- 4 x main tanks (1,2,3,4) - center wing tank - 2 x reserve tanks (2,3) - surge tanks in outer portion of each wing - horizontal stab tank with surge tank in outboard portion (pax)

- 8 x AC powered main tank pumps (2 per main tank) - 4 x AC powered override/jettison pumps (2 each for main tank 2 and 3) - 2 x Center Wing Tank (CWT) pumps (override/jettison)

- 4 scavenge pumps in CWT - ensure all fuel from CWT to Main Tanks 2 and 3 - no control or indications - begins when main tank 2 or 3 decrease to approx 27,200 kgs

Fuel Flashcards by Christopher Kociban

EICAS color indications of fuel pump status

White - pump off
Green - pump on
Amber - pump low pressure

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How many fuel tanks?

4 x main tanks (1,2,3,4)
center wing tank
2 x reserve tanks (2,3)
surge tanks in outer portion of each wing
horizontal stab tank with surge tank in outboard portion (pax)

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How many fuel pumps?

8 x AC powered main tank pumps (2 per main tank)
4 x AC powered override/jettison pumps (2 each for main tank 2 and 3)
2 x Center Wing Tank (CWT) pumps (override/jettison)

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Main and Override pump pressure capability

Main Pumps
- each pump can provide enough fuel for 1 engine during TO or 2 engines during cruise

Override/Jettison Pumps

each pump can provide enough fuel for 2 engine during TO and cruise
higher output than main pumps
center wing pumps are Override/Jettison pumps
horizontal stab tank pumps are override/jettison pumps (Pax)

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Fuel Tank Capacities

Main 1 and 4: 26,576 kg (13.3 ea)
Main 2 and 3: 76,263 kg (38.1 ea)
Center: 52,167 kg
Reserves: 8,036 kg (4.0 ea)
Stab Tank (pax): 10,030 kg

Total (freight): 163,042 kg
Total (pax): 173,072 kg

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When does fuel transfer from Reserve Tanks to Main tanks 2 or 3?

each reserve tank has two transfer valves
via gravity fuel transfers when main tank 2 or 3 drop below 18,200 kg
transfer valves can be open manually (RSV 2 and 3 XFER) or automatically by system logic

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Which tank is normal/backup source for APU fuel?

Main tank 2 supplied by main pump 2 aft
Bankup is Main pump 3 aft
DC pump in main tank 2 for APU battery start

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How is fuel system logic managed?

2 x Fuel System Management Cards (FSMCs) command fuel valves and pumps open or closed

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How is fuel jettisoned from the tanks?

Fuel Jettison selector rotated out of OFF position
Jettison Nozzle Valve On
Override/Jettison pumps (Main 2 and 3, CWT) pump fuel from all fuel tanks overboard

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What causes a FUEL IMBALANCE EICAS message?

imbalance between Main 1 and 4 of 1,360 kg
imbalance between Main 2 and 3 of 2,720 kg
message is removed when difference less than 450 kg

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How is Fuel Quantity and Fuel Temperature measured?

Fuel Quantity sensor in each tank

- Fuel Temp sensors in main tank 1

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How is fuel flow displayed in the Fuel Synoptic page

Fuel flow is simulated based upon the pump status and valve positions
may no represent actual system operation

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How is fuel management controlled?

2 x Fuel System Management Cards (FSMCs)

fuel valves open or closed based on logic
fuel pumps ON or OFF based on logic

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Which fuel pumps are on with the APU Running prior to engine start?

Main tanks 2 and 3 (PRESS light will be off)

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How many surge tanks per wing?

one surge tank per wing
provide fuel surge relief and tank venting
no controls or indications to flight crew

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How many Fuel Crossfeed Valves

4 x Fuel Crossfeed Valves in fuel manifold

- fuel can be delivered from any Main Tank or CWT to any engine or APU

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Where is the Defuel Panel located?

overhead maintenance panel

- not normally used by flight crew

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Scavenge System

4 scavenge pumps in CWT
ensure all fuel from CWT to Main Tanks 2 and 3
no control or indications
begins when main tank 2 or 3 decrease to approx 27,200 kgs

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How is Fuel Balanced between tanks?

opening and closing of Crossfeed valves

- turning ON or OFF of specific pumps

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Where is Fuel system information displayed?

Primary EICAS

- FUEL synoptic page

Color indications for pumps on FUEL synoptic page?

White - OFF
Green - ON
Amber - Low Press
Cyan - Armed for System logic (override pumps)

What would cause Fuel Main tank quantity to display in Amber?

imbalance condition

- less than 900 kg (2000 lbs)

Fuel Density of usable fuel at level attitude

0.8 kgs per liter

How much capacity can each AC Main pump support?

one engine at Takeoff Thrust; or

- two engines at cruise thrust

How much capacity can each override/jettison support?

- two engines at takeoff or cruise thrust

What fuel quantity can override/jettison pumps 2 and 3 operate until?

Until standpipe level of approx 3,200 kg (7,000 lbs) * avoids jettison of all fuel

Which pumps have priority over all others?

CWT override/jettison pumps override all other pumps * OJPs 2 and 3 are inhibited * One CWT pump will not inhibit or override

Can engine receive fuel if fuel pump pressure is low?

- Suction feed line to each engine, which bypasses fuel pumps - at hight altitudes reduced thrust or engine flameout may occur (dissolved air restricting fuel flow)

How is each fuel pump activate?

Main pumps - manually via Main pump switch ON | Override/jettison pumps - system logic with switch ON

When does fuel transfer from Main tanks 1 and 4 to Main tanks 2 and 3?

- one transfer valve in each of Main tank 1 and 4 - not a normal operation - Manually via FUEL XFER MAIN 1 and 4 - automatically during fuel jettison when 2 and 3 tanks drop below 9,072 kg - fuel transfers via gravity - transfers to approx 3,200 kg in each outboard main tank

When should the CWT pump switches be ON during normal flight ops?

When CWT has 7,700 kgs or more of fuel

>FUEL TANK/ENG EICAS message

- Fuel in main tank 2 is equal or less than main tank 1 - Fuel in main tank 3 is equal or less than main tank 4 Actions: 1) Manually turn #2 and #3 OVRD pumps OFF 2) Manually CLOSE cross feeds #1 and #4

Which pumps provide jettison fuel pressure?

- override/jettison pump 2 and 3 and CWT OJPs

When is Fuel Jettison prohibited?

With flaps in TRANSIT between 1 and 5

How many jettison control systems?

2 (A or B)

What kind of fuel supply?

Tank to engine

When does fuel temperature indication turn amber?

-37º C and below

Which tanks is fuel jettisoned from?

All tanks via Main tanks 2 and 3 and CWT

What EICAS indication do you get when FUEL JETTISON selector is out of OFF (A or B)

Fuel to remain (TO REMAIN) replaces fuel temp

With fuel tanks full what pumps are supplying engine during start?

Both Center Wing OJPs

Fuel Pump/Cross-feed valve configuration with Flaps Set for Takeoff (Center tank over 7,700 kg of fuel)

CWT pumps ——> Engines 1 and 4 Main pumps 2 ——> Engine 2 Main pump 3 ——> Engine 3 Cross-feed valves 2 and 3 ——>closed

Fuel Pump/Cross-feed valve configuration with Flaps Set for Takeoff (Center tank less than 7,700 kg of fuel)

``` Override/jettison pump 2 ——> engine 1 Override/jettison pump 3 ——> engine 4 Main pump 2 ——> engine 2 Main pump 3 ——> engine 3 Cross-feed valves 2 and 3 ——> closed ```

Fuel Pump/Cross-feed valve configuration with Flaps Up after Takeoff (Center Tank On)

CWT Override/Jettison pumps ——> all engines | All cross-feed valves ——> open

Fuel Pump/Cross-feed valve configuration with Flaps Up after Takeoff (Center tank pumps off)

Override/jettison pumps 2 ——> ENG 1 and 2 Override/jettison pumps 3 ——> ENG 3 and 4 Cross-feed valves 2 and 3 ——> Open

FUEL LOW CTR L, R EICAS Message

- CWT less than 7,700 kgs before start with pump ON - CWT approx 3,200 kg in climb with pump ON - CWT approx 1,300 kg in cruise with pump ON

What happens to the fuel quantity indication upon termination of fuel jettison?

- fuel to remain changes colors from magenta to white and flashes for 5 secs

What is the impact of an excessive fuel imbalance on the aircraft?

Adversely affects: - CG - aerodynamic drag - fuel economy

When is an engine on suction feed, and how are suction feed situation corrected?

- suction feed begins when main tank pressure is low | - corrected by opening appropriate cross-feed valves to obtain pressure from a main tank with operations pumps