EFFECTIVITY
ALL CFM56 ENGINES
CFMI PROPRIETARY INFORMATION
CFM56-ALL
TRAINING MANUAL
BASIC ENGINE
PARTICULARS
BORESCOPE INSPECTION
Page 30
Sep 03
THE HIGH PRESSURE COMPRESSOR (HPC)
(ALL) :
Borescope ports.
There are 9 plugged borescope ports on the lower stator
case, at approximately the 5 o’clock position, and they
are numbered S1 thru S9, where S1 is the most forward.
Ports S1, S3, S5, and S6 have a 10mm diameter.
Ports S2, S4, S7, S8 and S9 have an 8mm diameter.
S7, S8 and S9 plugs have a particular design. They are
double plugs.
CAUTION: MAKE SURE TO FOLLOW THE
PROCEDURE IN THE AIRCRAFT MAINTENANCE
MANUAL (AMM) WHEN YOU REMOVE PLUGS S7, S8
AND S9.
The inner thread engages the HPC rear stator case,
while the outer thread is tightened on the HPC case.
A spring-loaded system enables the outer plug to drive
the inner plug.
Both inner and outer plugs have specific torque values.
Special tools.
Deep-well socket.
In case the shaft of borescope plugs S7, S8 or S9
breaks, remove the inner plug with a deep-well socket,
using the six flats at the end of the shaft.
IMPORTANT : WHEN RE-INSTALLING PLUGS S7, S8
OR S9, BE SURE TO APPLY THE RECOMMENDED
LUBRICANT TO THE THREADS AND CAREFULLY
FOLLOW THE TORQUING PROCEDURES IN
THE AMM .
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