Fuel

Question 0

Boost pumps powered?

Answer 0

Left pump DC battery bus for starting w/o ext power

Right pump powered by DC bus 2

Question 1

AUTO XFLOW INHIBIT msg

Answer 1

The fuel automatic crossflow is inhibited

Question 2

Fuel valve check test

Answer 2

Both pumps off

L&R amber messages and R low fuel pressure message

Question 4

What is the purpose of the boost pumps

Are they required for engine start?

Answer 4

-Transfer from the collector to the engine
-Backup to the main ejectors
-Provide fuel pressure during engine start
No

Question 4

How are the boost pumps powered

Answer 4

DC powered

Question 5

How does APU get fuel

Answer 5

X-Flow APU pump gets fuel from both tanks. If not working then it uses the negative gravity relief valve

Question 6

Where is the temperature of the fuel measured

Answer 6

Left wing and the fuel line of each engine

Question 7

How does fuel stay in each tank during maneuvers

Answer 7

one way check valves

Question 8

When will the left or right wing fuel tank quantity turn amber

Answer 8

• Total fuel quantity 900 lbs or less

- imbalance of more than 800lbs

Question 9

What powers the fuel ejectors

Answer 9

Motive flow from the engine driven pump

Question 10

How is fuel transferred from wing tanks to collector tanks

Answer 10

Scavenge Ejectors

Question 11

How is fuel driven from the Collector tank to the engine driven fuel pump

Answer 11

Main ejector pump through motive flow which is provided by the high pressure of the engine driven fuel pump

Question 12

What do transfer ejectors do?

Answer 12

Transfer fuel from the center tank to the wing tank

Question 13

How is the fuel heated

Answer 13

Fuel oil heat exchanger in each engine

Question 14

What happens if a fuel filter is clogged

Answer 14

The low pressure sends EICAS message and the filter is then bypassed

Question 15

What are the 2 methods of to cross flow fuel

Answer 15

• Powered cross flow (automatic or manual)

- Gravity cross flow

Question 16

Explain the negative gravity relief valve

Answer 16

Spring loaded valve that allows pressurized fuel from the right engine fuel feed manifold to feed APU

Question 17

What is the function of the XFLOW/APU pump

Answer 17

• Supply fuel to the APU

- Perform cross flow operations

Question 18

When do you get a fuel imbalance message

Answer 18

800lb difference between wing tanks

Question 19

When does automatic crossflow initiate

Answer 19

When there is a rule imbalance of more than 200lbs

XFLOW/APU fills the low side to 50lbs above the other side

Question 20

When does bulk fuel temp turn amber

Answer 20

-40c and below

Question 21

When does fuel feed temp turn amber

Answer 21

5c and below

Question 22

When does center tank quantity indicate green

Answer 22

10lbs or more, below this it indicates white

Question 23

When is negative gravity relief valve used

Answer 23

-when the XFLOW/APU pump fails (deferrable)
-when a negative gravity situation exists
(not indicated on fuel synoptic page)

Question 24

What are the 6 ejector pumps

Answer 24

• 2 Main ejectors
• 2 Scavenge ejectors
• 2 Transfer ejectors

Question 25

Where is fuel temp shown

Answer 25

synoptic page