Fuel System

Question 1

How is Fuel in the Center Wing Tank (CWT) scavenged?

Answer 1

By 4 Jet pumps in Main Tanks 2 & 3.

Additional Information:
Scavenge begins when Main Tanks 2 or 3 fuel drops to below 27.2T.

Question 2

Which Crossfeed valves are controlled by system logic when T/O Flaps are set?

Answer 2

Crossfeed Valves 2 & 3.

Question 3

During the Before Start Procedure, at what CWT quantity are you required to set the CWT Pumps on? (747-400, 747-8 & LCF)

Answer 3

747-400 & 747-8: 7.7T or more.
LCF: 17,000lbs or more.

Question 4

Main tank 2 & 3 Override Jet Pumps can operate to a Standpipe level of Approximately how much? (747-400, 747-8 & LCF)

Answer 4

747-400: 3.2T
747-8: 3.45T
LCF: 7000lbs

Question 5

Describe how the fuel quantity indication changes upon termination of fuel Jettison?

Answer 5

The ‘Fuel to Remain’ value changes to white, and Flashes for 5 seconds.

Question 6

How does CWT fuel scavenge?

Answer 6

747-400 & 747-8: 4 Jet Pumps in MT 2 & 3.
LCF: CWT Electric Pump into M2 Tank, when fuel quantity in either MT 2 or 3 is below 40,300lbs.

Question 7

What happens when you select the Fuel Jettison Switch to A or B? (2 Items)

Answer 7

Arms the Jettison Selector, and
Displays Preselected Fuel to Remain on EICAS.

Question 8

What is the impact on the aircraft with excessive fuel imbalance? (3 Items)

Answer 8

Increased Drag,
Reduced Fuel Economy, and
Adversely affects CG.

Question 9

What is the impact on the aircraft with excessive fuel imbalance? (3 Items)

Answer 9

Increased Drag,
Reduced Fuel Economy, and
Adversely affects CG.

Question 10

When do the FSMC’s open the reserve Transfer Valves? (747-400/-8/LCF)

Answer 10

747-400: When MT 2 or 3 decreases to below 18.2T
747-8: When MT 1 or 4 decreases to below 6.1T
LCF: When MT 2 or 3 decreases to below 40,200lbs.

Question 11

In which tank is Fuel Temperature measured?

Answer 11

MT 1.

Question 12

How would you handle am excessive fuel imbalance situation?

Answer 12

By following the QRH.

Question 13

Which Fuel tanks do RSV 1 & 4 transfer to on the 747-8?

Answer 13

MT 1 & 4.

Question 14

On the 747-8, at what fuel quantity will the fuel Jettison complete operations with the selector in MLW?

Answer 14

MLW + 3T.

Question 15

During Fuel Jettison operations on the LCF, transfer valves open when fuel quantity in MT 2 or 3 decreases to what quantity?

Answer 15

20,000lbs.