?
Newtonian fluids
Non-Newtonian fluids
Mixtures of water and either Newtonian or non-Newtonian fluid
When des the holdover time begin?
At the beginning of the application of the antifreeze
What are the 2 types of de-/anti-icing?
One step
Two step
What is one step de-/anti-icing?
The aircraft is deiced and he fluid left gives a limited anti ice protection
What is two step de-/anti-icing?
The aircraft is deiced and then has a layer of antifreeze applied
What factors can determine if de icing is required or if icing could happen?
Temperature of fuel in wing tanks (icing)
Weather conditions (deicing)
Flaps and slats not fully retracted (deicing)
When doing a preflight inspection what is recommended?
Inspecting critical surfaces by hand
Do from a position that covers all surfaces clearly
Which fluid type is mainly used for de icing?
Type 1
80% of type 1 fluids must contain what?
Mono ethylene-glycol
Diethylene-glycol
Monopropylene- glycol
A mixture of the above
What does the other 20% of type 1 fluid contain?
Inhibitors to restrict corrosion and increase flash point
What does at least 50% of types 2 and 4 contain?
Mono ethylene-glycol
Diethylene-glycol
Monopropylene- glycol
A mixture of the above
What does the other 50% of type 2 and 4 fluids contain?
Inhibitors and thickening agents
Which types of de icing fluid has the longer holdover time?
Types 2 and 4
What factors cloud shorten the hold over time for an aircraft?
Severe weather Strong winds/jet blasts Application method Fluid age and condition Wing temp being lower than OAT
What information will always be contained in the anti-icing code?
Type of fluid
Ratio of water/fluid mix
Time application began (preferably local)
What does the octane number represent?
Resistance to knocking
What is the downside to one step de/anti icing?
The fluid gives limited protection against icing.
Which type of de/anti icing does not require the ratio of fluid to water in its code?
Type 1
Can radio and radar systems operate during fuelling operations?
No
