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A388 CBT EK Pre-Join > CBT - Fuel > Flashcards

CBT - Fuel Flashcards

1
Q

What does a fault light indicate on any of the Main and Stby Feed Tank pumps?

A

Faulty pump or low fuel pressure.

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2
Q

What does this inication mean on the X-Feed pump?

A

The cross feed valve is open without being selected On

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3
Q

Describe the main and secondary roles of the Fuel system

A
  • Stores, monitors and XFR fuel.
  • Supplies fuel APU and Engines
  • Maintain CG limits
  • Alleviate Structural Loads
  • Contol re/defuel
  • Enable Fuel Jettison
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4
Q

What computer controls, monitors and relays fuel system data?

A

2 FQMS Fuel Quantity and Management Systems

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5
Q

What are the funtions of the Fuel Quantity and Management Systems

A
  • Fuel Quantity and Temp Measurement
  • XFR and Jettison Control
  • Refuel Defuel Control
  • Fault Detection and reporting
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6
Q

Where is fuel stored and how many tanks are there

A

5 on each Wing and one trim tank (TRIM TK) on THS. 11 tanks total
Each wing has:
* 1 Outer Tank (OUTR TK)
* One Mid tank (MID TK)
* One Inner tank (INR TK)
* 2 feed tanks (FEED TK)

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7
Q

What is the role of FEED tanks?

A

They are used to feed engines and APU.

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8
Q

What is the role of the OUTR MID INR and TRIM Tanks?

A

They are called Transfer Tanks. They are used for fuel and load alleviation transfers.

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9
Q

Other than store and xfr tanks, what tanks exist in the fuel system?

A

Each wing has one surge and one vent tank. THS has a vent/surge tank. They are not displayed on FUEL SD

Surge tanks collect fuel that may overflow from any fuel tank during operation.
Vent tanks allow each fuel tank to be ventilated to the atmosphere

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10
Q

Where does the fuel that flows into the surge tank go?

A

Goes back into the outboard FEED TKs on wings and TRIM TK on THS

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11
Q

What is the total useable fuel quantity on the A380?

A

254 T

Base on SG 0.785

so in UAE 0.76 - 0.77 will allow 246-249 T Max

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12
Q

What are the main independent systems that are subsets to the fuel system?

A
  • Fuel Transfer System
  • Engine and APU Fuel Feed System
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13
Q

What are the components and capacity of the FEED Tks?

A

Each feed tank incorporates a collection cell that houses 2 fuel pumps. One main pump and a stby pump.

Capacity of the collection is 1500 on FEED TK 1 & 4
Capacity of the collection is 1300 on FEED TK 2 & 3

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14
Q

What is the purpose of having a collector cell in the FEED TKs?

A

The collector cell is kept full to prevent fuel pump cavitation by keeping the fuel pumps submerged.

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15
Q

How many fuel pumps feed the engines?

What is the minimum required to feed all engines using the X-FEED

A

4 Main and 4 STBY pumps. The onside STBY pump automatically takes over in case the main one is off or becomes faulty

2 Pumps are sufficient to feed all engines using X-FEED

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16
Q

How many X-FEED valves are there and what are their purpose?

A

Four, one on each engine feed pipe. They allow any main or stby pump to supply any engine. They can also be used to manually correct an imbalance between FEED TKs

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17
Q

What redundancy is built to allow engines to be supplied with fuel in case of total engine feed pump failures? What is its limitation

A

Engines can be fed by gravity via non return valves at the bottom the collector cell. FEED TKs 1 anf 4 will operate normally but FEED TKs 2 and 3 will each have 2000kg of unusable fuel

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18
Q

Similar to the ENG FEED TKs, can the OUTR/MID/INR TKs XFR by gravity?

A

Only the OUTR can XFR by gravity. In case of dual pump fail on associated MID/INR/TRIM TKs then their fuel is unusable.

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19
Q

What doe the ENG Master sw control?

A

Its associated LP Valve (Low pressure Valve)

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20
Q

How is the APU normally fed?

A

It is supplied by the main in FEED TK 4. It can also be fed by all other main or stby pumps using X-feed, and also via its associated APU Feed Pump

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21
Q

When does the APU Feed pump take over from the FEED TK 4 main pump?

A

The ENG 4 pumps are not running, or
The fuel pressure is too low for the APU to operate correctly.

It is not displayed on the SD

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22
Q

What tanks are associated with the transfer system?

A

All excpet the FEED/VENT/Surge TKs.

So basically INR MID OUTR TRIM

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23
Q

What is the main function of the fuel transfer system?

A

Load Alleviation
XFR into the FEED TKs
CG XFRs
Cold FUEL XFRs

Other funtions include the Refuel/Defuel on ground Jettison in flight

24
Q

What are the subsets of the fuel transfer system?

A

It has two independent galleries.
The FWD and AFT gallery

Auto imbalance of fuel is managed by the FQMS

25
Q

How is the TRIM TK connected to the Fuel XFR system?

A

Trim pipes connect the TRIM TK to the AFT and FWD galleries.

26
Q

What are the pumps associated with the transfer system on the INR MID OUTR TRIM tanks?

A

Transfer pumps (XFR PMPs)

12 total, 2 on each the MID INR TRIM and one on each OUTR

27
Q

In addtion to transfer pumps (XFR PMPs) what is incorporated in the fuel transfer system to aid in its funtion?

A

Each wing tank has two inlet valves, one for each gallery. The TRIM TK has 2 inlet valves that can connect to both or either galleries.

In the MID INR and TRIM. The inlet valves can also act as outlet valves as shown in the image

28
Q

What redundancies are added in case of emergencies in the fuel xfr system?

A

In each wing, an emergency outer tank transfer valve connects the OUTR TK to the outer FEED TK (FEED TK 1 and 4).

29
Q

Trim tank isolation and inlet valves allow fuel to be transferred:

A

AFT on ground, and
FWD on ground and in flight.

30
Q

In normal ops, how are the FWD and AFT Galleries used?

A
  • FWD Gallery: Main XFR from OUTR MID INR to FEED TKs, or for load alleviation XFR to and from the OUTR TKs
  • AFT Gallery: Along with the Trim Pipe are used for CG and main XFR from the TRIM TK to INR TK.

Both galleries operate independently and simultaneously

31
Q

In case of failure in one of the galleries:

A

the other gallery automatically takes over for alternate fuel transfers.

32
Q

When do the FWD and AFT galleries get interconnected?

A
  • Refuel/Defuel
  • Jettisom
  • Workaround (alternate transfer)
33
Q

What gallery and components are responsible to carry out fuel jettison?

A

Two jettison valves connected to the AFT gallery allow fuel to be jettisoned overboard.

34
Q

In what order is fuel jettisoned?

A

Fuel is jettisoned from all XFR tanks simultaneosly. Feed TKs cannot be jettisoned

35
Q

What is the difference between the “FU TOTAL” vs “FU ALL ENG”

A

FU TOTAL is all ENG and APU
FU ALL ENG is only ENG Burn

36
Q

What fuel distribution is adopted by the FQMS to reduce wing bending moments on ground and in flight?

When do they occur

A
  • Ground: The FQMS will limit the Outer Tank to 50% capacity unless the volume is needed for the scheduled flight and all other tanks are full. (reduce downward bending moment)
  • Flight: The outer tanks are filled to max capacity by INR TKs and kept there as long as possible (reduce upwards bending moment)
  • Before Landing: Same as ground with outer fuel tk and empties the trim tank.

Transfer is automatically paused when reaching FWD CG limit.

The diagram shows load alleviation after takeoff
Before landing TRIM TK XFR occurs if ETA is after 78 min or altitude was above FL 255 and you go below FL 245 and for OUTR to INR it happens at ETA < 28 min

37
Q

What is cold fuel transfer?

A

In cold weather conditions, fuel temperature in the outer tanks may decrease faster than in the other tanks.

To avoid fuel freeze, a Cold Fuel Transfer is automatically done from the outer tanks to the feeding tanks. Then when FEED are FULL, XFR to MID then INR.

Function is lost during alternate xfr

1) When temperature of fuel in any outer tank is < -35ºC, and
2) When any feed tank is < 18 T

38
Q

Which tank usually supplies the FEED TKs and when does it normally operate?

A

The INR tank. It XFRs to the FEED TK when they drop below a threshold and threshold + 1 Ton.

Threshold is around 20-21 Tons reducing to 18-19 when 90 min from DEST

39
Q

What is the sequence of the main fuel xfr?

A
  • INR to FEED
  • MID to FEED
  • TRIM to FEED
  • OUTR to FEED
40
Q

What does the OUTR/MID/INR TK XFR pb sw control?

A

manual transfer from OUTR/MID/INR TKs to FEED TKs.

Diagram shows the action of the OUTR XFR pb sw

41
Q

What does the TRIM TK XFR pb sw do?

A

Controls the manual transfer from TRIM TK to INR TKs.

42
Q

TRIM TK FEED selector controls the:

A

Trim tank isolation valve.

43
Q

The EMER OUTR TK XFR pb sw activates:

A

it Activates different types of gravity transfer from the OUTR TKs to the FEED TKs. Below are some examples:

1) In case of rotor burst EEC to recover outer tanks fuel by gravity, if both galleries have been broken.
Fuel is transferred from the OUTR TKs to FEED TKs 1 and 4 via the emergency outer tank transfer valves.

2) In case of EEC Fuel is transferred from the OUTR TKs to FEED TKs 1, 2, 3 and 4 via the AFT gallery and the emergency outer tank transfer valves.

expect feed tanks imbalance.

EEC Diagram

So depending on the failure it will use the emergency outer tank transfer valves only, or
The emergency outer tank transfer valves and one or both galleries via inlet/outlet valves.

44
Q

What will happen if crew press OUTR TK XFR with the onside OUTR TK PMP off?

A

EMER OUTR TK XFR valve will open

45
Q

What default target CG will the FQMS target during refueling?

A

39.5 %

If ZFW CG is not insterted, before refueling it is defaulted to 36% 300T

46
Q

What is the function of the AUTO GND XFR pb sw?

A

In case of ZFW change after refueling, the AUTO GND XFR pb sw enables to redistribute the fuel, in order to obtain the ground CG target.

47
Q

Incase of a single transfer pump failure, what will the FQMS automatically do?

assuming FWD MID XFR Pump fail

A

It will turn off the symmetrical pump on the other wing as to prevent an imbalance and automatically initiates an alternate XFR via the aft gallery. So the AFT gallery now does main XFR and load alleviation XFR to/from OUTR TKs.

Diagram showing fault. Notice how when a GC XFR is required it is done via the TRIM TK simultaneously via the FWG Gallery (also TRIM load alleviation)

Other XFRS remain unaffected

48
Q

From the XFR tanks, can they XFR via gravity in case of total pump fail?

A

Only the OUTR TKs and in some conditions the TRIM TKs have this perk.
OUTR TKS can gravity supply the
FWD Gallery Feeds 1 & 4
AFT Gallery Feeds 2 & 3

Emergency Outer Tank Transfer valves open to increase transfer rate

The TRIM TANK can be gravity fed if ATT < 3º and not all is usable

49
Q

In case with a single pump failure in either MID/INR tank and the AFT gallery taking over to FEED, what happens if one of the inlet valves that took over also starts failing?

A

FQMS commands and Alternate transfer via the FWD and AFT Galleries

FUEL ALTN XFR is displayed as a memo

50
Q

What does a fault light indicate on any of the FWD(AFT) INR(MID) XFR PMP and OUTR TK PMPs?

A
  • Pump faulty
  • Abnormally ON
  • FU+FOB / BLOCK Disagree Failure
51
Q

What does the indication of FWD and FAULT light mean on the TRIM TK XFR pb

A
  • FWD: Manually XFR from TRIM TKs to INR TKs
  • FAULT: Excessive CG / Low Level in FEED TK / Overflow detected
52
Q

What does the INR(MID)(OUTR) TK XFR pb faut light indicate?

A
  • Automatic transfer no loger possible
  • Low level in a feed tank
53
Q

What do these amber boxes mean for the fuel tank quantity?

A

Half Box: Some fuel unusable
Full Box: Entire Fuel unusable

54
Q

What does the amber underline mean?

A

Fuel imbalance

55
Q

Explain what do these mean

A

A388 CBT EK Pre-Join (20 decks)

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