OIL SCAVENGE SYSTEM - DESCRIPTION AND OPERATION

** ON A/C NOT FOR ALL

1. Component Location

FIN	FUNCTIONAL DESIGNATION	ZONE	ATA REF
** ON A/C NOT FOR ALL
4041EM	MAGNETIC CHIP COLLECTOR-OIL PUMP, BEARINGS 5 & 6	400	73-11-42
4042EM	MAGNETIC CHIP COLLECTOR-OIL PUMP, BEARING 4	400	73-11-42
4043EM	MAGNETIC CHIP COLLECTOR-OIL PUMP, MAIN GEARBOX	400	73-11-42
4044EM	MAGNETIC CHIP COLLECTOR-OIL PUMP, ANGLE GEARBOX	400	73-11-42
4045EM	MAGNETIC CHIP COLLECTOR-OIL PUMP, BEARING 3	400	73-11-42
4046EM	MAGNETIC CHIP COLLECTOR-OIL PUMP, FAN DRIVE GEAR SYSTE	400	73-11-42

** ON A/C NOT FOR ALL

2. System Description

Oil Distribution System ** ON A/C NOT FOR ALL

A. Magnetic Chip Collectors

(1) The No. 5 and No. 6 bearing magnetic chip collector is located on the lubrication and scavenge oil pump at approximately the 8 o'clock position.

(2) The No. 4 bearing magnetic chip collector is located in the tube (LR40) near the High Pressure Turbine (HPT) case at approximately the 7 o'clock position.

(3) The main gearbox magnetic chip collector is located on the lubrication and scavenge oil pump at approximately the 8 o'clock position.

(4) The angle gearbox oil pump magnetic chip collector is located on the lubrication and scavenge oil pump at approximately the 8 o'clock position.

(5) The No. 3 bearing magnetic chip collector is located on the lubrication and scavenge oil pump at approximately the 8 o'clock position.

(6) The fan drive gear system magnetic chip collector is located on the lubrication and scavenge oil pump at approximately the 8 o'clock position.

B. Lubrication and Scavenge Oil Pump

(1) The lubrication and scavenge oil pump sends pressurized oil from the oil tank to the engine bearings, seals, gears and accessory drives. The pump also sends scavenge oil back to the oil tank.

(2) The lubrication and scavenge oil pump connects to the front of the main gearbox at the 7 o'clock position.

(3) The pump has seven positive displacement gear-type pump stages. Each stage is turned by the MGB at a speed proportional to N2.

(4) The seven pump stages are:

A lubrication main pressure stage that sends oil to the main oil filter
Six scavenge stages that scavenge oil from the engine compartments that follow, and send it to the oil tank deaerator:
FDG and No. 1, 1.5 and 2 bearings
No. 3 bearing
Angle gearbox
Main gearbox and deoiler
No. 4 bearing
No. 5 and 6 bearings.

(5) The lubrication and scavenge oil pump has chip collectors that remove metal particles from the scavenge oil to find problems with oil-lubricated components. The collectors are found at the inlets of five scavenge stages that receive oil through external tubes.

(6) The lubrication and scavenge oil pump has a relief valve that limits the maximum main oil pressure.

(7) The main oil filter housing is included in the lubrication and scavenge oil pump housing.

C. Engine Oil Scavenge System

(1) The engine oil scavenge system sends back the hot lubrication oil to the oil tank through the lubrication and scavenge oil pump.

(a) The oil that is sent back is used by the engine oil distribution system to lubricate and decrease the temperature of the engine's main bearings and gearboxes.

(b) The lubrication and scavenge oil pump has six scavenge pump stages that are used to pull oil from the:

Front bearing compartment
No. 3 bearing compartment
No. 4 bearing compartment
No. 5 and 6 bearing compartment
Main gearbox
Angle gearbox.

(d) The oil tank deaerator removes the air from the scavenge oil and lets the hot, deaerated scavenge oil flow into the oil tank.

(e) The engine oil scavenge system has six magnetic chip collectors that catch ferrous metal particles in the scavenge oil.

(f) The lubrication and scavenge oil pump housing has five chip collectors, one for each of the scavenge oil lines that go into the pump. These lines cycle scavenge oil from:

The front bearing compartment (No. 1, 1.5, 2 and FDG)
No. 3 bearing compartment
No. 5 and 6 bearing compartment
Main gearbox
Angle gearbox.

1 The No. 4 bearing compartment chip collector is located on the No. 4 bearing scavenge line.

(g) The scavenge oil flows around the magnetic chip collectors and is pumped to the deaerator in the oil tank.

(h) The six chip collectors are bayonet-type plugs that can be removed and examined at regular time intervals or on condition.

(i) The collectors are in housings with self-closing check valves, so there is no oil leakage when a chip collector is removed.

(j) The six magnetic chip collectors are line replaceable units.

[Rev.10 from 2021] 2026.04.01 03:41:57 UTC