LOW PRESSURE COMPRESSOR RUBS OR BINDS WHEN TURNED BY HAND AND MORE THAN ONE HALF OF ACCESSORY GEARBOX (AGB)

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3-2. TROUBLESHOOTING

(9) ES-36. LOW PRESSURE COMPRESSOR

h. LOW PRESSURE COMPRESSOR

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RUBS OR BINDS WHEN TURNED BY

HAND AND MORE THAN ONE HALF OF

ACCESSORY GEARBOX (AGB) AND MAIN

O I L PUMP MAGNETIC PLUGS ARE

C O V E R E D WITH METAL CHIPS.

This section contains troubleshooting to locate and correct the cause(s)

of low pressure compressor rubbing or binding when turned by hand, when

more than one half of the AGB and main oil pump magnetic plugs are

covered with metal chips. The low pressure compressor is mechanically

coupled to the low pressure turbine rotor in the rear engine

subassembly. If there is damage to the low pressure compressor or

position No. 1 or 2 bearing in the forward enqine module, or to the low

pressure turbine rotor or position No. 5 bearing in the rear engine

subassembly, binding will be felt when the low pressure compressor is

turned by hand. The AGB acts as an oil sump to collect oil scavenged

from bearings in the forward engine module and rear engine subassembly.

The main oil pump pumps the hot oil from the sump to the engine oil

cooler. The reduction gearbox (RGB) oil return line feeds dlrectly into

the oil pump passage that houses the magnetic plug. The only possible

source of metal chips on the oil pump magnetic plug is the RGB. The

symptoms described above indicate two separate failures. The art on the

following pages provides an overview of the systems described above.

Refer to these pages along with in-text art while performing

troubleshooting.

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