Fuel

Question 1

How is fueling and defueling accomplished?

Answer 1

Single-point fueling station on right wing

Also used for ground fuel transfer

No provisions for over-wing fueling

Question 2

What is the purpose of the surge tanks?

Answer 2

Collect overflow due to expansion and pressure surges

Capacity is ~235lbs/35gal

Question 3

What is the purpose of the Fuel Crossfeed Valve

Answer 3

Allow any fuel tank to supply any engine

DC motor powered from Battery Bus

Question 4

With all fuel pumps operating which tank is burned first? Why?

Answer 4

Center tank fuel

Center tank fuel pumps have a higher output pressure than main tank fuel pumps

Question 5

Can the APU suction feed fuel?

Answer 5

Yes, fuel is suction fed from the left main wing tank

If fuel pumps are operating, fuel is supplied from left fuel manifold

Question 6

What causes the center tank fuel scavenge jet pumps to operate?

Answer 6

Left (#1) wing tank < 4,500lbs

Scavenges center fuel to left main wing tank

~220 to 450 lbs/hr

Question 7

What is the light logic of the Crossfeed VALVE OPEN light?

Answer 7

Dim blue – valve open with switch open
Bright blue – in-transit or disagreement
Extinguished – valve closed with switch closed

Question 8

What causes an IMBAL (amber) alert? Where is it displayed?

Answer 8

Main tank quantities differ by > 1,000lbs (>60sec)

Extinguishes when imbal < 200lbs

Displayed by fuel quantity indicator

Question 9

What causes a CONFIG (amber) alert? Where is it displayed?

Answer 9

Center fuel > 1,600lbs, and
Center fuel pumps OFF, and
Either engine operating

Displayed by fuel quantity indicator

Question 10

What causes a fuel LOW (amber) alert? Where is it displayed?

Answer 10

Respective main fuel tank < 2,000lbs (>30sec)

Displayed by fuel quantity indicator

Question 11

What does the Nitrogen Generation System do? Where is the status indicator located?

Answer 11

Converts bleed air to nitrogen-enriched air for the center fuel tank

Reduces possibility of fuel vapor igniton

Located in right main wheel well by APU fire control panel

Question 12

With the loss of AC powered fuel pumps, how is fuel provided to the engines?

Answer 12

Each engine can suction feed from its’ respect main tank

Note: while suction feeding at high altitude thrust reduction or flameout can occur

Question 13

What is the logic of the center tank fuel pumps?

Answer 13

Respective CTR FUEL PUMP LOW PRESSURE illuminates, then

After 10 (continuous) seconds, MASTER CAUTION/FUEL

After 15 (continuous) seconds pump shuts off

Question 14

If a fuel quantity indicator fails, how is fuel quantity determined?

Answer 14

Fuel measuring sticks and inclinometers

Question 15

What does the Engine Start Lever control?

Answer 15

Engine Fuel Valve,

Spar Fuel Valve,

Energizes ignition via EEC

Question 16

What do the ENG / SPAR VALVE CLOSED lights indicate?

Answer 16

Dim blue – valve closed
Bright blue – in-transit/disagree
Extinguished – valve open