CFM CFM56-2 - Possible Defects in the DAC Dome Area; Possible Defects on the DAC Outer and Inner Liners

EFFECTIVITY
ALL CFM56 ENGINES
CFMI PROPRIETARY INFORMATION
CFM56-ALL TRAINING MANUAL
COMBUSTION
CHAMBER
BORESCOPE
INSPECTION
Page 122
Sep 03
COMBUSTION SECTION
(-5B, -7B) :
Possible defects in the DAC dome area.
Whenever the combustion chamber is inspected, the
following defects should be assessed with the AMM
serviceability limits :
- Cracks, or tears.
- Erosion.
- Distortion of internal parts.
- Missing material.
- Dirt buildup.
- Burn-through holes.
- Flaking of Thermal Barrier Coating (TBC).
Possible defects on the DAC outer and inner liners.
Carbon deposits are often misinterpreted as defects
(holes, burn-through, cracks, etc.). Use the high
magnication probe, and higher light intensity to conrm
the type of defect.
The aft panel of the inner liner is susceptible to distortion
and cracking. The rst evidence of this is a discoloration
in a round spot approximately the size of a large dilution
hole, which is followed by distortion and cracking. This
usually occurs uniformly around the liner.
TOC