Fuel System

Question 1

How many fuel tanks

Answer 1

3, left right and center

Question 2

They can all be fueled through…

Answer 2

The single point adapter

Question 3

Which tanks can be gravity fueled?

Answer 3

Only left and right

Question 4

Can the fuel in the center tank go directly to the engines?

Answer 4

No, it has to go to the left or right wing tank first

Question 5

Croosflwo vs transfer

Answer 5

Crossflow = balancing the weight
Transfer    = flowing fuel from one place to another

Question 6

What tank must all fuel flow through

Answer 6

Collector tanks

Question 7

Which tank does the APU draw fuel from?

Answer 7

The left collector tank. This dads to the left tank often having less fuel.

Question 8

Is there a true left and right fuel tank?

Answer 8

Negative. The inside of the wings are the tanks and are sealed with a fuel resistant sealant.

Question 9

What are flapper valves

Answer 9

One way valves on the wing ribs that don’t allow the fuel to flow towards the wing tip during wing low maneuvers.

Question 10

Pressure relief valve

Answer 10

Automatically evacuates fuel if overfilled. Spring loaded. Located on the bottom midpoint of each wing.

Question 11

What do the NACA scoops do

Answer 11

Prevent ice build up and allows the tanks to vent.

Question 12

Fuel system computer (FSC)

Answer 12

Dual-channel computer that monitors and controls the fuel system
Only one channel is active at a time

Question 13

Engine driven fuel pumps

Answer 13

One on each engine. If these fail the engine will fail, there is no backup. More fuel than the engines require is sent to the pump in order to create motive flow.

Question 14

Motive flow ejector pumps

Answer 14

• Operate using motive flow pressure
• Motive flow is created using the excess fuel sent to the engines by the high pressure engine driven fuel pumps
• As fuel flows through the restriction pressure decreases and sucks in more fuel

Question 15

How many flow ejector pumps…

Answer 15

8 total
2 Transfer ejectors
4 Scavenge ejectors
2 Main ejectors

Question 16

Fuel flow

Answer 16

Center tank -> Transfer ejectors -> Main tanks -> scavenge ejectors -> Collectors tanks -> main ejectors -> engine

Question 17

Transfer ejectors

Answer 17

FSC will open the appropriate transfer valve when the main tank drops to 94% of its capacity
FSC will close transfer valve when tank is full

Question 18

DC electric boost pumps

Answer 18

• 2 of them

- Allow for fuel to flow to the engine when the main ejectors aren’t working. Used during engine start.

Question 19

What happens if both scavenge ejectors fail

Answer 19

Fuel can be gravity fed to the collector tank. No action is required.

Question 20

Can the primary ejectors cross feed fuel

Answer 20

No. There’s a one way valve that prevents this from occurring.

Question 21

Can you manually turn on the boost pump?

Answer 21

No, but you can arm them. The FSC then turns on the boost pump when low fuel pressure is detected from the main ejector on than side. When the FSC turns on one boost pump it always turns on the other boost pump as well.

Question 22

Boost pump switchlight

Answer 22

• INOP illuminates any time the boost pump is not armed (not selected in, flush with the panel). Also illuminates when the boost pump fails
• ON illuminates when when the boost pump is on

Question 23

Emergency fuel shutoff valve (SOV)

Answer 23

• Stops the fuel of fuel to the engine

- Controlled by the EIGINE FIRE PUSH switchlight.

Question 24

Fuel heat exchanger

Answer 24

Cold bulk fuel is heated by the high temperature engine oil passing through the heat exchanger.

Question 25

APU fuel pump

Answer 25

Draws fuel from the left collector tank
Internal bypass valve will allow suction to keep APU running if the pump fails. This Valve will not allow the APU to be started if the pump

Question 26

APU shutoff valve

Answer 26

…

Question 27

How many fuel quantity probes

Answer 27

17 total
6 in each tank
3 in the center tank
1 in each collector tank

Question 28

Magnetic level indicators (MLI’s)

Answer 28

A float type measuring system on the bottom of the wing.

Question 29

Emergency Procedures checklist (EPC’s)

Answer 29

PF: “Cancel, identify.”
PM: Press the caution/warning button and read the associated message
PF: If EPC, “reference the EPC for…”
PM: Runs the correct checklist and says, “EPC complete… refer to the ____ tab for expanded procedure.”
If QRH: “I have the radios and controls, reference the QRH for…”