11.10 Fuel Flashcards
What are the 4 most common turbine engine fuels?
. Jet A1
. Jet A
. Jet B
. JP5
What duel is most common in Europe and America?
Europe = Jet A1
America = Jet A
What are the freezing and flash points of JETA1?
Flash point = 38 degrees C
Freezing point = -47 degrees C
What is the freezing and flash point of JET A?
Flash point = 38 degrees C
Freezing point = -40 degrees C
Define flash point
The lowest temperature at which the fuel creates just enough vapours for it to become inflamed
What are the main requirements for turbine engine fuel?
. Low freezing point
. Low flash point for ignition but high enough for safe handling
. Good lubrication
. Low tendency to vapour at High altitudes
. Low tendency to carry water
. Widely available
What are the two different conditions that water can be presents in fuel tank?
. Dissolved - totally invisible
. Suspended - visible as small droplets or milky appearance or bubbles
How can you detect water in fuel tanks?
. Syringe test cartridge
. Filter changes colour
What are the different types of fuel tanks?
. Reserve tanks
. Auxiliary tanks
. Integral tanks
What is the purpose of an auxiliary fuel tank?
Optional tanks installed in cargo compartment to further increase aircraft range
Where are integral tanks found?
Found in wings, fuselage, horizontal stabiliser
Most common
What is the main advatange of an integral fuel tank?
Saves weight because the fuel is in parts of the aircraft structure
What do we use to seal integral tanks?
Fillet seal
(Two plates join together with cap seals over bolts etc)
How do you prevent fuel flowing out of collector boxes?
Flap baffle check valves
(Allows movement in one direction only)
How you access the fuel tanks?
Access panels
What are the three most used fuel sensors?
. Float switch
. Thermistor type sensor
. Single point sensor
How do you prevent sparks on access door and aircraft structures?
Kint aluminium gasket
(Bonding)
How do you ventilate fuel tanks?
Passing air around fuel tanks then releasing air to atmosphere
For stab tank, ram air is circulated
What is the main purpose of draining fuel tanks?
. To remove water
. If needs maintenance
What are the two types of drain valves?
. Direct valve
. Indirect valve
What is the difference between direct and indirect drain valves?
Direct . Installed at lowest point of tank
Indirect. Due to design, drain valves that are not at the lowest point of fuel tank
What do water scavenge systems do?
Used to remove water collected in the tank by getting sucked into a jet pump
What is the purpose of the fuel tank vent system?
Allows air in fuel tank to escape during refuelling and air to come in when fuel is being used.
Protects from over and under pressuring
During flight what is air for fuel system pressurisation collected by?
NACA air inlet
Where is NACA air intake?
Lower surface of the wing (triangle)
What are the two methods of refuelling?
. Gravity refuelling
. Pressure refuelling
What are the two main disadvantages of gravity refuelling?
. Takes so long
. Easy to spill
What PSI do you pressure refuel at?
50 PSI
What are the three modes of pressure refuelling?
. Manual
. Automatic
. Override
In what mode can you control refuelling from cockpit?
. Automatic mode
What is used to power supply for refuelling?
. External power
. APU
. Battery
How do you prevent overfilling if system fails?
Fuel quantity probes to monitor the fuel levels
How many boost pumps do major fuel tanks have?
2 boost pumps
Making it fail safe
What are the two methods of defuelling and which one is preferred?
. Pressure defuelling - preferred
. Suction defuelling
What do we use to pressure defuel?
25- 50 PSI output pressure of boost pumps allows for fast defuelling
What is the maximum suction required for defuelling from bowser?
10- 15 PSI
Is fuel transfer done automatically or manually?
ALWAYS done manually
What does a jettison system allow?
Allows pilot to dump fuel overboard
( if emergency, or prevent overweight landing)
What are the special jettison nozzles called?
Anti- corona outlets
Where is the total amount of fuel located?
ECAM or EICAS displays
What can the centre or gravity be referred as?
Percentage of mean aerodynamic chord
When is the fuel control computer bit operational?
At take off and landing
When is aircraft’s centre of gravity determined?
By manufacture upon delivery
What is the use of a trim tank system?
Used to increase the efficient if an aircraft in flight, reduces fuel consumption
What is the purpose of fuel scavenge system?
Reduces the amount of non usable fuel in the tanks
When is fuel transfer allowed?
From reserve tanks to inner main tanks in equal amount, simultaneously
When all fuel pumps are the same type what type of valve would you use?
Sequence valve
What are the two methods of pressure controlled fuel feeds?
. High pressure pump
. Sequence valves (low pressure)
Where is the engine fuel shut off valve found?
On engine fire panel
What else can a fuel feed system do, in terms of a possible emergency?
Enables isolation of any consumer from the system
What does the fuel recirculating system do?
Fuel is used to cool inter grated drive generator and engine oil system. Then passed back to fuel tank
What is the main purpose of fuel feed system?
Ensure proper fuel supply to engine and APU
What has to be open for power up of refuelling system?
When panel door is open, a switch is activated and system is powered up
When would you use override mode?
An alternative procedure if electrical power for refuelling is unavailable
How does automatic mode refuel?
Fuel control computer take preselected and works our correct distribution
What must you do when in manual mode?
Calculate the fuel distribution before refuelling
What are the main 5 components of a refuelling system?
. Refuelling couplings
. Refuelling manifold
. Refuelling valves
. Diffusers
. Refuelling control panel
What happens if a dangerous level of pressure is reached?
Relief valves open
How are drain valves normally operated?
Normally manually
But in difficult to reach places they may be electric
How do you know of there is a fuel leak?
By a leak monitor connected to the drain valve
If a fuel tank is large enough for someone to clim into, what does it have?
Internal openings
Reduce number if external panels, therefore reducing leak points
