![]() | COMMERCIAL ENGINE STANDARD PRACTICES MANUAL | Dated: 02/26/2018 |
SPM 70-33-03 SPECIAL INSPECTION FOR SURFACE FRETTING OR GALLING | ||
TASK 70-33-03-220-006 |
1 . | General. |
The inspection of fretting or galling on surfaces requires special techniques to determine serviceability. The nature of these defects(refer to definitions in TASK 70-30-00-200-001, Inspection Methods) makes the assessment of the damage difficult. Due to this difficulty, the following method may be used, when referenced by the Engine/Shop Manual for a specific part. |
2 . | Materials. |
Subtask 70-33-03-220-061 |
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3 . | Procedure. |
Subtask 70-33-03-220-062 |
A. | Initial Inspection. |
Visually determine the boundaries of the affected area and inspect as follows: |
(1) | Survey the entire affected area with a 0.03 inch (0.8 mm), radius scriber. Move the scriber in a random motion. Use feel, not sight, to determine if the affected area has a change in the surface when compared to the adjacent unaffected area resulting in increased roughness. |
(2) | If a change cannot be felt with the scribe, the area is serviceable; if a change can be felt, see paragraph B. |
B. | Cleanup of Area. |
(1) | Using an abrasive stick, rub the affected area briskly to remove any deposited material buildup. The abrasive stick is indicated in Subtask 70-33-03-220-061, Materials. |
(2) | Brush the area clean of any residue and see paragraph C. |
C. | Glass Inspection. |
(1) | Using a 3-7X glass and bright light, inspect the cleaned area for missing material. |
NOTE: |
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(2) | If missing material is not evident the part is serviceable; if missing material is evident, see paragraph D. |
D. | Final Inspection. |
(1) | Using a 0.03 inch (0.8 mm) radius scriber, inspect the area (reference Subtask 70-33-03-220-061, Materials.). |
(2) | If a change cannot be felt, the part is serviceable. If a change is felt, the part is not serviceable. Refer to Engine/Shop Manual for part disposition. |