Fuel

Question 1

Function of Fuel apart from Supplying Engine and APU

Answer 1

Cool the Integrated Drive Generator (IDG) Keep the fuel at outer tank for wing bending and flutter relief.

Question 2

Tanks and Pumps

Answer 2

Tanks:

A320 Max Fuel: 18,728 kg

A321 Max Fuel: 18,605 kg, without Additional Center Tank (ACT)

Assuming Fuel Density 0.785 kg/L

A320 and A321: Can be refuelled to maximum capacity, then expand by 2% (20 degC temp rise) without spilling, due presence of Vent surge tank at outboard of each Outer Tank (A320) / Wing Tank (A321). All tanks (including vent tanks) have overpressure protectors.

Pumps:

A320: 2 Pumps at each Inner Wing Tank 2 Pumps at Center Tank Outer Tanks –> Electrical Transfer Valves –> Inner Tank Pressure relief sequence valves ensure Center Tank Pumps deliver fuel preferentially to Inner Tank Pumps Suction valves allow GRVTY FEED from WING TANKS but does NOT allow from CENTER TANK (due NOT installed), in case of inner tank pumps fail.

A321: 2 Pumps at each Wing Tank Center Tank –> Transfer Valves –> Wing Tanks Transfer Valve Opens –> Fuel from the Wing Tank Pumps flow through the jet pump and creates suction –> Fuel moves from Center Tank to related Wing Tanks *Have option of installing up to 2 Additional Center Tanks (ACT) Suction valves allow GRVTY FEED from WING TANKS AND CENTER TANK (Down to 2T Unusable).

A320 and A321: Suction valves allow GRVTY FEED from WING TANKS but does NOT allow from CENTER TANK, in case of inner tank pumps fail.

Answer 3

A320: From CBT:

1. If the engines are fed from the center tank and the wing tanks are full, the center tank pumps automatically shut off.
2. Until approximately 500 kg of the fuel in its associated inner tank has been used (INNER WING TK Quantity

Question 4

Refuelling

Answer 4

Start from Outer Cell, then Inner Cell through a spill pipe. If selected fuel load exceeds the wing tank capacity, the center tank is SIMULTANEOUSLY refueled. Refuel could only be done when battery power is available. Wing Tanks could be refueled by gravity where refueling points are at the top of wings. Transfer valves allow defueling through the refuel coupling.

Question 5

Fuel Quantity Indication (FQI) System Fuel Level Sensing Control Unit (FLSCU)

Answer 5

Fuel Quantity Indication (FQI) System Sensors Output: Numerical Quantity entered to Computer Main purpose: To record Fuel Mass (Weight), Control Automatic Refueling Has a set of capacitance probes to measure level and temperature Indicates fuel quantity on refuel / defuel panel Fuel Level Sensing Control Unit (FLSCU) Sensors Output: Wet or Dry Main purpose: To control refuel / defuel / IDG recirculation / Center to Wing Tank Transfer / ACT to Center Tank Fuel Transfer Has Fuel Level Sensors to sense high, low and overflow levels Has Fuel Temperature Sensor to control the IDG cooling recirculation

Question 6

Fuel Tank Inerting System

Answer 6

On center tanks of HSQ - HSU, the system produces an Oxygen-depleted air that goes in the center tank to replace ambient air. Engine Bleed Air –> Conditioned Service Air System (CSAS) for correct Pressure and Temperature –> Inert Gas Generation System (IGGS) to tap Nitrogen Moldcules –> Center Tank with air of less than 12% Oxygen

Question 7

ECAM Fuel Page Indication

Answer 7

Amber line appears across the last 2 digits on Fuel Quantity Indication: FQI is inaccurate. Center Tank Indication Boxed Amber: Both Center Tank Pumps are failed / OFF (A320), Both Center Tank Transfer Valves are failed to open (A321), i.e. Center Tank Fuel Unusable. Outer Tank Indicatin Boxed Amber: Both Transfer Valves fail to open, when the inner tank is at low level, i.e. Outer Tank Fuel Unusable. FOB Boxed Amber (Half Boxed Amber for HSL-HSU, HTJ-HTK): Either one of above Boxed Amber cases occur. Wing Tank Indication in Amber or CTR TK L(R) XFR Pb FAULT Light (A321 only): Associated Wing Tank Overflows.