EFG

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CTC-201-190-02
EFFECTIVITY
79-21-10 Page 5
ALL CFM56-5B ENGINES FOR A319-A320-A321
ENGINE SYSTEMS Jan 03

CFMI PROPRIETARY INFORMATION
CFM56-5B TRAINING MANUAL

EFG
LUBRICATION UNIT
Supply filters.
In the supply circuit, downstream from the pressure pump, oil flows through the supply system which includes, first, the main oil supply filter.
A sensor, installed in between the upstream and downstream pressures of the supply filter, senses any rise in differential pressure due to filter clogging.
If the filter clogs, an electrical signal is sent to the aircraft systems for cockpit indication.
A by-pass valve, installed in parallel with the filter, opens when the differential pressure across the valve is greater than the spring load.
The oil then flows through the back-up filter and goes to the pump outlet.
The back-up filter is a metallic, washable filter.
During normal operation, the oil flow, tapped at the main supply filter outlet, washes the back-up filter and goes back to the supply pump inlet, through a restrictor.
The main filter is discardable and secured on the lube unit cover by a drain plug.
To prevent the filter element from rotating when torquing the drain plug, a pin installed on the filter element engages between two ribs cast in the lube unit cover.

EFG

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CTC-201-193-02
EFFECTIVITY
79-21-10 Page 7
ALL CFM56-5B ENGINES FOR A319-A320-A321
ENGINE SYSTEMS Jan 03

CFMI PROPRIETARY INFORMATION
CFM56-5B TRAINING MANUAL
EFG
LUBRICATION UNIT
Scavenge circuit.
In the scavenge circuit, the oil/air mixture is pumped from each engine sump by a dedicated pump, and passes through separate scavenge screens, installed on plugs.
Between the forward sump and AGB screens and their respective scavenge pumps, there is a connection with a pressure relief valve to allow the oil supply flow to enter the scavenge circuit, in case of overpressure.
The scavenge pumps downstream oil flows to a common outlet, and then to the Master Chip Detector (MCD).
Internal lube unit lubrication is through a built-in system using engine oil from the supply circuit.

EFG

.
CTC-201-191-02
EFFECTIVITY
79-21-10 Page 9
ALL CFM56-5B ENGINES FOR A319-A320-A321
ENGINE SYSTEMS Jan 03

CFMI PROPRIETARY INFORMATION
CFM56-5B TRAINING MANUAL
EFG
LUBRICATION UNIT
Scavenge screen plugs.
The scavenge screen plugs have threaded inserts for the installation of magnetic bars which serve as metal chip detectors during troubleshooting.
These magnetic bars enable maintenance staff to identify a particular scavenge circuit that may have particles in suspension in the oil.
Note: The magnetic bars can only be used with the A/C on ground and must be removed after troubleshooting.
　
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