LOW PRESSURE COMPRESSOR RUBS OR BINDS WHEN TURNED BY HAND, RUBBING OR BINDING IS FELT WHEN TUBEAXIAL FAN BLADES OR LEFT COOLING FAN BLADES ARE TURNED BY HAND

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3-2. TROUBLESHOOTING - CONTINUED'

h. LOW PRESSURE COMPRESSOR

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E S - 3 4 . LOW PRESSURE COMPRESSOR

CONTINUED

RUBS OR BINDS WHEN TURNED BY

H A N D , RUBBING OR BINDING IS FELT

W H E N TUBEAXIAL FAN BLADES OR

L E F T COOLING FAN BLADES ARE

TURNED BY HAND AND MORE THAN ONE

H A L F OF MAIN OIL PUMP MAGNETIC

P L U G IS COVERED 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, and

rubbing or binding when the tubeaxial fan blades or left cooling fan

blades are turned by hand, when more than one half of the main oil pump

magnetic plug is 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 engine 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 power turbine and reduction gearbox (RGB) are

coupled mechanically through the power shaft. If there is damage to the

power turbine, rear engine subassembly position No. 6A or 6B bearings,

or RGB bearings and/or gears,

binding w1ll be felt when the tubeaxial

fan blades or left cooling fan blades are turned by hand. The RGB oil

return line feeds directly 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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