FAA Advisory Circular 43.13-1B
Acceptable Methods, Techniques, and Practices
Aircraft Inspection and Repair
AC 43.13-1B | 3. Fiberglass and Plastics | 2. Metallic Sandwich Secondary Structure Repairs | 3-10. Repairs to Metallic Sandwich Secondary Structure
AC 43.13-1B
FIGURE 3-10. Typical types of core replacement.
9/8/98
fastened. Figure 3-12 shows a cross-section of
a typical bonded and mechanically fastened re
pair. The damaged area may or may not need
to be filled.
(1) Bonded overlap repairs work well
on most structures. The overlap repair consists
of a solid patch material such as metal, pre
cured laminates, prepreg or wet layup material
co-cured in place.
(2) Bolt or blind rivet. Mechanically
fastened, bolted, or blind rivet repairs are pri
marily used for thick structures. Primary con
cerns include bolt/rivet spacing, fastener di
ameter, number of fasteners, and sealant type.
g. Core potting is the process of filling
the core cutout with a curable paste filler mate
rial. If the damage is sustained in an area with
an already-potted core, the replacement core
should also be potted. In other cases, if the
honeycomb or foam core is damaged, it may
be potted rather than plugged if the damaged
area is small (1 inch or less). Remove the face
sheet with a power router, using a router tem
plate to prevent injury to undamaged face skin.
The router may be adjusted to remove one of
the face skins only, a face skin and part of the
core, a face skin and all of the core, or both the
face skins and the core. (See figure 3-13.)
FIGURE 3-11. Typical undercut core material cavity.
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