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

( 1 0 ) E S - 3 7 . LOW PRESSURE COMPRESSOR

CONTINUED

RUBS OR BINDS WHEN TURNED BY

H A N D , RUBBING OR BINDING IS

F E L T WHEN TUBEAXIAL FAN BLADES

O R LEFT COOLING FAN BLADES ARE

TURNED BY HAND AND MORE THAN

ONE HALF OF ACCESSORY GEARBOX

( A G B ) AND MAIN OIL PUMP

MAGNETIC PLUGS ARE COVERED WITH

M E T A L 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 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 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 bearing, 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

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 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 at least

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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