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Atlas B747 > Fuel System > Flashcards

Fuel System Flashcards

1
Q

Max Total Fuel Qty

A

163.0 kgs

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2
Q

Center Fuel Tank Qty

A

52.2 kgs

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3
Q

Main Tanks 2/3 Qty

A

38.1 kgs

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4
Q

Main Tanks 1/4 Qty

A

13.3 kgs

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5
Q

Reserve Tanks 2/3 Qty

A

4.0 kgs

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6
Q

When main tanks 2 or 3 @ _____ kgs, CWT fuel is scavenged via 4 jet
pumps into Main tanks 2 & 3.

A

27.2 kgs

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7
Q

When main tanks 2 or 3 @ ______ kgs, Reserve x-feed valves open and
fuel is gravity fed to Main 2 & 3.

A

18.2 kgs

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8
Q

During Fuel Jettison, when main tanks 2 or 3 levels reach _____ then
main tanks 1 & 4 transfer valves open and gravity feed into main tanks
2 & 3.

A

9,072 kgs

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9
Q

FUEL LOW CTR L,R
Center wing tank quantity less than _____ kgs before start with pump
switches ON.

A

7,700 kgs

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10
Q

FUEL LOW CTR L,R
Center wing tank quantity approximately _____ kgs in climb with pump
switches ON.

A

3,200 kgs

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11
Q

FUEL LOW CTR L,R
Center wing tank quantity approximately _____ kgs in cruise with pump
switches ON.

A

1,300 kgs

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12
Q

Standpipe level in main Tanks during override and jettison operation.

A

3,200 kgs

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13
Q

“FUEL IMBAL 2-3”
Fuel difference of _____ between main tanks 2 & 3. Message no longer
displayed when difference is less than ___ kgs.

A

2,720 kgs

450 kgs

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14
Q

“FUEL IMBALANCE”
After reaching FUEL TANK/ENG condition, there is a longitudinal fuel
imbalance of _____ kgs between inboard main tanks and outboard main
plus reserve tanks. Message no longer displayed when difference less
than ___ kgs.

A

2,720 kgs

450 kgs

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15
Q

“FUEL IMBAL 1-4”
Fuel difference of _____ kgs between main tanks 1 & 4. Message no longer
displayed when difference less than ___ kgs.

A

1,360 kgs

450 kgs

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16
Q

When CTR quantity drops below _____ kgs and total fuel consumption
is greater than _____ kgs per hour, the CTR override/jettison pumps can
no longer provide full override of the outboard main tank pumps. As
a result, a shared flow situation between the CTR and outboard main
tanks is established. During this shared flow situation, approximately ___
kgs of fuel are consumed from each outboard main tank prior to display
of the EICAS message FUEL LOW CTR.

A

2,300 kgs

6,800 kgs

900 kgs

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17
Q

“Fuel IMBAL EICAS” on primary message no longer displayed when
difference is less than ___ kgs.

A

450 kgs

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18
Q

“FUEL TEMP LOW”

Fuel temp ____ or less. Fuel temp on upper display turns _____. Based on __ above Jet A temp of -40*C.

A

-37* C

Amber

3* C

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19
Q

What happens when you arm the Fuel Jettison Selector Switch?

A

1-Arms Jettison Systems
2- Replaces Fuel to Remain on Upper Display
3-Fuel Synoptic updated with Jettison System
4-Jettison Time displayed on Lower Display

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20
Q

What are FSMCs?

What are there two primary functions?

A

Fuel System Mgt Cards
1- Command Fuel Valves Open or Closed
2-Command Fuel Pumps on or off
(IAW Fuel System Logic)

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21
Q

Minimum Fuel for Takeoff

A

25,000 kgs

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22
Q

During Engine Start what is the status of the fuel pumps and fuel X Feed Valves?
Which tank(s) are supplying fuel to which engines?
(Assuming full fuel load)

A

All fuel pumps - on
All X-Feed Valves - Open

CTR Tank fuels all engines

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23
Q

When flaps are extended to T/O position what is the fuel system configuration? (Tanks - Pumps - Eng)
(Assuming full fuel load)

A

1- X-Feed Valves 2&3 are closed
2- CTR tank supplies fuel to Engines 1&4
3- Main Tank 2 supplies Engine 2 / Main Tank 3 supplies Engine 3

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24
Q

What are the functions of the Override/Jett pumps?

A

Provide increased PX for fuel system requirements and fuel jettison capability.

25
Q

How many AC pumps are in each tank?

A

2x AC pumps in each Main Tank
2x OVRD/Jett Pumps in each Main Tank 2/3
2x OVRD/Jett Pumps in CTR Tank

26
Q

How many scavenge fuel pumps exist in the system?

Where do they move fuel?

A

4x Pumps in CTR Tanks

Transfers fuel from CTR to Main Tanks 2/3

27
Q

Standpipe fuel level is ____ kgs

28
Q

What does the cyan color on a fuel pump denote?

A

Fuel pump is armed but INH

29
Q

What does an amber fuel tank on the fuel synoptic display indicate?

A

A fuel imbalance or <900kgs in the tanks

30
Q

”> FUEL TANK/ENG” (inflight EICAS)

A

X-FEED Valve 1 or 4 open:
Main Tank 2 <= Main Tank 1
or
Main Tank 3 <= Main Tank 4

31
Q

What does a fuel “VALVE” light mean on the OVHD panel?

A

1- Fuel valve is in transit

2- Switch not in the commanded position

32
Q

How many transfer valves are there in the reserve tanks? Why are there ___?

A

2 - to mitigate pump cavitation

33
Q

Main Tank AC pumps can provide fuel to ___ x Engines at T/O thrust and ___x Engines in cruise.

A

1x Engine in T/O thrust

2x Engines in cruise thrust

34
Q

OVRD/Jettison fuel pumps can provide fuel to ___ x Engines at T/O thrust and ___x Engines in cruise.

A

2x Engines in T/O thrust

2x Engines in cruise thrust

35
Q

OVRD/Jettison fuel pumps can operate to a fuel level of ____kgs

A

3.2 kgs (standpipe level)

36
Q

Fuel “PRESS” light indicates _______.

“ON” + “PRESS” light indicates _____.

A

Fuel output pressure is low or pump is “OFF”

Pump is on with Low Pressure

37
Q

1- Which tank normally supplies fuel to the APU?
2- Which pump(s) operate to supply fuel to the APU?
3- How is fuel supplied without power to the aircraft?

A

1- Main Tank 2

2- When AC power available - aft boost pumps in Main Tank 2 & 3 operate. Aft pump Main 2 primary. Aft pump 3 backup and to prevent tank-tank transfer.

3- DC pump in Main Tank 2 supplies fuel to APU (battery start)

38
Q

How does burning fuel from the CTR tank affect CG?

A

CG shifts aft

39
Q

”> FUEL TANK/ENG” (inflight EICAS)

Which switches need to be actuated in which order?

A

1- Pumps off

2- X-FEED valve closed

40
Q

Jettison fuel pressure is provided by which pumps?

A

CTR Pumps

OVRD Pumps in Main 2 & 3

41
Q

What is one situation you may want to jettison fuel?

A

Reduce Gross Weight in an Emergency situation

42
Q

L - NOZZLE - R

Guarded switches on the OVHD panel execute which two functions?

A

1 - Opens Jettison Nozzle Valves

2- Activates OVRD/JETT pumps

43
Q

“FUEL IMBAL 1-4”
What type of imbalance is this?
Advisory occurs when? Goes away when?

A

Fuel difference of 1,360kg between Main tanks 1 & 4

Message goes away when diff < 450kgs

44
Q

“FUEL IMBAL 2-3”
What type of imbalance is this?
Advisory occurs when? Goes away when?

A

Fuel difference of 2,720kg between Main tanks 2 & 3

Message goes away when diff < 450kgs

45
Q

How does a longitudinal fuel imbalance occur?

“FUEL IMBALANCE” EICAS displayed

A

If Tank 2 + 3 does not = 1 + 4 + (R2+R3)

Draw tanks out with a line between 1/2 and 3/4

46
Q

Why do the FSCMs not automatically balance fuel?

A

To avoid masking a fuel leak

47
Q

Which crossfeed valves are affected by flap extension on the ground?

A

FSCMs close X-FEED valves 2 & 3 when flaps extend to T/O position on the ground

48
Q

Which fuel pumps are system logic pumps? In other words, which fuel pumps are commanded to turn on and off by system logic during normal operations?

A

OVRD/Jett pumps 2 and 3

49
Q

Trace the flow of fuel to the engines when there are 7700 kgs or more fuel in the Center Wing Tank from blockout.

A

-Both CWT pump switches should be ON.
-The FSMCs close crossfeed valves 2 and 3 when flaps extend to takeoff position
on the ground. Override/jettison pumps 2 and 3 are inhibited from operating when
pressure is detected from both CWT override/jettison pumps. The CWT
override/jettison pumps provide fuel to engines 1 and 4 and main pumps 2 and 3
provide fuel to their related engine.

50
Q

Trace the flow of fuel to the engines when there is less than 7700 kgs of fuel in the Center Wing Tank from blockout.

A

-Both CWT pump switches should be off.
-The FSMCs close crossfeed valves 2 & 3 when flaps extend to takeoff
position on the ground.
-Override/jettisons pumps 2 provide fuel to engine 1 and
override/jettison pumps 3 provide fuel to engine 4. Main pumps 2 and 3 provide
fuel to their related engine.

51
Q

When do the FSMCs open the reserve transfer valves?

A

Main Tank 2 OR 3 <18.2kgs

52
Q

Can fuel be manually transferred from any tank to another tank?

53
Q

Describe how the fuel quantity indication changes upon termination of fuel jettison.

A

Fuel to remain quantity changes from Magenta to white and flashes for 5 secs

54
Q

Does the suction feed line go through the main tank fuel pumps?

A

No- the suction feed line bypasses the pumps

55
Q

In general, how are fuel imbalance situations handled?

A

Opening or closing X-FEED valves and turning off/on fuel pump switches.

56
Q

Fuel temperature is measured in which tank?

A

Main Tank 1

57
Q

What three different conditions will generate a fuel imbalance message on the EICAS?

A

1- Fuel difference of 1,360kg between Main tanks 1 & 4

2-Fuel difference of 2,720kg between Main tanks 2 & 3

3-A fuel imbalance or <900kgs in the tanks

58
Q

When does the fuel imbalance message no longer display on the EICAS?

A

<450kgs of imbalance

59
Q

When are Override/Jettison Pumps 2 and 3 displayed in Cyan on the Fuel System Synoptic?

A

Armed for system logic operation

Atlas B747 (31 decks)

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