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Edition – Rev 0
51-20
DAMAGE CLASSIFICATION AND REPAIRS - GENERAL
51-20 DAMAGE CLASSIFICATION AND REPAIRS
This section deals with the procedure allowing for assessing damage and for choosing
consequently the repair method, if permitted.
STEP 1: STRUCTURE EXAMINATION
The damage classification starts with the examination of the structure.
Visual inspection is the most common form of inspection for aircraft. This inspection
procedure may be greatly enhanced by the use of appropriate combinations of
magnifying instruments, borescopes, light sources, video scanners, and other devices as
applicable.
Visual inspection provides a means of detecting and examining a wide variety of
component and material surface discontinuities, such as cracks, corrosion,
contamination, surface finish, weld joints, solder connections and adhesive disbonds.
Visual inspection is widely used for detecting and examining aircraft surface cracks,
which are particularly important because of their relationship to structural failures.
As general rule
Clean the areas or surface of the parts to be inspected. Remove any
contaminates that might hinder the discovery of existing surface
indications. Do not remove the protective finish from the part or area prior
to inspection. Removal of the finish may be required at a later time if other
inspection techniques are required to verify any visual indications of flaws
that are found.
Perform a preliminary inspection of the overall general area for
cleanliness, presence of foreign objects, deformed or missing fasteners,
security of parts, corrosion, and damage.
If the configuration or location of the part conceals the area to be inspected, use visual
aids such as a mirror or borescope.
Namely, examine the structure for:
– buckled, bulging, or dented skin;
– surface discontinuities as cracks and buckling, scores and scratches, drawn rivet
and bolt holes, delamination of composites.
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