FUEL SYSTEM

Question 1

How is main and aux fuel tank venting achieved?

Answer 1

Through NACA vents on the surge bay which is connected to the main tank via a standpipe.

Question 2

What happens to any fuel that gets into the vent system?

Answer 2

This gets forced by positive pressure in the surge bay back into the main tanks.

Question 3

Where is fuel tank temperature measured?

Answer 3

Left collector bay, powered by the left secondary bus.

Question 4

Where in the fuel tank system is fuel normally picked up for feed to the engines and how is this done?

Answer 4

From the collector bays via ejector pumps. If an ejector pump fails the AC boost pump can be used.

Question 5

What does the fuel scavenge system achieve? Where does motive flow fuel required for the scavenge system come from?

Answer 5

The scavenge system ensures enough fuel to the collector bay, motive flow for the ejector pumps is suppled by excess fuel from the HMU @>40%Nh.

Question 6

What is the purpose of the AUX PUMPS?

Answer 6

The aux pumps are used to supply fuel in the event of motive flow failure and also supply motive flow for fuel transfer.

Question 7

Under what conditions will aux pump (s) be on?

Answer 7

Take-off and landing

Question 8

What does an ENGINE FUEL PRESS caution light tell you?

Answer 8

The fuel pressure at the engine pump inlet is less than 5.5PSI

Question 9

If a TANK FUEL LOW light illuminates, what is it telling you?

Answer 9

The useable fuel in the respective tank is less than 130lb

Question 10

How does an ejector pump work?

Answer 10

Low volume of high velocity fluid through a venturi which picks up low velocity fluid at high volume.

Question 11

The Dash 8 has 2 main tank fuel gauges in the cockpit as well as 2 main tank fuel gauges on the re-fuelling panel. Which are the master set of gauges and which are the repeaters?

Answer 11

The cockpit are the master indicators.

Question 12

How does the fuel heating system work?

Answer 12

There is a fuel/oil eat exchanger prior to the engine driven pump after the L.P. filter.

Question 13

Is it possible for unfiltered fuel to enter an engine?

Answer 13

yes, if the H.P. filter blocks then fuel will bypass it.

Question 14

What happens to the cockpit fuel gauge pointers when the QTY TEST push button is pressed? What happens if electrical power to a cockpit fuel gauge is lost?

Answer 14

QTY will increase toward full until switch released. no power, needle will drop off scale.

Question 15

What happens if electrical power fails during refuelling?

Answer 15

Refuelling will cease. Fuel valves require power to open.

Question 16

How do you know if the refuel / defuel access panel door has been left open?

Answer 16

Only visually.

Question 17

Maximum main tank fuel imbalance is?

Answer 17

600lb

Question 18

The main tank QTY is?

Answer 18

5678lb (2839 each)

Question 19

How many magna sticks are fitted to each main tank / aux tank? What units do the magna sticks display?

Answer 19

2 per main tank and one per aux. read in USG or litres.

Question 20

How is fuel quantity measured before being displayed on the aircraft gauges? What system triggers the TANK FUEL LOW caution light?

Answer 20

6 capacitance type probes in each tank. The fuel low caution light is triggered by a separate system

Question 21

What is the maximum acceptable fuel tender pressure?

Answer 21

50PSI

Question 22

What does illumination of the MASTER VALVE advisory light on the pressure refuelling panel indicate to you?

Answer 22

The valve is closed.

Question 23

What does illumination of the FUELLING ON caution light in the cockpit indicate to you? Can we transfer fuel when the FUELLING ON caution light is illuminated?

Answer 23

the refuel/defuel selector on the refuelling panel is not in the off position and fuel transfer is not possible.

Question 24

What is the useable capacity of the main tanks in lbs and litres

Answer 24

5678lbs, 3161L

Question 25

What is the useable capacity of the AUX tanks in lbs and litres

Answer 25

4566lbs, 2542L

Question 26

How is engine cross feed accomplished?

Answer 26

Strictly speaking there is no true engine cross feed-The Dash - 8 is able to transfer fuel from one Main tank to the other via the fuel Transfer system. The motive flow for the fuel transfer is provided by the 115V AC Auxiliary Pumps when the transfer switch in the cockpit Js selected 10 either left or right. The Aux pump in the donor tank, pumps fuel from the donor collector bay, into the receiving collector bay

Question 27

How is fuel quantity measured?

Answer 27

There are six capacitance type fuel probes in each main Lank and two in each auxiliary tank. These send DC signals to the master quantity fuel gauges in the cockpit, which in turn supplies a signal (o the repeater gauges located in the refueling panel in the right (No: 2) engine nacelle.

Question 28

In the case of a DC power failure what do the cockpit fuel gauges indicate?

Answer 28

Fall to zero

Question 29

In the case of a DC power failure what do the nacelle fuel gauges indicate?

Answer 29

The last quantity sent from the cockpit gauges.

Question 30

Where is fuel temperature measured?

Answer 30

after the fuel/oil heat exchanger, prior to the engine driven pump

Question 31

What is the purpose of the surge bay?

Answer 31

It provides venting and pressurisation for the main and aux tanks and collector bay in all flight attitudes.

Question 32

What happens to fuel which enters the surge bay?

Answer 32

during flight any fuel which is spilled into the surge bay is returned via the vent float valve to the main tank. Ram air form 2 NACA vents provide positive pressure to the tank which forces fuel up the standpipe, through the vent float and into the main tank
During refuelling any fuel which enters the surge bay can escape through the NACA vents.

Question 33

How many fuel drains are there and where are they located?

Answer 33

8 in total, one in each aux tank, collector tank, main tank and surge bay.

Question 34

If the 3% check is outside 3% then how can this be rectified?

Answer 34

Conduct a magnastick check of fuel onboard. It must be conducted on level ground

Question 35

What could cause a ENG FUEL PRESS warning light? Is there anything one can do?

Answer 35

Failure or blockage of the of the boost ejector pump in the collector bay. Switch on the boost pump.

Question 36

What does ENG FLTR BYPASS caution indicate?

Answer 36

one of the two fuel filters is blocked or about to be blocked.

Question 37

Is electrical power required for the pressure refuelling system?

Answer 37

Yes

Question 38

Where does the pressure refuelling system get its power? And how is it indicated in the cockpit?

Answer 38

DC power is supplied to the panel via the battery bus, transfer valves open lights illuminate in the cockpit.

Question 39

During refuelling are the dump valves open or closed, Why?

Answer 39

Open, as the fuel must be able to escape, as well as the air in the tank in case of shut off failure.

Question 40

What power is required to defuel the aircraft?

Answer 40

DC power via the battery bus to open the valves and AC power to drive the AUC pumps. If AC unavailable suction defueling is required.

Question 41

When is AUX fuel transfer required? After takeoff during the scan prior to after takeoff checklist.

Answer 41

After takeoff during the scan prior to after takeoff checklist.

Question 42

If an AUX pump failed how could we transfer fuel from the aux tank?

Answer 42

The transfer would not be possible. Both pumps must be switched off to avoid imbalance.