12.9 (ATA 28) FUEL
12.9.1 Introduction
Fuel is contained in two integral main wing tanks designated No. 1 and No. 2. The fuel systemprovides for indicating, storing, venting, fuel feeding and scavenging, refueling/defueling, andtransferring. Only tank to tank transfer is available; there is no engine crossfeed capability. Theaircraft may be gravity or pressure refueled.
12.9.2 General
A fuel gauging system supplies quantity data to the flight compartment and refuel/defuel panelfor display. Fuel quantity may also be checked on the ground by use of the magnetic dipsticks.
Each wing tank includes a surge bay and a collector bay. The left tank supplies fuel to the leftengine and the optional Auxiliary Power Unit (APU). The right tank supplies fuel to the rightengine. A vent system keeps the air pressure in the fuel tanks between structural limits.
Fuel can be transferred between the tanks for lateral balancing or for fuel management. A singlepoint pressure refuel/defuel system shares selected common components with the fuel transfersystem. Gravity refueling may also be done through two overwing fuel filler points.
Dash8 - Q400 - Fuel
Page 1
12.9.3 Controls and Indications - Fuel
Dash8 - Q400 - Fuel
Page 2
Figure 12.9-1 Engine and System Integrated Displays Control Panel (ESCP)
ENG
SYSNAV
PFD
MFD1
ENG
NAVSYS
PFD
MFD2
ELEC SYS
ENGSYS
FUEL SYS
DOORS SYS
ALL TEST
NORM1 2
EFISATT/HDG
SOURCEADC
OFF
ED BRT
NORM1 2
SOURCE
EFIS
1 2 3
Dash8 - Q400 - Fuel
Page 3
ESCP CALLOUTS PERTAINING TO FUEL ITEMS
1. MFD 1 REVISION SELECTOR (4 position, rotary action)
TURN - selectable positions are PFD, NAV, SYS, ENG- ESCP provides the pilot with the ability to select any page on the MFD1 and to control
the EIS reversion after display failures
2. FUEL SYS PUSHBUTTON (momentary action)
PUSH - provides a display of the fuel system page on the MFD (upper area) with MFD 1 orMFD 2 set at SYS
- there is no action with another push
PUSH AND HOLD - (with both MFDs not set to SYS)- fuel system page shown on the Engine Display (ED)- ED images are shown again when the pushbutton is released
3. MFD 2 REVISION SELECTOR (4 position, rotary action)- same as MFD1 selector except selects pages on MFD2
Dash8 - Q400 - Fuel
Page 4
Figure 12.9-2 Fuel Control Panel
Dash8 - Q400 - Fuel
Page 5
FUEL CONTROL PANEL CALLOUTS
1. TANK 1 AUX PUMP SWITCHLIGHT (alternate action)
PUSH - ON segment (green)- activates auxiliary fuel pump in left collector bayPUSH - ON segment (out)- deactivates auxiliary fuel pump in left collector bayON segment (green) without pushing- auxiliary fuel pump has been activated by the fuel transfer system (TANK 1 to TANK 2)
2. FUEL TRANSFER SWITCH (three position, lever latched)
TO TANK 1 - activates transfer system to transfer fuel from tank No. 2 to tank No. 1
CENTER - transfer system deactivated
TO TANK 2 - activates transfer system to transfer fuel from tank No. 1 to tank No. 2
3. TANK 2 AUX PUMP SWITCHLIGHT (alternate action)- same as TANK 1 AUX PUMP switchlight, except auxiliary pump in No. 2 collector bayON segment (green) without pushing- auxiliary fuel pump has been activated by the fuel transfer system (TANK 2 to TANK 1)
Dash8 - Q400 - Fuel
Page 6
Figure 12.9-3 MFD2 Fuel Page - Quantity Indications
FLAPDEG
35
1050
35
1
3
5
1
4
3
2
4
QTY3 4
5
670
1
2
LBSx1000
QTY3 4
5
670
1
2
LBSx1000
FUELTRANSFER SW
VALVE VALVE
TOTANK1
TOTANK2
TANK1AUX PUMP
TANK2AUX PUMP
SW SWOFF ON
TOTAL FUEL4800LBSTANK +20C
CLOSED CLOSEDOFF
HYD PRESS HYD QTYPK
STBYPSI x 1000 % x 1000
BRK 1 2 3 1 2 34
2
0
Dash8 - Q400 - Fuel
Page 7
MULTI FUNCTION DISPLAY (MFD) FUEL PAGE CALLOUTS
1.AUXILIARY FUEL PUMPS SWITCH ANNUNCIATOR
OFF segment (white text surrounded by a white box)- the respective TANK 1 or TANK 2 AUX PUMP switchlight is not in the depressed positionON segment (reverse video, black text on green background)- the respective TANK 1 or TANK 2 AUX PUMP switchlight is in the depressed position
- white dashes replace the text (without a box), when no data is available
2. DIGITAL DISPLAY OF FUEL TANK TEMPERATURE (digital value and TANK segment in white, C segment in blue)- indicates temperature in left collector bay with a sign- if using JET B/JP-4 and TANK temperature is more than 35C, maximum altitude is
20.000 ft- indicates from -99 to +99 in 1 increments- digits are replaced by white dashes when the data is not valid
3. ANALOG DISPLAY OF FUEL QUANTITY- gives an analog readout of fuel quantity in the left and right tanks
QTY segment (white)KGx1000 segment (cyan)Scale and digit segments (white)- scale marks and digits are removed when the parameter is not validPointer segment (white) - normalPointer segment (yellow) - during an imbalance condition- removed when the parameter is not valid
4. TANK AUXILIARY PUMP PRESSURE STATUS INDICATORCircle segment (white outline with black fill) - low or no pressure Circle segment (white outline with green fill) - normal pressure
5. DIGITAL DISPLAY OF TOTAL FUEL QUANTITY(digital value and TOTAL FUEL in white, KG segment in blue)- total fuel quantity given in KG- indicates from 0 to 15000 in 5 KG increments- digits are replaced by white dashes when the data is not valid
Dash8 - Q400 - Fuel
Page 8
Figure 12.9-4 MFD Fuel Page - Transfer Indications
FLAPDEG
35
1050
35
11 2
QTY
3 4
5
6
70
1
2
LBSx1000
FUEL
TRANSFER SW
VALVE VALVE
TOTANK1
TOTANK2
TANK1AUX PUMP
TANK2AUX PUMP
SW SW
OFF ON
TANK +20C
HYD PRESS HYD QTY
PKSTBY
PSI x 1000 % x 1000
BRK 1 2 3 1 2 34
2
0
TOTAL FUEL4000 LBS
QTY
3 4
5
6
70
1
2
LBSx1000
OPENOPEN
OFF
Dash8 - Q400 - Fuel
Page 9
MULTI FUNCTION DISPLAY (MFD) FUEL PAGE CALLOUTS
1. FUEL SHUTOFF VALVE ANNUNCIATOR- indicates shutoff valve state in response to a crew transfer requestVALVE segment (white)CLOSED segment (white in upper white outline rectangle)- indicates fuel transfer valve is closedOPEN segment (reverse video, black text on green in lower rectangle)- indicates fuel transfer valve is open- when the valve is neither fully closed nor fully open (typical case during valve transition),
nothing is displayed- three white dashes are displayed instead of the CLOSED and OPEN indication when no
data is available
2. FUEL TRANSFER SWITCH INDICATION- indicates the position of the FUEL TRANSFER switch on the FUEL CONTROL panelTRANSFER SW segment (white)TO TANK 1 and TO TANK 2 segment (white)Triangle segment (white in white outline rectangle)- pointing towards the left indicates that a transfer is active from right to left- pointing towards the right indicates that a transfer is active from left to right- in case of inconsistency (transfer fault towards both sides), both triangles are displayed
as the data is received- three white dashes are displayed when no data is availableOFF segment (white in white outline rectangle)- indicates no fuel transfer is requested
Dash8 - Q400 - Fuel
Page 10
Figure 12.9-5 ED Fuel Parameters
75%MCR
75%MCR
NH%RPM
TRQ%
NH%RPM
FFPPH
1020
FFPPH
PROPRPM
ITTC
NL%RPM
74
NL%RPM
74
FUELPSIOILC50 50
PSIOILC75 50
SAT +22C
75 75
850 850
755
[ BALANCE ]
BLEED BLEED
755
1020+18
1625+18
LBSC
- - - -
92.3 92.3
3
11
2
3 44
Dash8 - Q400 - Fuel
Page 11
ED CALLOUTS PERTAINING TO FUEL ITEMS1. FUEL FLOW INDICATOR
(FF and digital value in white, PPH or KG/H in blue)- indicates from 0 to 9990 in 10 PPH or 5 KG/H increments- digits are replaced by white dashes when the data is not valid
2. [BALANCE] MESSAGE (yellow, flashings)- indicates a fuel imbalance condition is detected by the left or right Fuel Gauging Com-
puter (FGC1 or FGC2)3. LEFT/RIGHT FUEL TANK QUANTITY DIGITAL VALUE
(Digital value white, yellow if imbalance, KG in blue)- total fuel quantity given in KG- indicates from 0 to 9990 in 5 KG increments- digits are replaced by white dashes when the data is not valid
4. LEFT/RIGHT FUEL INLET TEMPERATURE DIGITAL VALUE(Digital value in white, yellow, or red, C segment in blue)- indicates temperature of the fuel with a sign, after it has passed through the Fuel Oil
Heat Exchanger (FOHE)- indicates from -99 to +99 in 1 increments- digits are normally displayed in white- digits will turn yellow if the temperature is below 0C- digits will turn red if the temperature is above 71C- digits are replaced by white dashes when the data is not valid- continuous operation with fuel heater outlet temperature below 0C or above 71C is pro-
hibited.
Dash8 - Q400 - Fuel
Page 12
Figure 12.9-6 Magnastick Operation Locator
IN USE
STOWED
1
1
3
3
2
4
2
4
1
2
4
A
A
Dash8 - Q400 - Fuel
Page 13
MAGNETIC DIPSTICK CALLOUTS AND OPERATION
1.MAGNATIC DISPSTICK MAGNET
2.FLOAT MAGNET
3.FUEL LEVEL IN MAIN TANK
4. CALIBRATED MAGNETIC DIPSTICK- the magnetic dipsticks give an alternate means to measure the fuel quantity when the aircraft
is on the ground- the magnetic dipstick is accessed at the bottom of the wing- when the rod is released, it moves slowly down until the rod magnet is attracted by the float
magnet- the fuel quantity is shown in US gallons or in liters- the reading will indicate full whenever the tank is more than 700 U.S. Gal (2700 L)- the reading will indicate empty whenever the tank is less than 100 U.S. Gal (400 L)
Dash8 - Q400 - Fuel
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Figure 12.9-7 Refuel/Defuel Panel (1 of 2)
A
NO
TE
Co
mp
on
en
t lo
cate
d o
nrig
ht
Na
celle
on
ly.
A
PR
EC
HE
CK
OP
EN
CL
OS
E
DU
MP
VA
LV
E O
PE
NT
AN
K 1
RE
FU
EL
SH
UT
OF
FT
AN
K 2
OF
FP
RE
SE
LE
CT
DE
FU
EL
DE
FU
EL
PR
ES
EL
EC
TR
EF
UE
L
RE
FU
EL
31
00
31
00
62
00
LB
FU
EL
QT
Y
TA
NK
1
TA
NK
2
PR
ES
EL
TE
ST
INC
R
RE
SE
TD
EC
R
GR
OU
ND
CR
EW
JA
CK
TA
NK
1T
AN
K 2
RE
FU
EL
SH
UT
OF
FT
AN
K 1
DU
MP
VA
LV
E O
PE
NT
AN
K 2
98
8
7766
5
4 3 2 1
Dash8 - Q400 - Fuel
Page 15
REFUEL/DEFUEL PANEL CALLOUTS
1.REFUEL/DEFUEL INDICATOR (RDI)
2. PRESELECTED FUEL QUANTITY- desired amount of fuel for processing a refueling or defueling operation, as set by the
INCR/DECR switch
3. TANK 2 ACTUAL FUEL QUANTITY
4.TANK 1 ACTUAL FUEL QUANTITY
5. MASTER VALVE INDICATOR LIGHT (amber)- master refuel/defuel valve is closed- turning selector switch from OFF will open the valve and light will go off
6. TANK 1/TANK 2 DUMP VALVE LIGHT (amber)- vent/dump valve related tank is open
7. TANK 1/TANK 2 REFUEL SHUTOFF VALVE LIGHT (white)- level control shutoff valve is closed (i.e. no fuel is flowing into related tank)
8. TANK 1/2 LEVEL CONTROL SHUTOFF VALVE SWITCHES (three position spring loaded away from PRECHECK, toggle switch)
PRECHECK - simulates full fuel signal to the High Level Control Unit (HLCU) stopping refu-eling of related tankOPEN - opens related Refuel/Defuel/Transfer shutoff valve for refueling or defuelingCLOSE - closes related Refuel/Defuel/Transfer shutoff valve to stop fuel flow
9. REFUEL/DEFUEL SELECTOR SWITCH (5 position)
REFUEL or DEFUEL- manual refueling or defueling continues until the selected switch is setto OFF, the HLCU detects a full tank, or the level control shutoff valve switches are placed inthe CLOSE positionPRESELECT REFUEL or DEFUEL - refuel/defuel operation stops automatically, when thepreselected levels are reachedOFF - power removed from the refuel/defuel control panel
Dash8 - Q400 - Fuel
Page 16
Figure 12.9-8 Refuel/Defuel Panel (2 of 2)
A
NO
TE
Co
mp
on
en
t lo
cate
d o
nrig
ht
Na
celle
on
ly.
A
PR
EC
HE
CK
OP
EN
CL
OS
E
DU
MP
VA
LV
E O
PE
NT
AN
K 1
RE
FU
EL
SH
UT
OF
FT
AN
K 2
OF
FP
RE
SE
LE
CT
DE
FU
EL
DE
FU
EL
PR
ES
EL
EC
TR
EF
UE
L
RE
FU
EL
31
00
31
00
62
00
LB
FU
EL
QT
Y
TA
NK
1
TA
NK
2
PR
ES
EL
TE
ST
INC
R
RE
SE
TD
EC
R
GR
OU
ND
CR
EW
JA
CK
TA
NK
1T
AN
K 2
RE
FU
EL
SH
UT
OF
FT
AN
K 1
DU
MP
VA
LV
E O
PE
NT
AN
K 2
10
11
Dash8 - Q400 - Fuel
Page 17
REFUEL/DEFUEL PANEL CALLOUTS (contd)10. INCR/DECR SWITCH (three position, spring loaded to center)
- used to set the desired amount of fuel for processing a refueling or defueling operationINCR or DECR - the current PRESEL display value on the RDI will increase/decrease by 10
kg- this is repeated 10 times after which the current PRESEL display will increase/decrease
by 100 kg- indicates from 0 5800 kg- the displayed preselect value will never rise above the total fuel quantity when the refuel
mode status indicates a defuel operation is in progress- the displayed preselect value will never fall below the total fuel quantity when the refuel
mode status indicates a refuel operation is in progress- four seconds after the INCR/DECR switch is stable at the neutral position, the automatic
refuel/defuel function will start- if refueling/defueling is in process and the INCR/DECR switch is moved out of its neutral
position, the refuel/defuel operation will stop and will restart four seconds after the INCR/DECR switch activity is stopped
11. TEST/RESET SWITCH (three position, spring loaded to center)TEST - starts display test- displays a checkerboard pattern for 2 1 seconds, followed by an inverse checkerboard
pattern for 2 1 seconds and finally, followed by all segments turned off for 2 1 sec-onds
RESET - for maintenance purposes- selecting RESET during refueling/defueling will cause the operation to stop and ABORT
will be displayed in the PRESEL window. The PRESEL value will then display the currenttotal fuel quantity. To restart refueling/defueling, the PRESEL value will have to beincrease or decrease using the INCR/DECR switch
Dash8 - Q400 - Fuel
Page 18
12.9.4 Fuel - Indications
Fuel quantity and temperature data is shown in white on the Engine Display (ED) and the FuelPage of the Multi Function Display (MFD). White dashes replace the digits or simulated dials ifthe data is not valid or not available.
A Fuel Quantity Computer (FQC) uses nine capacitance type fuel probes in each tank to deter-mine the total fuel quantity. The fuel quantity of each tank is shown in digital form on the bottomcenter of the Engine Display (ED). The Fuel Page of the Multi Function Display (MFD) alsoshows the fuel quantity of each tank on two simulated analog dials and below that the total fuelquantity in digital form. The fuel quantity can be shown in kilograms (KG). The fuel flow for eachengine is shown in digital form on the ED in units of KG/H.The fuel temperature (C) in the left collector tank is shown in digital form on the MFD Fuel Page,just below the left fuel quantity dial. The engine inlet temperature of the fuel after it has passedthrough the Fuel/Oil Heat Exchanger (FOHE) for the left and right engines is shown in digitalform on the bottom of the ED, just below the related fuel tank quantity. The digits are shown inwhite with a sign, and change to yellow or red if the temperature is not in the preset range. A Cunit is shown between the two inlet temperatures.
The fuel quantity of each tank is also shown on the refuel/defuel panel located at the back under-side of the right nacelle. One magnetic dipstick on the underside of each tank can also be usedon the ground to give an independent mechanical indication of the fuel quantity in liters or U.S.gallons. The magnetic dipstick is a calibrated rod with a magnet attached to the top. It moveswithin a tube that extends vertically from the bottom of the fuel tank. A float moves up and downon the outside surface of this tube to match the fuel level in the tank. The float contains a magnetthat is attracted to the magnet on the magnetic dipstick, holding the dipstick at that level.
Dash8 - Q400 - Fuel
Page 19
Figure 12.9-9 Fuel Tank Layout
LE
GE
ND
1.
Su
rge
Ba
y.2
. O
verw
ing
Fill
er
Ca
p.
3.
Ma
in T
an
k.4
. C
olle
cto
r B
ay.
5.
Pre
ssu
re R
efu
el/D
efu
el C
on
tro
l Pa
ne
l.
12
34
12
35
4
Dash8 - Q400 - Fuel
Page 20
12.9.5 Storage And Distribution
There are two integral (wet) wing tanks that extend laterally from the fuselage to the rib justinboard of the ailerons (Figure 12.9-9). Each wing tank is divided into three sections:
Surge bay Main tank Collector bay
The surge bay is located between the two ribs inboard of the aileron. The main tank extends fromthe surge bay to the fuselage and collector bay. The collector bay is located at the inboard andaft part of the wing tank. Fuel is contained in the main tanks and the collector bays.
Total usable fuel from the tanks is 5,318 kg. The maximum lateral imbalance permitted betweentanks is 272 kg. Water drain valves in the low points of the surge bays, main tanks, and collectorbays are located on the underside of the wings.
The surge bay is used for main tank venting and fuel recovery. Two outboard float vent valvesand one inboard vent line, control the pressure between the related surge bay and main tank(Figure 12.9-10). The two float vent valves, located near the top of the tank, open and closedepending on the fuel level in the main tank. Each surge bay is vented through integral stand-pipes to two separate NACA vents on the bottom of the wings. During flight, any fuel that mayspill into the surge bay, is returned to the tank by the reduced pressure in the main tank, as fuel isused.
The collector bay supplies engine fuel regardless of aircraft attitude. Fuel tank scavenging takesplace using scavenge ejector pumps in each tank which draw fuel from tank low points, to keepthe collector bay full. A primary ejector pump in the collector bay then provides a constant low-pressure fuel supply to the engine. High-pressure motive flow is used to operate the scavengeand primary ejector pumps.
Flapper check valves are located at the base of each collector bay, and select ribs. They ensuregravity fed fuel flow into the collector bay if the scavenge flow is not sufficient.
The related #1 TANK or #2 TANK FUEL LOW caution light will come on if:
park brake is off related collector bay level drops below approximately 150 kg. related engine is operating.
Dash8 - Q400 - Fuel
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Figure 12.9-10 Fuel Tank Venting
Dash8 - Q400 - Fuel
Page 22
12.9.6 Engine Fuel FeedFuel to each engine is fed from the collector tank, from a primary ejector pump or an AC drivenauxiliary pump, and delivered to the engine driven pump (Figure 12.9-11). If the engine drivenpump inlet pressure drops below a preset limit, the related #1 or #2 ENG FUEL PRESS cautionlight comes on.An AC (Variable Frequency) auxiliary pump in each collector bay serves as a back up source offuel boost pressure for takeoff and landing, and in case the related primary ejector pump doesnot supply the necessary fuel pressure. Related TANK 1 or TANK 2 AUX PUMP switchlights onthe FUEL CONTROL TRANSFER panel control the auxiliary pumps manually (Figure 12.9-12).A TANK 1 or TANK 2 AUX PUMP switch indicator on the MFD Fuel Page shows the position ofthe switchlight. When the pump is supplying sufficient boost pressure, the TANK 1 or TANK 2AUX PUMP light on the Fuel Page will turn green, and the related ON switchlight segment turnsgreen.The engine feed shutoff valve closes when the related PULL FUEL/HYD OFF handle, on the FireProtection Panel (FPP), is pulled (Figure 12.9-12). Advisory lights on the FPP show when thevalve is open or closed.
The fuel is filtered and heated by Fuel Oil Heat Exchanger (FOHE) before entering the FMU. Ifthe fuel filter becomes blocked, fuel bypasses the filter. The #1 or #2 FUEL FLTR BYPASS cau-tion light will come on if a related bypass is impending.
Dash8 - Q400 - Fuel
Page 23
Figure 12.9-11 Engine Fuel Feed Schematic
fs number
P
P
SU
RG
EB
AY
NA
CA
VE
NT
S
OU
TB
OA
RD
SC
AV
EN
GE
EJE
CT
OR
MID
WIN
GS
CA
VE
NG
EE
JEC
TO
R
AF
TS
CA
VE
NG
EE
JEC
TO
R
FO
RW
AR
DS
CA
VE
NG
EE
JEC
TO
R
EN
GIN
E F
EE
DS
HU
T-O
FF
VA
LV
E
EN
GIN
E F
EE
DP
RE
SS
UR
E S
WIT
CH
AP
U F
EE
DLN
E (
TO
AP
U)
DR
YB
AY
TO
PR
IMA
RY
EJE
CT
OR
PU
MP
TE
MP
ER
AT
UR
ES
EN
SO
R
INLE
TS
TR
AIN
ER
FLO
AT
SW
ITC
H
AU
XIL
IAR
YP
UM
PA
PU
SH
UT
-OF
FV
ALV
E
AIR
CR
AF
T
C LE
NG
INE
AU
XIL
AR
Y P
UM
PP
RE
SS
UR
E S
WIT
CH
MO
TIV
E F
LO
WC
HE
CK
VA
LV
E
CO
LLE
CT
OR
BA
Y
FLA
PP
ER
VA
LV
ES
(TY
PIC
AL)
Dash8 - Q400 - Fuel
Page 24
Figure 12.9-12 Engine Fuel Feed Operation
IFC 1IFC 2
FOHE
PULL FUEL/HYD OFF
ENGINE 1
FAULTA
FAULTB
EXTGAFT BTL
FWD BTL
OPEN CLOSED
HYD
VALVESFUEL
BLO
TESTDETECTIO
LEGEND
ELECTRICALSIGNAL
TOTANK
1
TOTANK
2
TANK 1AUX PUMP
ON
TRANSFER
FUEL CONTROL
ON
VALVE
IFC 1IFC 2
CLOSED CLOSEDTO
TANK 1TO
TANK 2
TRASFER SW
FUEL
TANK2AUX PUMP
TANK1AUX PUMP
OFFSW SW
TANK +15CTOTAL FUEL
4800 LBS
7
QTY
LBSx10000
1
2
3
5
6
4
QTY
LBSx10000
1
2
3
5
7
6
4FUELOIL PSIC50 50
OIL PSIC75 50LBS
SAT +22C
C24002400+18+18
OFF
P
T
#1 ENGFUEL PRESS
#1 TANKFUEL LOW
P
VALVE
Dash8 - Q400 - Fuel
Page 25
Figure 12.9-13 Fuel Transfer Schematic
OPENOPEN
QTY
3 4
5
6
70
1
2
x1000
QTY
3 4
5
6
70
1
2
LBSx1000
TRANSFER SWTO
TANK1
TO
TANK2
TANK1
AUX PUMP
TANK2
AUX PUMP
TOTAL FUEL4000 LBS
VALVE
SW SW
VALVEFUEL
OFF OFF
TANK +20C
LEVEL CONTROL
SOLENOID
LEVEL CONTROL
SHUTOFF VALVE
COLLECTOR
BAY
COLLECTOR
BAY
AUXILIARY
PUMP
FUEL TRANSFER
SHUTOFF VALVE
FUEL CONTROLTRANSFER
TOTANK
1
TOTANK
2
TANK 2AUX PUMP
TANK 1AUX PUMP
ON
LEGEND
ELECTRICALSIGNAL
LBS
IFC 1IFC 2
PRESSURE SWITCH
FROM REFUELING
ADAPTER
Dash8 - Q400 - Fuel
Page 26
12.9.7 Fuel Transfer
Fuel can be transferred from one tank to the other to correct fuel imbalances or for fuel manage-ment. If the Fuel Quantity Computer (FQC) detects a fuel imbalance of more than 272 kg, a yel-low [BALANCE] message flashes just above the FUEL legend of the ED. The message will flashuntil the imbalance is corrected. An imbalance condition will also be shown on the Fuel Page bythe analog quantity dials changing to solid yellow.
A TRANSFER switch on the FUEL CONTROL TRANSFER panel controls the fuel transfer sys-tem (Figure 12.9-13). When the TRANSFER switch is selected, the auxiliary pump in the donortank operates automatically to pump fuel to the receiver tank. A signal from the operating pumpcauses the related ON switchlight segment to turn green. Electrically operated fuel transfer shut-off valves open for fuel transfer and close when the transfer is stopped. Fuel transfer indicationsare also shown on the MFD Fuel Page. Once selected, fuel transfer will continue until deselectedby the flight crew or until a high-level sensor in the wing tank which is receiving fuel detects anoverfill condition, which automatically halts fuel transfer. Fuel cannot be transferred if the FUEL-ING ON caution light is on. The FUELING ON caution light is on if the refuel/defuel access dooris open.
Dash8 - Q400 - Fuel
Page 27
Figure 12.9-14 Refueling Schematic
fs number
PR
EC
HE
CK
OP
EN
CLO
SE
DU
MP
VA
LV
E O
PE
N
RE
FU
EL S
HU
TO
FF
OF
FP
RE
SE
LE
CT
DE
FU
EL
DE
FU
EL
PR
ES
ELE
CT
RE
FU
EL
RE
FU
EL
3100
3100
6200
LB
FU
EL
QT
Y
TA
NK
1
TA
NK
2
PR
ES
EL
TE
ST
INC
R
RE
SE
TD
EC
R
GR
OU
ND
CR
EW
JA
CK
TA
NK
1T
AN
K 2
RE
FU
EL S
HU
TO
FF
TA
NK
1
DU
MP
VA
LV
E O
PE
NT
AN
K 2
HIG
H L
EV
EL
SE
NS
OR
VE
NT
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MP
VA
LV
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L C
ON
TR
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SH
UT
OF
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FU
EL T
RA
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HU
TO
FF
VA
LV
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CO
LLE
CT
OR
BA
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CT
OR
BA
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VE
LC
ON
TR
OL
SO
LE
NO
ID
RE
FU
EL/
DE
FU
EL
AD
AP
TE
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RE
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EL/D
EF
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LS
HU
TO
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LV
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ND
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RIC
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SIG
NA
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TA
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Dash8 - Q400 - Fuel
Page 28
12.9.8 RefuelingThe refuel/defuel panel controls all refuel and defuel operations (Figure 12.9-14). Access to thepanel is gained through a flush door on the rear underside of No. 2 nacelle. DC power must beavailable for refueling. The FUELING ON caution light will come on when the refuel/defuel dooris open with electrical power supplied. Refueling can be accomplished either automatically (PRE-SELECT REFUEL), or manually (REFUEL).When the rotary selector is turned to the PRESELECT REFUEL or REFUEL position, the MAS-TER VALVE CLOSED light goes out to show that the refuel/defuel shutoff valve is open (Figure12.9-15,16). The refuel/defuel shutoff valve will close when the refuel/defuel door is closed,regardless of the rotary selector position. During pressure refueling, fuel pressure opens a vent/dump valve in each tank to vent the tanks through the surge bay. For automatic refueling, thedesired quantity is selected adjacent the PRESEL display on the Refuel/Defuel Indicator (RDI),by using the INCR DECR toggle switch (Figure 12.9-17). When the selected quantity is reached,the level control shutoff valve automatically stops fuel flow to the related tank. The PRECHECK,OPEN, CLOSE switches must be set to OPEN for refueling.During manual refueling, the desired quantity in each tank is controlled by the PRECHECK,OPEN, CLOSE switches. The RDI will display the individual tank quantities. With the rotaryselector turned to the REFUEL position, refueling continues until the PRECHECK, OPEN,CLOSE switches are in the CLOSE position, the selector switch is turned to the OFF position, oruntil the high level sensors sense a full tank condition.When fueling is in progress, advisory lights on the refuel/defuel control panel indicate the positionof the fuel control valves. The amber DUMP VALVE OPEN indicator light comes on when therelated vent/dump valve opens. The vent/dump valve allows air to vent from the tank as it fills,and prevents damage should the tank overfill due to failure of both normal and backup shutofffeatures. In the latter case, fuel flows into the surge bay through the refuel vent valve and, if itreaches the height of the standpipes, is spilled overboard through the surge bay NACA vents.Two PRECHECK, OPEN, CLOSE switches test the automatic shutoff operation of the relatedhigh level control unit during refueling, ensuring operation of the overfill shut off system. With theswitch in the PRECHECK position a full tank is simulated for the related tank, and the high levelsensor shuts off refueling to that tank by closing the level control shut off valve. This causes therelated amber REFUEL SHUTOFF light to turn on. Refueling restarts when the switch isreleased. If DC power is lost during refueling, refueling stops.Gravity refueling can be done through the wing mounted gravity refuel adapter located on the topsurface of the wing (Figure 12.9-18).
Dash8 - Q400 - Fuel
Page 29
Figure 12.9-15 Refueling Operation (1 of 2)
TANK 1
INITIAL CONFIGURATION
PANEL SET TO INITIATE REFUELING
REFUELING IN PROGRESS
PRECHECK
OPEN
CLOSE
OFF
DEFUELREFUEL
4000400010000 LB
FUEL QTY
TANK 1
TANK 2
PRESEL
TEST INCR
RESET DECR
GROUND CREW JACK
TANK 1 TANK 2
REFUEL SHUTOFFTANK 1
DUMP VALVE OPENTANK 2
DUMP VALVE OPENTANK 1
PRESELECTDEFUEL
REFUEL SHUTOFFTANK 2
PRESELECTREFUEL
DUMP VALVE OPENTANK 1
REFUEL SHUTOFFTANK 2
PRESELECTDEFUEL
PRESELECTREFUEL
PRECHECK
OPEN
CLOSE
OFF
DEFUELREFUEL
3100310010000 LB
FUEL QTY
TANK 1
TANK 2
PRESEL
TEST I
RESET DECR
GROUND CREW JACK
TANK 1 TANK 2
REFUEL SHUTOFFTANK 1
DUMP VALVE OPENTANK 2
R
REFUEL SHUTOFFTANK 2
PRESELECTDEFUEL
PRESELECTREFUEL
PRECHECK
OPEN
CLOSE
DUMP VALVE OPEN
OFF
DEFUELREFUEL
FUEL QTY
TANK 1
TANK 2
PRESEL
TEST INCR
RESET DECR
GROUND CREW JACK
TANK 1 TANK 2
REFUEL SHUTOFFTANK 1
DUMP VALVE OPENTANK 2
LEGEND Light Off. Light On.
Dash8 - Q400 - Fuel
Page 30
Figure 12.9-16 Refueling Operation (2 of 2)
TANKS FULL
REFUELING COMPLETE
PRE-CHECK TEST (No. 1 TANK) DURING REFUELING
PRECHECK
OPEN
CLOSE
OFF
DEFUELREFUEL
4100420010000 LB
FUEL QTY
TANK 1
TANK 2
PRESEL
TEST INCR
RESET DECR
GROUND CREW JACK
TANK 1 TANK 2
REFUEL SHUTOFFTANK 1
DUMP VALVE OPENTANK 2
DUMP VALVE OPENTANK 1
PRESELECTREFUEL
PRESELECTDEFUEL
REFUEL SHUTOFFTANK 2
DUMP VALVE OPENTANK 1
REFUEL SHUTOFFTANK 2
PRESELECTREFUEL
PRESELECTDEFUEL
PRECHECK
OPEN
CLOSE
OFF
DEFUELREFUEL
5000500010000 LB
FUEL QTY
TANK 1
TANK 2
PRESEL
TEST INCR
RESET DECR
GROUND CREW JACK
TANK 1 TANK 2
REFUEL SHUTOFFTANK 1
DUMP VALVE OPENTANK 2
DUMP VALVE OPENTANK 1
REFUEL SHUTOFFTANK 2
PRESELECTDEFUEL
PRESELECTREFUEL
PRECHECK
OPEN
CLOSE
OFF
DEFUELREFUEL
FUEL QTY
TANK 1
TANK 2
PRESEL
TEST INCR
RESET DECR
GROUND CREW JACK
TANK 1 TANK 2
REFUEL SHUTOFFTANK 1
DUMP VALVE OPENTANK 2
Dash8 - Q400 - Fuel
Page 31
Figure 12.9-17 Refuel/Defuel Indicator Operation
Refuel Shutoff Valves are Closed
4 Seconds AfterINCR/DECR is
neutral
Move INC/DECRSwitch
Reset Switch
New Preselect
Tank 1 &Tank 2Fuel
quantitiesare
Updated
NewPreselectis entered
Reset Switch SetsPreselect = Total
Refuel ShutoffValves are ClosedFuel flow stopped
Total Fuel = Preselect.Refuel Shutoff Valves are Closed
Fuel flow stopped
PreselectRefuel
Completed
Automatic Fuel Shutoff
Shuttoff valves are opened
PreselectQuantity is set
to Total Quantity DECR
INCR
RESET
TEST
PRESEL
TANK 2
TANK 1
FUEL QTY
lblblb
630031803120
POWER ON
lblb
DECR
INCR
RESET
TEST
PRESEL
TANK 2
TANK 1
FUEL QTY
ABORT46504600
DECR
INCR
RESET
TEST
PRESEL
TANK 2
TANK 1
FUEL QTY
lblblb
1000050005000
DECR
INCR
RESET
TEST
PRESEL
TANK 2
TANK 1
FUEL QTY
lblblb
1000045004430
DECR
INCR
RESET
TEST
PRESEL
TANK 2
TANK 1
FUEL QTY
lblblb
1000031203120
5 Second Delay
Use INCR/DECR Switch to set
Preselect Quantity
Dash8 - Q400 - Fuel
Page 32
Figure 12.9-18 Overviewing Filler Cap
CLOSE
OPEN
FWD
A
A
Dash8 - Q400 - Fuel
Page 33
12.9.9 Defueling
When the rotary selector is turned to the PRESELECT DEFUEL position, the FGC closes therefuel/defuel valves to automatically stop defueling at the preset quantity. When the rotary selec-tor is turned to the DEFUEL position, defueling continues until the selector switch is turned to theOFF position. If AC (variable frequency) power is available, the related auxiliary fuel pump oper-ates to help the defueling process. Without an AC power source, suction defueling must be used.DC power is required for defueling regardless of AC power availability.
12.9.10 Limitations
The maximum refueling pressure is 50 psi, which gives a refueling flow rate of approximately 125 gallons per minute. A minimum of 20 psi refueling pressure is necessary for the system to oper-ate properly.
Dash8 - Q400 - Fuel
Page 34