Skyblue CBT fuel system

Question 1

what can each wing tank carry?

Answer 1

2500kg of fuel

Question 2

how much does the feeder tank carry?

Answer 2

160kg

Question 3

what is the feeder tank used for?

Answer 3

ensures that fuel is available for pumping through all flight manouvres

Question 4

what does the feeder tank use to pump fuel?

Answer 4

an electric pump and a jet pump

Question 5

what is max fuel imbalance between tanks?

Answer 5

730kg

Question 6

what are the 2 fuel lines that cross the wing center box used for?

Answer 6

1 for crossfeed and the other for refueling the left tank

Question 7

what does the vent line do?

Answer 7

prevents concentration of fuel vapour

Question 8

what does the ven system do?

Answer 8

keeps a positive pressure on the fuel in the tanks while the aircraft is pitching and rolling

Question 9

where are the surge tanks?

Answer 9

outboard section of the wings. fuel is vented to these tanks

Question 10

what does the NACA vent?

Answer 10

provides atmospheric pressure to the surge tank and prevents ice accumulation on the surge tank inlet

Question 11

what does the float valve do?

Answer 11

allows fuel to collect into the surge tank before it is returned to the fuel tank via the vent duct

Question 12

how is excess fuel drained in the event of overfuel?

Answer 12

through the surge tank inlet into the surge tank

Question 13

how long does it take to completely refuel the aircraft?

Answer 13

16 mins

Question 14

what is max pressure for fueling?

Answer 14

50 psi

Question 15

what can we not do when refueling?

Answer 15

• operate switches
• smoke
• use a phone
• refuel near a thunderstorm

Question 16

what controls flow of fuel during refueling to each wing tank?

Answer 16

2 solenoid refuel control valves downstream of the refuel connector

Question 17

what happens when the refuel valves are opened?

Answer 17

fuel flows to the associated tank and dispensed through diffusers

Question 18

what normally closes the refueling valves?

Answer 18

fuel quantity indicating system in the FCU closes the valves when the tank reaches 2500kg

Question 19

what is the purpose of the backup high level sensor in each tank?

Answer 19

control the refuel valve in the event of a malfunction of the Fuel indicating systems high level sensor

Question 20

how is defueling carried out?

Answer 20

by applying 11 psi suction to the connector and opening the refueling valves

Question 21

how many litres will the feeder tank hold?

Answer 21

200L

Question 22

what is the purpose of the electrical pump?

Answer 22

supplies fuel to one engine throughout the whole flight envelope

Question 23

what powers the electric fuel pump?

Answer 23

DC ESS BUS

Question 24

What can the electric fuel pump and its associated jet pump do?

Answer 24

can supply both engines throughout the entire flight envelope

Question 25

when can one jet pump not supply both engines?

Answer 25

when using jet b fuel

Question 26

when is the electric fuel pump mainly used?

Answer 26

for engine start. it shuts down once the engine is operating

Question 27

what 2 directions does the elctrical fuel pump send fuel?

Answer 27

1. through a check valve and out to the LP fuel valve
2. through a check valve to a feeder jet pump in order to refuel the feeder tank

Question 28

when is the LP fuel valve closed?

Answer 28

when the fire handle is pulled

Question 29

what is required to close the LP valve?

Answer 29

electrical power from the HOT EMER BAT BUS or the associated DC BUS

Question 30

where does fuel flow after the LP valve? (in order)

Answer 30

1. fuel heater
2. HP pump
3. fuel filter
4. hydro mechanical unit (HMU)
5. engine

Question 31

where does the HMU send fuel?

Answer 31

1. engine
2. to the motive flow valve to provide pressurised fuel to operate the jet pump

Question 32

what controls the motive flow valve?

Answer 32

button on LH overhead panel

Question 33

how is fuel pumped back to the feeder tank?

Answer 33

tapped off the engine jet pump and fed through a check valve to the feeder jet pump

Question 34

what does the pressure sensor monitor?

Answer 34

output of each feeder jet pump

Question 35

what if fuel pressure drops below 5psi?

Answer 35

electric jet pump starts automatically as long as the button is pushed in

Question 36

what does FEED LO PR mean?

Answer 36

fuel pressure below 4 psi

Question 37

what will both electrical pumps do during crossfeed operations?

Answer 37

automatically start as long as the buttons are pushed in

Question 38

at what feeder tank level will the electric fuel pump begin to operate?

Answer 38

below 160kg. this is accompanied by FUEL LO LVL on EWD

Question 39

what powers the fuel crossfeed valve?

Answer 39

DC ESS BUS

Question 40

how many fuel probes are there per tank?

Answer 40

6

Question 41

what does the fuel quantity system operate based on?

Answer 41

dielectric constant of fuel and fuel density

Question 42

what is used to measure fuel quantity on the ground in the event of an indiczting system failure?

Answer 42

magnetic fuel indicator which measures amount in cm

Question 43

what do the pump push buttons control?

Answer 43

electric fuel pump and motive fuel valve

Question 44

when will the motive fuel valve close?

Answer 44

when sufficient fuel pressure is unavailable

Question 45

when will the electric fuel pump automatically switch off?

Answer 45

when jet pump pressure exceeds 8.5psi for 30 seconds

Question 46

what does 2 amber dashes on the fuel temp readout mean?

Answer 46

invalid data

Question 47

what does an amber LP valve indication mean?

Answer 47

LP not open or closed after 3 seconds

Question 48

what does a CLOG caution mean?

Answer 48

excessive pressure loss at the fuel filter

Question 49

how many magnetic level indicators are there in each tank?

Answer 49

2