FUEL SYSTEM Flashcards
How many fuel tanks are there?
3+2
Left, Centre, Right and two surge tanks
How many fuel pumps are there in the system?
7 2 AC driven pumps in the Left tank 2 AC driven pumps in the Right tank 2 AC driven override/jettison pumps in the Centre tank 1 DC driven pump in the Left tank
When is the DC pump operational?
When the AC pump is not powered
It provides fule to the APU until AC power is established
How are the Centre tank pumps different from the Left/Right tanks fuel pumps?
It’s output pressure is higher so the overrides the Left and Right fuel pumps as a supplier of fuel to the engines when fuel is available in the Centre tank
How many Jettison pumps are there and where are they located?
There are 4 jettison pumps
2 in the Centre tank, combined with the normal AC pumps
1 in each outer wing tank
What inputs are used by the FQIS (Fuel Quantity Indicating System) to calculate fuel quantity?
Fuel height and density
Where are the fuel temperature and minimum fuel temperature displayed?
Fuel temperature is shown on the EICAS display and the fuel synoptic.
Minumium fuel temperature is displayed on the fuel synoptic
Where does the minimum fuel temperature originate from?
Temperature entered in the FMS
On the ground with only one power source, how many Centre tank pumps will run?
Only one
On the ground, when will both Centre tanks run?
When there are two power sources available
What happens when the Centre tank is almost empty?
The outer wing tank pumps automatically take over and a scavange pump in the Centre tank transfer any remaining fuel over to the wing tanks
What happens if both tanks pumps output pressure is low?
The Engines can draw fuel from it’s corresponding main tank through a suction feed line that bypasses the pumps
When is FUEL IMBALANCE displayed?
When the main tanks differ more than 500 kg
What is the total fuel capacity for the B777-300ER?
137’500 kg
How can intial “Jettison fuel to remain” value be modified?
By the “FUEL TO REMAIN” selector
