Fuel¶
Fuel: 1 General¶
The fuel system includes: - One electrical pump and one jet pump in each of two tanks - Vent system - Fuel quantity indicating system - Refuel/defuel system with associated controls and indicators. REFUELING PANEL OVERWING REFUELING CAP VENT SURGE TANK RH WING TANK REFUEL DEFUEL FEEDER COMPARTMENT LH WING TANK VENT SURGE TANK OVERWING REFUELING CAP ACCESS DOORS CONNECTOR
Fuel: 2 Tanks¶
Two tanks receive fuel, one in each wing. Tanks are integral part of the wing structure. The maximum fuel capacity is : per tank total Volume 3 185 l 6 370 l Weight (density 0.785) 2 500 kg 5 000 kg An additional volume in each tank enables a 2 % fuel thermal expansion without spillage. Each tank has two access doors on the upper wing skin. These four doors at each tank extremity enable access to the interior and essential equipment.
Water drainage are at the low points of each tank. Drainage operation can be performed up to 3 ° ground slope. The temperature sensor is in the left feeder compartment. Temperature appears on MFD.
Fuel: 3 Vent System¶
1) TANKS The vent system ensures positive pressure in the entire flight envelope. Each fuel tank is ventilated via an individual vent duct and also with a vent float valve connected to a 100 l surge tank in the outer section of the wing. A flush NACA inlet connects surge tank to atmosphere and avoids icing obstructions. A surge tank collects fuel and enables fuel return to the wing tank via the vent duct. The vent system also provides protection for the tanks in case of accidental spillage during refueling. 2) WING CENTER BOX The wing center box over the fuselage does not store any fuel. This box crossed by two fuel pipes, enables engine feed and tanks refueling. Ventilation and drainage prevents fuel vapor concentration. VENT SURGE TANK LH WING FUEL TANK AIR INTAKE WING CENTER BOX DRAINS DRAIN RH WING FUEL TANK ANTI SURGE RIB
Fuel: 4 Engine Feed¶
Refer to SCHEMATICS In normal conditions, each wing tank supplies their associated engine. The flight crew can monitor the fuel consumption for each engine with the fuel flow and fuel used parameters which are displayed on the MFD ENGINE page and EWD Permanent Data window. To prevent negative or lateral 'g' factor effect, a 200 l feeder tank always full of fuel is embedded in each tanks. One electrical pump and one jet pump are installed per feeder tank. High pressure fuel from the Hydro Mechanical Unit (HMU) activates the jet pump through the control of a motive flow valve. Note Each electrical pump is able to supply one engine in the entire flight envelope. In normal operation, the electrical pump is only used to start the engine. After start, electrical pump is automatically shut down. If jet pump pressure drops below 5 psi, the electrical pump automatically supplies the engine. An electrically operated actuator controls the crossfeed valve. This valve enables both engines to be fed from one side or one engine to be fed by either tank and avoid unbalance situation. Crossfeed valve indication is on both Fuel panel and MFD. When the crossfeed valve is open, a cyan “FUEL X FEED” label appears on memo panel display and indication appears on the MFD system page. In this case, the two electrical pumps start automatically. It is possible to use only one fuel tank by switching off the opposite pump pushbutton. For crossfeed valve improper operation, label “FUEL X FEED” flashes on the memo panel display when: - Both electrical fuel pumps are OFF - Both electrical fuel pumps are ON - Electrical pump 1 is OFF with fuel quantity of tank 1 greater than fuel quantity of opposite tank - Electrical pump 2 is OFF with fuel quantity of tank 2 greater than fuel quantity of opposite tank. At fuel outlet of each tank, a fire handle controls an associate fuel LP valve. When a fuel tank is at low level, the associated electrical fuel pump starts automatically (fuel quantity less than 160 kg or feeder tank not full).
Fuel: 5 Quantity Indicating¶
The fuel quantity indicating system informs the crew of the quantity of fuel available in each tank during flight. The quantities are processed by Fuel Control Unit (FCU) and displayed on MFD.
The fuel tank capacity measurement system provides values in terms of weight. The system uses the fundamental relationship between the dielectric constant of the fuel and its density. Capacitance probes installed in tanks provide a signal proportional to the weight of fuel in the tanks. Six probes are in each tank. They provide electrical signal to the Fuel Control Unit (FCU). FCU processes the signals and provides left and right fuel quantities to the avionic system. FCU contains two independent channels (one per tank). The accuracy on the total fuel indication, on ground, with attitude within -3 ° and +1 ° of pitch is : Fuel Level Range 0 kg - 1 000 kg 1 001 kg - 3 000 kg 3 001 kg - 5 000 kg Accuracy +/- 100 kg +/- 130 kg +/- 150 kg For all other ground and flight conditions, outside this pitch envelope, accuracy of fuel indications will be degraded. On ground, in the case of failure of the quantity indicating system, two magnetic level indicators in each tank through the lower wing skin, provide fuel quantity in cm. Tables provide fuel weight with corrections established for aircraft attitude and fuel density (Refer to PRO.NOP.NSU.28.3.4 Use of Manual Magnetic Indicators)
Fuel: 6 Refuel-Defuel System¶
The Refueling Control Panel (RCP) in the RH main landing gear fairing controls all refueling operations. The single refueling connector, in RH leading edge, enables complete refueling in about 16 min min. The refueling flow of both wing tanks is about 24 m³/h with a maximum refueling pressure of 50 psi. The refueling connector is connected with two refuel valves, one for each tank. The refuel valves are just under the refueling connector. A Solenoid controls this valve. When aircraft electrical power is off, two latches, on each side of refuel valves, enable manual control of refuel valves. If both latches are pulled, as soon as fuel pressure is detected, both refuel valves open. From the valves outlets, pipes transfer fuel to diffusers. These diffusers enable the fuel to enter into the tank without turbulence. High level detection involves two different controls : In normal operation, the FCU system achieves high level detection. When the high level tank quantity is reached, the associated tank refuel valve is shut. When the high level is reached in a tank (for a zero bank angle), the associated high level light on the refuel panel comes on and the corresponding refuel valve is shut. One overfiller point per tank enables refuel by gravity of wing tanks. The system could be used to defuel the aircraft by applying a 11 psi suction to the connector and with tank refuel valves open.
Fuel: 1 Fuel Panel¶
FUEL PUMP ENG 1 LP VALVE ENG 2 LP VALVE PUMP X FEED OFF RUN FEED LO PR FEED LO PR OFF RUN 1 2 4 1 2 3 3
1 PUMP pb Controls electrical pump and jet pump motive flow valve in each tank. Pb pressed in When jet pump delivery low pressure detection (engine not running or jet pump pressure drop): - Automatic electrical pump activation - Controls open the jet pump motive flow valve but remains close until a sufficient pressure applies. 30 s after HP fuel pressure is available and the 8.5 psi pressure switch detects the normal jet pump functioning, electrical pump is automatically turned off. RUN Comes on green when electrical pump activates. It is automatically done when jet pump pressure drops below 5 psi. OFF (Pb released) The electrical pump is deactivated and the jet pump motive flow valve is closed. OFF light comes on white. 2 LP VALVE Position Indicator Indicates the position of the LP valve. Each fire handle controls its associated valve. IN LINE Flow bar comes on green. The valve is open. CROSS LINE The valve is closed, flow bar comes on green and crosses the system flow line. Note During transient phases (opening or closing) flow bars goes off. 3 FEED LO PR Light In case of fuel delivery pressure below 4 psi, the light comes on amber. Also the caution message FEED LO PR is displayed on EWD with a Master Caution light and a Single Chime. This indicates pump failure or fuel starvation. 4 X FEED pb Controls the operation of the fuel crossfeed valve. IN LINE (Pb pressed in) The flow bar comes on green in line. The valve is open. Both electrical pumps are automatically actuated. CROSS LINE (Pb released) The flow bar comes on green and crosses the system flow line. The valve is closed. Note During transient phases (opening or closing), flow bar goes off. If both bars remains off permanently, it indicates a valve fault.
Fuel: 2 Refueling Panel¶
FUEL QTY VALVE OPEN HIGH LEVEL LH RH LH RH REFUELING INC DEC SELECTED QTY OFF REFUEL DEFUEL NORM SHUT OPEN LH LH RH REFUEL VALVES SURGE VALVE ATR 72 ONLY SHUT OPEN ON OFF TEST MAIN L/G LT RH 1 2 3 4 5 6 7 8 9
1 TEST pb Pressing the test button will test the display lines and the lights.
2 HIGH LEVEL light If high level sensor is reached (maximum refueling quantity), the light comes on amber. The respective refuel valve closes automatically. 3 REFUEL VALVES position light If the refuel page is open, the light comes on blue. They come off during the fuel circuit test, to inform the valves are closed. 4 REFUEL VALVES switches Control the operation of the valves for each tank. They are guarded at NORM. NORM Automatic fueling logic controls valves, depending on position of the Mode selector sw and quantity preselection. In case of high level detection by the FCU, valves automatically close. OPEN In case of Mode selector sw in the refuel or defuel position and the high level sensor not submerged valves are open. SHUT Valves close regardless of the Mode selector sw position. Note In case of vent surge tanks overflow detection, refuel valves close automatically regardless of switch position. 5 SELECT QTY indication Set the preselector to control the quantity fo automatic refueling. The counter displays the preselected total fuel quantity. 6 INCREASE / DECREASE switch Used to select fuel quantity requested on board. 7 FUEL QTY indication Three displays for left, right and preselected fuel quantity. 8 Mode selector switches Controls the operating mode for automatic fueling and REFUEL VALVES switches activation in manual operation. OFF Refuel valves are closed, switches shut off. REFUEL Refuel valves may be operated by auto refueling logic (REFUEL VALVES switches on NORM) or manual refueling operation. DEFUEL Refuel valves may be operated by manual defueling operation. With the mode selector in DEFUEL position and REFUEL VALVES in the OPEN position, all level protections are inhibited. 9 SURGE VALVE During suction, drainage provides air vent of the refuel line. OPEN The surge valve opens. Mode selector sw must be in OFF position. SHUT The surge valve is closed.
Fuel: 3 Fuel Indication¶
MFD
0 XFEED FUEL TANK OFF 270 KG 1170 TEMP °C 31 FUEL FLOW KG/H 4.5 1+2 KG/MN °C -4 RUN KG 1170 TEMP °C 29 CLOG 2 1 3 4 5 6 7 8 9 10
1 Fuel Flow Indication (per engine) In normal operation, values are displayed in green with kg/h unit For invalid data, dashes appear in amber For unit or aircraft type discrepancy, “LAB” flag appears in amber.
2 Fuel Feed Indication Green arrow: normal transfer Cyan horizontal line: no fuel feeding Grey arrow: status not correct. 3 Fuel Flow 1+2 In normal operation, values are displayed in green with kg/min unit For invalid data, dashes appear in amber For unit or aircraft type discrepancy, “LAB” flag appears in amber. 4 Engine LP Valve Indication Green in line: valve open Cyan horizontal line: valve closed Amber line at 45 °: valve position not correct Amber cross lines: valve signal not valid. 5 XFEED Valve Cyan in line: valve open Green vertical line: valve closed Amber line at 45 °: valve position not correct Amber cross lines: valve signal not valid. 6 Fuel tank quantity indication In normal operation, values appear in green. Readout resolution is: - 1 kg when fuel quantity is below 200 kg - 10 kg when fuel quantity is equal or above 200 kg. For invalid data, dashes appear in amber For unit or aircraft type discrepancy, “LAB” flag appears in amber. 7 Fuel Tank Temperature Indication In normal operation appears in green with °C unit For invalid data, dashes appears in amber. 8 Engine Feed Pumps Indication Green: electrical pump ON (“RUN” legend inside) White: electrical pump OFF (“OFF” legend inside) Amber rectangles: electrical pump OFF but the pump is running Amber cross lines: pump signal not valid. 9 Fuel Temperature Indication Fuel temperature and arrow appear in: - Red: equal or lower than -54 °C (red arrow and reverse video red temperature) - Amber: From -53 °C to 0 °C - Green: 1 °C to 49 °C - Amber: 50 °C to 99 °C - Red: Equal or higher than 100 °C (red arrow and reverse video red temperature) - Amber dash: Invalid temperature.
10 Fuel Clog Caution In case of an excessive pressure loss in the fuel filter, amber “CLOG” label appears.
Fuel: 4 Crossfeed Indication¶
MFD
NO SMKG SEAT BELT ENG AIRFRAME HORN SIDE WINDOWS PROP 1 1 2 2 1 2
ANTI ICING FUEL XFEED DE ICING 1 ITEM DISPLAY COLOR DISPLAY DESCRIPTION 1 FUEL XFEED Cyan In normal operation X FEED Valve open. FUEL XFEED Flashes Cyan In case of abnormal crossfeed valve operation, the label X FEED flashes when: - Both electrical fuel pumps are off - Both electrical fuel pumps are on - Electrical pump 1 is off and tank 1 fuel quantity greater than opposite tank - Electrical pump 2 is off and tank 2 fuel quantity greater than opposite tank. FUEL XFEED Amber Imbalance detection.
Fuel: 5 FU-FOB Indicator¶
EWD 88888 11111 TAT SAT KG FOB GW °C °C H 52 12 52 H 13 : FUEL USED KG 8888 KG 8000
13 FT -12 -21 1 2 1 Fuel Used Indication (per engine) In normal operation, values are displayed in green with kg unit. For invalid data, dashes appear in amber. In the case of FU incoherence, “LAB” flag appears in green. Note The Fuel Used can be reset by use of the EFIS Control Panel (EFCP) via the Virtual Control Panel (VCP) window / PERF/ Take-off Data page. 2 Fuel On Board Indication In normal operation, values are displayed in green with kg unit. For invalid data, dashes appear in amber. In the case of FOB incoherence, “LAB” flag appears in green.
Fuel: 1 Electrical Supply¶
EQUIPMENT DC BUS SUPPLY (C/B) AC BUS SUPPLY (C/B) ENG 1 Electrical pump DC ESS BUS (on lateral panel 121VU — C/B FUEL/FUEL FEED/ENG1/ ELEC PUMP) NIL - Pressure sw controlling electrical pump activation/ disactivation and motive flow valve opening/closure - FUEL FEED Pressure sw DC ESS BUS (on lateral panel 121VU — C/B CTL and C/B FUEL/FUEL FEED/ ENG1/CTL & CAUTION) NIL Fuel LP valve DC BUS 1 (on lateral panel 121VU — C/B FUEL/LP VALVES/ENG1/ MOTOR 1) HOT EMER BAT BUS (on lateral panel 121VU — C/B FUEL/LP VALVES/ENG1/ MOTOR 2) NIL Fuel LP valve position ind. DC EMER BUS (on lateral panel 121VU — C/B UEL/LP VALVES/ENG1/IND) NIL ENG 2 Electrical pump DC ESS BUS (on lateral panel 121VU — C/B FUEL/FUEL FEED/ENG2/ ELEC PUMP) NIL - Pressure sw controlling electrical pump activation/ disactivation and motive flow valve opening/closure - FUEL FEED Pressure sw + IND DC ESS BUS (on lateral panel 121VU — C/B FUEL/FUEL FEED/ ENG2/CTL & CAUTION) NIL
EQUIPMENT DC BUS SUPPLY (C/B) AC BUS SUPPLY (C/B) Fuel LP valve DC BUS 2 (on lateral panel 121VU — C/B FUEL/LP VALVES/ENG2/ MOTOR 1) HOT EMER BAT BUS (on lateral panel 121VU — C/B FUEL/LP VALVES/ENG2/ MOTOR 2) NIL Fuel LP valve position ind. DC EMER BUS (on lateral panel 121VU — C/B FUEL/LP VALVES/ENG2/IND) NIL Refuel Control panel GND HDLG BUS (on lateral panel 121VU — C/B FUEL/FUELING CTL & IND) NIL FCU Channel 1 DC ESS BUS (on lateral panel 121VU- C/B FUEL/FCU CHAN 1) NIL FCU Channel 2 DC ESS BUS (on lateral panel 121VU — C/B FUEL/FCU CHAN 2) NIL Crossfeed valve DC ESS BUS (on lateral panel 121VU — C/B FUEL/FUEL FEED/X FEED) NIL Note On ground, when battery is off and refuel door open, for aircraft servicing, GND HDLG BUS supplies FCU.
Fuel: 1 FUEL FEED LO PR-Alert¶
CONDITION VISUAL AURAL Engine feed low pressure - MC light flashing amber - FUEL FEED LO PR amber message on EWD - Associated FEED LO PR amber light on overhead panel SC
Fuel: 2 FUEL LO LVL-Alert¶
CONDITION VISUAL AURAL Fuel quantity indication below 160 kg (352 lb) - MC light flashing amber - FUEL LO LVL amber message on EWD - Associated tank LO LVL amber message on Engine SD page - Associated tank is amber on MFD with fuel quantity in amber (quantity between 160 kg (352 lb) and 50 kg (110 lb)) or in red reverse video (quantity below 50 kg (110 lb)) SC
Fuel: 3 FUEL LO LVL - Secondary-Alert¶
CONDITION VISUAL AURAL Feeder tank not full - MC light flashing amber - FUEL LO LVL amber message on EWD - Associated feeder tank is amber on MFD SC
Fuel: 4 FUEL CLOG-Alert¶
CONDITION VISUAL AURAL Pressure difference between filter inlet and outlet over 25 psi. - MC light flashing amber - ENG FUEL CLOG amber message on EWD - CLOG amber message flag on ENG Secondary SD page SC
Fuel: 5 Jet Pump Pressure-Alert¶
CONDITION VISUAL AURAL Jet pump pressure drop (below 5 psi) - RUN green light on overhead panel. NIL
Fuel: 6 FUEL MISMATCH-Alert¶
CONDITION VISUAL AURAL Difference between fuel quantity computed by FMS and fuel quantities processed by the FCU is greater than 200 kg (440 lb) during more than 10 s (on ground) or 60 s (in flight). - MC light flashing amber - FUEL MISMATCH amber message on EWD SC
Fuel: 7 FUEL UNBALANCED-Alert¶
CONDITION VISUAL AURAL Discrepancy greater than 200 kg (440 lb) between left and right tanks fuel quantities. - MC light flashing amber - FUEL UNBALANCED amber message on EWD SC
Fuel: 1 General¶
HMU TO ENGINE No 1 FUEL FLOWMETER HP SHUT OFF VALVE (CONDITION LEVER) FUEL CLOG PRESS SW FUEL FILTER BY PASS HP PUMP TEMP SENSOR FUEL HEATER OIL MOTIVE FLOW VALVE FEED LO PRESS LP VALVE (FIRE HANDLE) FUEL INDICATOR PROBES LO LVL PUMP PRESS SW ELEC PUMP FEEDER JET PUMP TEMP SENSOR LEFT MAIN TANK LEFT FEEDER TANK HMU TO ENGINE No 2 FUEL FLOWMETER HP SHUT OFF VALVE (CONDITION LEVER) BY PASS HP PUMP TEMP SENSOR FUEL HEATER OIL MOTIVE FLOW VALVE FEED LO PRESS FUEL INDICATOR PROBES LO LVL PUMP PRESS SW ELEC PUMP FEEDER JET PUMP RIGHT MAIN TANK RIGHT FEEDER TANK ANTI SURGE RIB ANTI SURGE RIB ENG JET PUMP ENG JET PUMP X FEED VALVE
FUNCTIONAL ABSTRACTION - complete feed/crossfeed system
LEFT MAIN TANK -> LEFT FEEDER TANK -> [LP PUMP] -> [HP PUMP/HMU] -> ENGINE 1
^ | | |
| +--> low-press +--> filter / clog sensing
| sensing +--> fuel heater / temp sensing
|
+---------------- refuel/defuel manifold ----------------+
|
RIGHT MAIN TANK -> RIGHT FEEDER TANK -> [LP PUMP] -> [HP PUMP/HMU] -> ENGINE 2
| |
+------ [X-FEED VALVE] ------+
Motive-flow valves drive tank jet-pump transfer. Fuel-quantity probes span
main and feeder tanks; flowmeters feed the engine/fuel indications.