EFFECTIVITY
ALL CFM56 ENGINES
CFMI PROPRIETARY INFORMATION
CFM56-ALL TRAINING MANUAL
LOW PRESSURE
TURBINE
BORESCOPE
INSPECTION
Page 148
Sep 03
LOW PRESSURE TURBINE (LPT)
(ALL) :
The LPT features long span blades. Moving the probe in
and out enables a full-length inspection, which always
starts at the blade platform.
Index the N1 rotor, and turn it CW (ALF) to see the L/E
and concave side.
Turn it CCW (ALF) to see the T/E and convex side.
Stage 1 blades.
Inspection of the leading edges and the concave sides of
the stage 1 LPT blades can be done during inspection of
the HPT blade trailing edges.
(-2, -3, -5A) : Borescope plugs S17, S18, are removed
and an initial overall inspection, using the yellow probe,
may be performed to evaluate the blade condition.
(-5B, -5C, -7B) : Borescope plugs S16, S17, are removed
and an initial overall inspection, using the yellow probe,
may be performed to evaluate the blade condition.
(ALL) : Use probes 2, 3 and 4 (yellow, green and blue)
to inspect the blade roots and tips.
(-2, -3, -5A, -5B, -7B) :
Stage 2 thru 4 blades.
(-5C) :
Stage 2 thru 5 blades.
(-2, -3, -5A) :
These three stages are viewed respectively through ports
S20, S21 and S22.
(-5B, -7B) :
These three stages are viewed respectively through ports
S18, S19 and S20.
(-5C) :
These four stages are viewed respectively through ports
S18, S19, S20 and S21.
(ALL) :
Through a given nozzle stage port, it is possible to view
the T/E of the previous stage blade, and the L/E of the
current stage blade.
Use probes 2, 3 and 4. To obtain a better evaluation of
the defects, use probe 1 (black) where possible.
The trailing edge of the last stage blades can be
inspected through an instrumentation boss on the turbine
frame.
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