B767/28/101 Fuel System
Boeing 767-200/300
Fuel System Training manual For training purposes only LEVEL 1
ATA 28
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Training manual
This publication was created by Sabena technics training department, Brussels-Belgium, following ATA ATA 104 specifications. specificati ons. The information in this publication is furnished for informational and training use only, and is subject to change without notice. Sabena technics training assumes no responsibility for any errors or inaccuracies that may appear in this publication. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of Sabena technics training.
Contact address for course registrations course schedule information Sabena technics training
[email protected]
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B767/28/101 Fuel System
1. INTRODUCTION. The boeing 767 fuel system includes the fuel tanks, a vent system, a fueling system, a feed system with automatic sumping, defueling valves, a fuel jettison system, and a fuel quantity indicating system (FQIS).
1.1. General. Fuel Tanks. All fuel for the engines and APU is stored within the wing. The three tanks, left main, right main, and center auxiliary are of wet wing construction. Baffle ribs in the main tanks control outboard flow. Outboard of both main tanks is a surge tank. The surge tanks contain overflow and prevent fuel spills. The surge tanks drain into the center auxiliary tank and are normally empty. Vent System. The vent system maintains near ambient atmospheric pressure within the tanks. A vent scoop in each wing creates a slightly positive pressure during flight to its associated surge tank. Vent channels connect each surge tank to the main and auxiliary fuel tanks. A flame arrester is mounted in both vent scoop tubes. Backup pressure relief valves are provided. Fueling System. The fueling system includes a manifold with six fueling valves inside the tanks and a fueling station on the left wing leading edge. The fueling valves are controlled by the fuel quantity indicating system (FQIS) to allow versatility in fueling operations. An overfill sensor in each surge tank terminates fueling operations should the tanks overfill. An overwing fill port is located on the upper wing surface for both main tanks. Pump priming and FQIS component washing is also accomplished during fueling. Feed System. The fuel feed system supplies fuel to the two main engines and the APU. Two AC boost pumps are installed in each main tank. Two AC override pumps are installed, one per side, in the center auxiliary tank. A bypass valve in each main tank allows suction flow from the main tanks. A DC pump pressure feeds the APU automatically when the AC pumps are not operating. Dual crossfeed
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FUEL SYSTEM
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valves interconnect the normally isolated left and right feed manifolds. This allows any tank to feed either engine if desired. Automatic jet pumps prevent water and contaminates from accumulating in tank low points and transfer remaining fuel into the main tanks from the center auxiliary tank after the main tanks are depleted to approximately one-half full. Defueling. The defueling valves interconnect the feed system and the fueling system. This allows defueling and fuel transfer operations on the ground only. Fuel Jettison. A fuel jettison system is installed to rapidly reduce the gross weight of the aircraft. Two jettison pumps operate along with the center override pumps, to jettison center auxiliary tank fuel overboard. Controls for the system are located on the flight deck. Fuel Quantity Indicating System (FQIS). The FQIS is a microprocessor controlled capacitance type fuel quantity measuring system. The FQIS requires only 28V DC power for operation. A direct digital display of fuel weight is provided in the flight compartment and at the fueling station. Tank units and compensators provide volume measurement. Densitometers, one in each tank, provide fuel density signals. The FQIS also controls the fueling valves to allow overfill protection and automatic fueling termination at preselected quantity levels. Measuring Sticks. Magnetic dripless type measuring sticks are mounted in the lower wing surfaces of each tank to provide an alternate method of determining fuel quantity.
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FUEL SYSTEM PANELS
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1.2. Fuel Components - Left Rear Spar.
1.3. Fuel Components - Right Rear Spar.
The following fuel system components are located on the left rear spar :
The following fuel system components are located on the right rear spar :
- Fueling valves (2 main, 1 center), - Left defueling valve, - Boost, override, and fuel jettison pump pressure switches, - Left engine fuel shutoff valve (spar valve), - FQIS wiring harness connections (left main and left center), - Left main tank densitometer connector, - APU DC pump, - APU fuel shutoff valve, - Left jettison transfer valve, - Fuel crossfeed valves, - Temperature bulb, - Left jettison nozzle valve.
- Fueling valves (2 main, 1 center), - Right defuel valve, - Boost, override, and fuel jettison pump pressure switches, - Right engine fuel shutoff valve (spar valve), - FQIS wiring harness connections (right main and right center), - Right main tank and center tank densitometer connectors, - Right jettison transfer valve, - Right jettison valve.
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RIGHT REAR SPAR - FUEL COMPONENTS
LEFT REAR SPAR - FUEL COMPONENTS EFFECTIVITY ALL
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2. FUEL TANKS. 2.1. Construction and Location. All three fuel tanks are constructed by sealing the primary wing structure with sealant. The tanks are formed by the front and rear spars, the top and bottom wing skins, and by selected wing ribs. Main Tanks. The left and right main tanks are located between rib 3 and rib 31 in both wings. Dry bays are located in both wing leading edges over the engine hot sections to prevent fuel leakage from contacting the engine. Rib 5 and rib 18 are sealed, and have free-swinging check valves in the bottom to allow inboard fuel flow while preventing outboard fuel flow. These fuel dams control flow to prevent uncovering the pump inlet ports, and to prevent fuel weight shifts. The main tanks may be fueled by use of an overwing port near the leading edge between rib 23 and rib 24. Center Auxiliary Tanks. The center auxiliary tank is between ribs 3 in the wing and through the fuselage. There is no dry bay in this tank. Surge Tanks. The surge tanks are located between rib 31 and rib 34 in both wings. These normally empty tanks are designed to contain overflow to prevent fuel spillage.
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Access. Access to all tanks and the dry bays is through oval cutouts in the lower wing surface. In selected cases (ribs 1, 2, 4, 5 and 9), openings in the rib allow access to adjoining rib sections. A cover panel is installed over the opening in rib 5, to prevent fuel slosh through the opening. The panel must be removed to gain access to the inboard tank area. The cutouts vary in size, with the smaller ones outboard. Other components, such as measuring sticks and pressure relief valves are installed on selected access doors. The center section has one access door in the lower right corner, located just forward of the right air conditioning bay area. Sump drains. Identical sump drain valves are located in the low point of both main tanks, both surge tanks, and in each side of the center auxiliary tank outboard of the S.O.B . rib. In addition, a sump drain valve with a tube attached is located inboard of each S.O.B. rib. These are accessed by use of a door in t he wing root fairing. There are a total of eight drain valves. These allow fuel sampling, and draining of residual fuel. In addition, the dry bay for the engine hot section has two drain holes with flame arresters.
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FUEL TANKS
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FUEL VENT SYSTEM AND FLOAT VALVES EFFECTIVITY ALL
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4. PRESSURE FUELING SYSTEM. In addition to fueling and defueling the airplane, the pressure fueling system primes the boost and override pumps.
4.1. General Configuration. Fueling, fuel transfer, and defueling are accomplished and controlled from a single fueling station located on the left wing. The fueling station includes a fueling control panel (P28) and two fueling adapters. Each fueling adapter has a cap. A light on the door provides illumination, and indication of station power.
Fueling Capabilities. Normal fueling is accomplished from the fueling station with 28V DC power. The fuel quantity indicating system (FQIS) interfaces with the fueling system to allow automatic fueling shutdown at preselected quantities or when the tanks are full by volume. Backup overfill protection is supplied by a separate card located in the P50 card file and a sensor in each surge tank.
The fueling manifold is located near the rear spar inside the tank. It includes six fueling valves, a manifold vacuum valve, two manifold drain valves, a pressure relief valve and two defuel valves. Fueling check valves prevent backflow. Pressure Fueling Valves. There are two fueling valves for each tank. These valves are fuel pressure actuated, solenoid controlled valves. The solenoid is controlled by the FQIS microprocessor through a switch on the P28 panel. A knurled knob on the valve allows the valves to be manually opened without solenoid power. Fuel Manifold Draining. The two manifold drain valves drain the manifold into the center auxiliary tank after fueling. These close during fueling to prevent undesired fueling flows. The single manifold vacuum valve vents air into the manifold. It closes during defueling to prevent sucking air into the manifold.
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PRESSURE FUELING SYSTEM EFFECTIVITY ALL
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FUELING STATION EFFECTIVITY ALL
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FQIS LOAD SELECT FUEL QUANTITY INDICATOR page 19 12 - 04 - 2012 rev : 1
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4.4. Overwing Fueling Ports. The overwing fueling ports provide a method of fueling main tanks without utilizing the pressure fueling station. The ports may also be used to inspect a portion of the tank visually. Location. Two ports, one on each wing, at wing station 785.2 between rib 23 and rib 24 are available. Access is from the wing leading edge. A grounding point for the nozzle is located close to the port. Filler Cap. The filler cap seals the fueling port. Venting is not provided. A lanyard prevents the cap from being lost when removed. Lift and rotate the handle to remove the cap. Fueling Port. The fueling port is installed using O-ring seals, a seal ring and a retaining nut. The tanks will contain 5925 gallons when fueled to the port level. The tanks will hold 6070 gallons when fueled with the pressure fueling system. The caps should not be removed when the mains are full to prevent spillage.
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OVERWING FUELING PORTS
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5.3. Motor-Actuated Valves. The motor-actuated valves on the engine feed system include the engine fuel shutoff valves (spar valves), the crossfeed valves, and the defuel valves. Each valve has three sub-assemblies; the valve body, an adapter and shaft assembly, and a 28V DC permanent magnet motor actuator. The valve bodies and actuators are interchangeable between installations.
B767/28/101 Fuel System
Actuator Replacement. The actuator is replaceable without defueling. It mounts to an adapter plate with 4 screws. It should be installed in the valve closed position. Do not loosen the three adjustment screws, because the valve closed alignment marks on the valve body are not visible outside of the tank. Realignment requires tank access.
Valve Body. The valve bodies are mounted in-line on the engine manifold, inside the tanks, using two couplings. The body has a 4 hole mounting flange, a thermal relief, and a splined operating shaft with a universal joint. One spline is missing to assure proper indexing on installation. The thermal relief valve is threaded to allow installation of a plug for pressure testing. Alignment marks indicate that the valve is closed, because the valve does not hard stop either open or closed. Adapter and Shaft Assembly. The adapter and shaft assembly is custom-fit to each installation. The assembly includes a mount plate, an adapter plate, and a shaft with a universal joint. The actuator and adapter have two splines omitted to assure proper indexing. Loosening three adjustment screws allows the adapter plate to be rotated in slots with respect to the mount plate. During the original installation of the adapter and shaft assembly, the adapter plate can be rotated with the actuator installed, and in the valve closed position, to align the marks on the valve body. Three screws on the adapter plate can be loosened to allow the alignment. Motor Actuator. All motor actuator on the fuel system are mounted in the wheel wells on the rear spar, are interchangeable, and are powered by 28V DC. A manual override lever allows the actuator to be operated without electrical power. This lever also indicates valve position. Cycle time between limits is approximately 2 to 3 seconds.
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MOTOR ACTUATED VALVES EFFECTIVITY ALL
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5.4. Automatic Sumping Jet Pumps. The automatic sumping jet pumps draw fuel and contaminates from the tank low points. They discharge near the boost and override pump inlets, allowing the contaminates to be drawn in and pass through the engine before an accumulation can occur. Physical Description/Features. Each of the six rib-mounted jet pumps has five inlet ports. A screened tube connects to each port to draw from the tank low point between stringers. In the center auxiliary tank, two of the inlets are longer than the rest to scavenge fuel from the bays inboard of the side of body rib. There is a connection for the motive flow to power the pump, and for discharge. Location and Installation. There are six jet pumps, three per side. The two main tank jet pumps are mounted on rib 3. The center auxiliary tank jet pumps are mounted on rib 2, one in each side. The housing is mounted to the rib. The pump assembly mounts to the housing on the opposite side of the rib.
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AUTOMATIC SUMPING JET PUMPS EFFECTIVITY ALL
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5.5. Transfer Jet Pumps. The transfer jet pumps are designed to siphon any residual fuel from the center auxiliary tank to the main tanks aft er the override pumps are turned off during normal operation (after the override pump low pressure lights come on). Location. One jet pump is located in each side of the center auxiliary tank, just inboard of the side-of-body rib. A float valve is located outboard of rib 3 in each main tank. Physical Description/Features. The pumps are of the jet aspirator type. The aft main tank boost pumps supply the motive force to power the two transfer jet pumps. A ball check valve prevents backflow through the induced port. Operation. Fuel pressure is present at the motive port whenever the aft main tank pumping units are operating. A float valve in each main tank closes the discharge port until the main tank is depleted to approximately one-half full. When the discharge port is open, motive flow aspirates fuel from the center tank through the induced port, and transfers this fuel to the main tanks through the discharge port. Operation is thus completely automatic, as a function of the float valve, and is unmonitored. To operationally check the transfer jet pumps, the auxiliary fuel tanks must contain at least 1,000 Kg. of fuel and each main tank must contain less than 9,000 Kg. of fuel. To verify operation of the float valves (closure), the auxiliary fuel tanks must contain at least 1,000 Kg. of fuel and each main tank must contain at least 11,500 Kg. of fuel.
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TRANSFER JET PUMPS
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ENGINE FUEL FEED SYSTEM AND OPERATION EFFECTIVITY ALL
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6. APU FUEL FEED SYSTEM. 6.1. General. The APU is normally fed from the left engine feed manifold. The right engine feed manifold may also be used when a crossfeed valve is open. When fuel pressure is unavailable from the engine feed manifold, an APU DC pump located on the left rear spar will automatically pressure-feed the APU. APU DC Pump. The APU DC pump draws fuel from the left main tank only. It operates on 28V DC power from the battery bus automatically. There are no controls in the flight compartment. A pressure switch on the pump inputs to the EICAS, which displays the maintenance message DC FUEL PUMP ON when appropriate. APU Fuel Shutoff Valve. The APU fuel shutoff valve is a 28V DC motor actuated unit that operates automatically when the APU is started or shut down. APU Fuel Supply Line. The fuel supply line is a solid aluminum tube routed through the left SOB rib into the dry center area and out the top to a special fitting between the top of the center section and passenger floor. This fitting connects a Kevlar braid one-piece plastic coated flex-line, a rigid aluminum shroud to contain flex-line leaks, and a drain line to the mast located aft of the left wheel well. The flex-line is laying inside the shroud unsupported. Access to the fitting for flex-line replacement requires removal of a section of the passenger floor.
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APU FUEL FEED SYSTEM EFFECTIVITY ALL
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28V DC BATT. BUS
L. AFT PRESS. SW.
L. FWD. PRESS. SW.
L. CENTER PRESS. SW.
FIRE HOT BATT. BUS M
M DC BOOST
AUTO LEFT FWD. BOOST PUMP SELECT ON APU ON
LOW PRESS. ENGINE BOOST PUMP
L. FWD. L. AFT L. CNTR.
PUMP
DC BOOST PUMP RELAY K191
APU ON
APU FUEL VALVE DISAGREE RELAY K192
N
6 sec.
APU FUEL VAL. (C)
FAULT NO PWR. IF DISAGREE OR TRANSIT
1 = CL. P > 3 psi
DC FUEL PUMP ON (M) EICAS COMPUTER
APU BOOST PUMP CONTROL AND OPERATION EICAS DISPLAY
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6.2. Defueling. Defueling and tank to tank fuel transfer operations are performed on the ground only. Two 28V DC permanent magnet motor actuated defuel valves, one in each main tank, connect the engine fuel feed manifold to the fueling manifold allowing defuel or transfer. The defuel valves are controlled by guarded switches at the fueling station. Defuel Valve. The defuel valve is identical to the engine fuel shutoff valve and crossfeed valve. The actuators and valve bodies are the same part number. The adapter and shaft is customized for each installation. A manual override on lever the actuator allows mechanical opening and closing of the valve and also indicates valve position.
B767/28/101 Fuel System
Tank-to-tank transfer. Tank-to-tank fuel transfer is the same procedure as pressure defueling. The appropriate boost or override pumps must be operating to provide sufficient pressure to actuate the fueling valve diaphragms. Open the fueling valves for the tank to receive the fuel and turn on the boost or override pumps for the tanks to be defueled. Monitor the quantity gages to determine progress. It is not necessary to connect fueling nozzles, or to turn the adapter cams to the DEFUEL position. Defuel valve position indication. A blue press-to-test light for each defuel valve indicates valve position. The light comes on when the valve is fully open, and remains on until the valve is fully closed.
Pressure defueling. Press-to-test the blue defuel valve lights after the fueling station has been powered. Turn the adapter cams to the DEFUEL position and connect the nozzles. Open the defuel valves. Turn on the appropriate boost or override pumps for the tank(s) to be defueled using the switchlights in the flight compartment. Suction defueling. Suction defueling of the main tanks is the same as pressure defueling of the tanks except the boost pumps are not used. Suction supplied from the defueling vehicle allows fuel flow through the bypass valves and defuel valves to the vehicle. Suction defueling of the center auxiliary tank is not possible.
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DEFUELING SYSTEM
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FUEL JETTISON SYSTEM AND OPERATION
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