Fuel Flashcards
Where are the controls and indicators found?
- Overhead fuel panel
- Refuelling control panel:
A) 1 per wing (allowing fuelling via either side)
B) 1 x right fuselage (just in front of right wing)
3) ECAM Display
Where are the fuel tanks?
- Left wing tank (outer and inner)
- Centre tank
- Right wing tank (outer and inner)
What is the total usable fuel capacity?
24,209 litres (with a 2% allowance to allow for expansion due to temperature rising)
What are fuel transfer valves and where are they?
- 2 x Transfer valves per wing
- Open (both left and right wings) when fuel quantity in either inner tank reaches approximately 750kg
- When open - fuel flows evenly by gravity into the inner tanks
Note: during steep turns or accelerations - low fuel warning ECAM message may be triggered
What are Vent Surge Tanks?
- Hold overflow fuel to prevent spillage when on ground and during take off
- Fuel that enters the surge tank is moved to its proper wing tank via scavenge jet pumps
- If surge tank overloaded - fuel is dumped overboard via a vent duct
What is the Vent Tank System used for?
- Equalises pressure between the inside of the fuel tanks and the ambient air
- Over pressure protectors in the form of burst disks are installed in the tanks which break at a specific limit if there is a blocked vent (3 per wing and 2 for centre tank)
- The LH vent surge tank vents the LH wing tank and centre tank
- The RH vent surge tank vents the RH wing tank
How does the Tank Interting System work?
- CSAS (Conditioned Service Air System) converts engine bleed air to correct temp and pressure
- That bleed air is then sent to the IGGS (Inert Gas Generation System) to trap nitrogen and create oxygen depleted air
- The oxygen depleted air is then sent to the centre fuel tank (mitigating the risk of fire in the centre tank)
How is the IDG (Integrated Drive Generator) cooled?
- Some fuel in tank is sent to IDG to cool IDG oil
- Cooling occurs through the heat exchanger (oil cooled / fuel heated as a result)
- Fuel is then returned to the tank (or if too hot it is sent to FRV (Fuel Return Vavle) and HP pump to be cooled (by mixing the hot fuel with the LP cooler fuel)
- This cooling system is controlled by the FADEC using signals from the FLSCU
What is the fuel cross feed valve and what does it do?
- Normally the LH and RH tanks are separate and isolated (I.e cross feed valve closed)
- X feed valve open connects the two tanks
- X feed is operated by two motors (each supplied by a different power source)
How many fuel pumps are there?
4 total:
a) 2 per inner wing tank
b) 2 in the centre tank
Note: another 2 JET pumps for pumping fuel from centre to inner tanks
What is the normal fuel feed sequence?
Inner tanks feed fuel to the engines. The tanks empty in the following sequence:
1A) Inner tanks use 500kg to make room in tank
1B) The centre tank. Fuel transfers into the inner tanks (via jet pumps). One centre empty (note centre fuel pumps still continue 5 mins once empty)
- The Inner Tanks. Each inner tank empties down to 750kg
- Outer tanks. Fuel transfers into the inner tanks (via transfer valve)
How is fuel supplied from the fuel tank to the engine?
Tank - fuel tank pump - lower pressure valve - engine
How is fuel supplied in the event of low pressure (e.g fuel pump issue)
Utilises gravity. Suction Valve in the tank. Lack of pump pressure causes valve to open and engine suction extracts fuel from the tank
Note: No suction valves in centre tanks (I.e inop if pressure problem)
How is APU supplied with fuel?
- Left side fuel system
- APU also has its own pump which sends fuel to APU LP Valve
Note: APU Valve controlled via a) APU MASTER SW b) APU FIRE pb c) APU SHUT OFF
How does the Fuel Quantity Indication System work?
- Two channel Fuel Quantity Indicating Computer
- FQIC is fed information by:a) several Fuel quantity probes in the tanks
b) 1 x Candensicon per tanks —
(measures density)
c) 1 x Capacitance Index Compensator per tank (redundancy for if candensicon fails)
FQIC provides information about fuel quantity and its weight in kg
CH1 and CH2 do the calculations. However only CH1 used (unless it fails) and the CH2 is used
Fuel Level Sensing System.
Components?
- Fuel level sensors
- Fuel temp sensors
- 2 x Fuel Level Sensing Control Units (FLCU)
How does it work?
FLCU monitors temp/level and sends commands to FADEC (e.g to close a FRV if fuel too hot when returning from IDG)
Manual Magnetic Indicators (MMI)
Secondary method for determining fuel quantity on the ground (when ECAM indications are unserviceable).
Tables are used to calculate fuel quantity
Procedure for refuel
- Done auto or manual
- Out tanks fill first, then the inner tanks (if centre tanks used - the outer and centre tanks fill at the same time)
- Monitored by the FQIC
Overwing refuelling
TBC if covered in class
Fuel on take off
Centre Jet pumps must be shut off until slats refracted (occurs automatically with AUTO selected)
Maximum fuelling pressure and defuelling pressure?
Fuelling = 50 PSI
Defuelling = 11 PSI
What does normal fuel distribution look like in the tanks?
- Fuel in LH and RH tanks should be balanced
- Outer tanks should be full
- If fuel in centre tank - wing tanks must be full
If fuel imbalance in flight (e.g lower fuel in LH tank) - how is this corrected?
- Select X FEED pb to ON
- Turn off the LH Fuel pumps (1 and 2)
- When balanced - turn pumps 1 and 2 on and turn X FEED off
(NOTE: no requirement to correct the in balance until receive an ECAM Advisory)
Fuelling order (during auto)
- Fuel goes into centre and outer tanks simultaneously
- When outer tank full - fuel overflows into the inner tanks
Can the aircraft be fuelled with no external power?
Yes - via the Hot Batt Bus
What does “OPEN” (green light) on the X FEED pb mean?
The cross feed valve is FULLY open
Minimum fuel for take off
1,500kg
Where does the FOB figure derive from?
FQI (Fuel Quantity Indicator)
Remember the FQI FOB is entirely separate to any low level fuel warnings
How do you close the LP fuel pumps?
- ENG MASTER switches off
- FIRE pbs
Where can you see the fuel temps?
SD (Fuel Page)
When does the “LOW LEVEL TK” message show?
- When the low level sensor is dry in an inner fuel tank [750kg]
- If low level in one tank (left) very likely the same in the right tank and so both tanks start to draw fuel from outer tanks at same time
- Once outer tank fuel used - left with 750kg x 2 (thinking about final reserve now)
