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Boeing 757 Technical > Fuel > Flashcards

Flashcards in Fuel Deck (15):
1

When does FUEL CONFIG light come on? (3)

1. Low fuel quantity (less than 1000kg in main tank)
2. Imbalance between left and right main tanks (800kg)
3. Centre fuel tank pumps off with fuel in centre tanks (more than 600kg)

2

Each fuel tank contains how many AC fuel pumps?

2

3

Which fuel tank pumps have the higher pressure and why?

Centre tanks have higher pressure than main tanks so centre tank fuel gets used first.

4

What does PRESS light mean for fuel pumps?

Low output pressure

5

With the centre pump switches off are their low PRESS lights and EICAS messages displayed?

No, they are inhibited

6

When does electrical load shedding occur for the centre fuel pumps?

Below 50% N3

7

What does L or R FUEL SYS PRESS mean?

When all fuel pumps on one side have low output pressure and crossfeed valve switches are off

8

Describe the centre tank scavenge system?

When left main tank gets below 50% the centre fuel tank is scavenged for fuel and put into the left main tank

9

Describe the automatic centre tank fuel pump removal system?

Turns the centre pumps off several seconds after the respective display of CTR FUEL PUMP

10

What additional pump does the left main tank have?

A separate DC pump for the APU for when main AC power is not available (i.e. APU starting without ground power)

11

What isolates the two main L and R fuel crossfeed manifolds?

Two crossfeed valves

12

What does the fuel crossfeed switch VALVE light mean?

Disagreement between valve and switch position

13

Can engines suction feed and what is a small risk of occurring?

Yes they can and sometimes air in the suction feed line can cause fuel flow reduction with risk of flameout or thrust deterioration at high altitude

14

Tank quantities? (kg)
Total?

1. Mains = 6594kg each
2. Centre = 21082kg
3. Total = 34270kg

15

Number of fuel tanks (names)?

3, left centre, main