EFFECTIVITY
ALL CFM56 ENGINES
CFMI PROPRIETARY INFORMATION
CFM56-ALL
TRAINING MANUAL
FAN AND
BOOSTER
BORESCOPE
INSPECTION
Page 86
Sep 03
FAN AND BOOSTER
(ALL) :
Booster rotor damage may occur after the engine
experienced an abnormal problem. The following list
provides examples of conditions where a complete
borescope inspection should be performed:
- Fan, or Low Pressure Compressor stall (this may
occur during engine deceleration).
- Foreign Object Damage (FOD) and suspected
bird ingestion.
- High level of N1 rotor vibration.
- N1 rotor overspeed.
- Heavy landing (acceleration above threshold limit).
Booster blade inspection areas.
There are 3 areas on the booster blades, which are
dimensionally defined using letters.
Area E :
- This area of the blade starts from the top of the
platform and extends toward the blade tip for
approximately 10 mm.
Refer to the AMM for precise area.
Area G :
- This area of the blade starts from the tip of the
blade and extends toward the blade platform for
approximately 20 mm.
Refer to the AMM for precise area.
Other airfoil areas :
- This is the remaining area of the blade that does not
include areas E and G.
Note : Defects should be classified in terms of criticality.
Defects seen in one area can be more critical than the
same defects seen in another.
(-5A, -5B, -5C, -7B) :
Blade locks :
Each booster rotor stage has blade locks. Experience has
shown that they sometimes work loose and, therefore,
should also be inspected.
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