Fuel System

Question 1

MAX FUEL TEMP? Where is it taken from?

Answer 1

49C

L MAIN TANK for most accurate reading as it only has one heat exchanger.

Question 2

Any excess fuel is sent?

Answer 2

Surge Tanks which will return to C TANK via gravity

Question 3

A blank fuel level indication indicates?

Answer 3

• NO POWER
• SYSTEM FAILURE

Question 4

FUEL QTY INDICATORS values?

Answer 4

Measured by probes, corrected for density then displayed on indicator for each tank.

Question 5

TOTAL FUEL QTY Indication?

Answer 5

• Separate calculation from tank indicators
• Provided to the FMC as “TOTALIZER”
  
  • values should always match

Question 6

C FUEL PUMPS inhibited?

Answer 6

When associated engine below 50% N2

_{<em>this is done to reduce electrical loads</em>}

Question 7

Exception to C FUEL PUMPS inhibition?

Answer 7

• Fueling door open.
  
  • Allows fuel to be pumped out of C TANK.
• Fuel Jettison
  
  • Allows jettison of all C TANK FUEL

Question 8

Do C FUEL PUMPS shut OFF automatically under normal flight conditions when fuel level reaches 1200lbs?

When is leftover C FUEL scavenged?

Answer 8

YES, they automatically shut off.

Fuel is scavenged to L MAIN* when it’s half full.

^{<em>*according to CPAT, book says it goes to both</em>}

Question 9

3 conditions for FUEL CONFIG light + EICAS MSG?

Answer 9

1. L/R MAIN TANK QTY differs by 2000 (+/-500)
2. C FUEL PUMP Switches are OFF w/ more than 1,200lbs in C TANK
3. LOW FUEL (MAIN TANK below 2200lbs)

Question 10

Will dedicated AC PUMP (L FWD) provide pressure to APU with AC PWR established even if switch is OFF?

Answer 10

YES, PRESS light will extinguish regardless of switch position.

Question 11

FUEL JETTISON rate and time to empty?

Answer 11

2,600lbs per minute

30 mins to empty full C TANK

Question 12

JETTISON inhibits (3)?

Answer 12

• FMC Calculated Fuel
  
  • So we don’t get leak message.
  • Resets to totalizer value after JETTISON complete
• C FUEL PUMPS Power Removal
  
  • so we can JETTISON all C TANK FUEL without them turning off at 1200lbs
• S WINDOW HEAT

Question 13

Is it possible to jettison all C FUEL and still be over MGLW?

Answer 13

YES

Question 14

L/R JET XFER VALVE EICAS?

Answer 14

Position of jettison XFER VLV disagrees with switch position on overhead.

^{<em>*C TANK VLV(s) that opens when we turn JETTISON switch to ON. See image below….</em>}

Question 15

JET NOZ EICAS + VALVE light?

Answer 15

Nozzle valve not in commanded position

Question 16

L/R FUEL JET PUMP EICAS + FAULT light?

Answer 16

Associated fuel jettison pump is INOP

Question 17

Is JETTISON still available with a FAULT indication?

Answer 17

Possibly, depending on FAULT. May be reduced rate.

Question 18

DEFUELING PUMPS provided by?

Answer 18

L/R MAIN or truck suction for MAINS.

C TANK must use its pumps as truck suction not avail.