Fuel System

Question 1

How is Center Wing Tank fuel scavenged?

Answer 1

Scavenged by 4 jet pumps pumping into main tanks 2 and 3.

Scavenge begins when main tank 2 or 3 decrease to approx. 27.2kg

Question 2

Which crossfeed valves are controlled by FSMC logic when setting T/O flaps?

Answer 2

Crossfeed valves 2 and 3

Question 3

During the Before Start procedure, at what center wing tank quantity are you required to select the center wing pumps on?

Quantity in lbs for LCF?

Answer 3

7,700 kgs or more in CWT

17,000 lbs or more in CWT

Question 4

Main tank 2 and 3 override/jettison pumps can operate to a standpipe level of approximately ___kgs (400) _____ (LCF) and ____kgs (-8) of fuel remaining in each tank?

Answer 4

3,200 kgs
7,000 lbs
3450 kgs

Question 5

Describe how the fuel quantity indication changes upon termination of fuel jettison

Answer 5

• The fuel to remain quantity indication changes from magenta to white
• fuel to remain quantity flashes for 5 seconds

Question 6

How does CWT fuel scavenge in the 400/-8?

Answer 6

CWT fuel is scavenged by 4 jet pumps pumping into main tanks 2 and 3.

*Scavenge begins when main tank 2 or 3 fuel quanity decreases to approximately 27,200 kgs

Question 7

How does CWT fuel scavenge in the LCF?

Answer 7

-CWT electric pump into M2 tank when CWT override/jettison pump has low pressure

• fuel quantity in M2 or M3 is below 4020 lbs

(pump will operate for approx. 2 hours until scavenge pump pressure is low, whichever occurs first)

Question 8

State what occurs when you select fuel jettison switch to A or B

Answer 8

-arms the jettison selector
- displays preselected fuel to remain on EICAS

Question 9

What is the impact on the aircraft with excessive fuel imbalance?

Answer 9

-adversely effects CG
-aerodynamic drag
- fuel economy

Question 10

When do the FSMCs open the reserve transfer valves on the 400,LCF, -8?

Answer 10

400: When main tank 2 or 3 decrease below approx. 18,200kgs

LCF: When main tank 2 or 3 decrease below approx. 40,200lbs

-8: When main tank 2 or 3 decrease below approx. 6,100kgs

Question 11

In which main tank is fuel temperature measured?

Answer 11

Main Tank 1

Question 12

How would you handle excessive fuel imbalance situation?

Answer 12

By opening or closing cross feed valves, turning off and on fuel pump switches (I WOULD USE QRH and SUPPLEMENTARY PROCEDURES) SP.12

Question 13

Which fuel tanks do reserve tank 1 and 4 transfer to on the 747-8

Answer 13

Main tanks 1 and 4

Question 14

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

Answer 14

Maximum landing weight plus 3,000 kgs

Question 15

During fuel jettison on the LCF, transfer valves open when fuel quantity in tanks 2 or 3 decrease to _____ lbs.

Answer 15

20,000 lbs