Systems - Fuel

Question 1

When the fuel jettison switch is armed, what is displayed on the EICAS?

Answer 1

Fuel to remain at max landing weight

Question 2

If you wish to dump below max landing weight, what must you do?

Answer 2

Manually select the fuel quantity

Question 3

What is the minimum fuel to remain you can dump to?

Answer 3

Roughly 11,500 lbs in each main tank

Question 4

How much flying time does this equate to?

Answer 4

About 2 hours

Question 5

Why do we have 2 cross feed valves?

Answer 5

Redundancy

Question 6

During preflight with all fuel boost pumps off you notice the left forward boost pump pressure light extinguished.
Why?

Answer 6

APU is using the FWD left main AC pump

Question 7

Is there any other fuel pump available to the APU?

Answer 7

Dedicated DC pump in the left main tank

Question 8

With full tanks what is the sequence of fuel usage?

Answer 8

Center burn off first, then the mains

Question 9

How does the fuel scavenge system work?

Answer 9

After center tank fuel pumps are deenergized scavenge pumps transfer fuel into the main tanks

Question 10

Where can you find jettison time displayed?

Answer 10

• EICAS (replacing fuel temperature)
• FUEL synoptic page

Question 11

Is there a way to tell if the fuel is approaching the fuel freeze point?

Answer 11

Fuel temp turns amber

Question 12

When would an expanded fuel quantity display appear on the EICAS?

Answer 12

During and imbalance condition or during crossfeed

Question 13

What are fuel imbalance indications?

Answer 13

• EICAS MSG
• expanded display
• amber pointer to the lowest tank

Question 14

How is a “wrong way” fuel cross feed indicated?

Answer 14

Pointer flashes

Question 15

Is it possible to dump fuel on the ground?

Answer 15

Yes it is

Question 16

How is the fuel heated?

Answer 16

Prior to entering the engine it passes through an air/oil cooler then an oil/fuel heat exchanger

Question 17

At what imbalance amount does the expanded fuel display appear?
When does it go away?

Answer 17

• When main tank fuel differs by more than a 1000 lbs
• Pointer flashes and disappears after the fuel is within 200lbs

Question 18

Where can the actual fuel temperature and minimum fuel temperature be found?

Answer 18

FUEL synoptic

Question 19

With center fuel pumps on, why is center tank fuel used before fuel from the main wing tanks?

Answer 19

Higher output fuel pumps

Question 20

When main tank fuel pressure is low, how does the engine receive fuel?

Answer 20

Suction

Question 21

What fuel condition generates an FMC message INSUFFICIENT FUEL?

Answer 21

Fuel at destination is below programmed fuel in performance