Figure 13-60.Repair of small holes in skin with a flush patch.
repair information. The repairs discussed next are
typical of most repairs.
FLUSH PATCH CLEAR OF INTERNAL
STRUCTURES.In areas that are clear of internal
structure, the repair is relatively simple to make. This
is especially true where there is an access door or
plate through which the rivets can be bucked. In
inaccessible areas, the flush patch may be made by
substituting blind rivets for standard rivets, where
permissible, and devising a means of inserting the
doubler through the opening.
One method, shown in figure 13-60, has a doubler
that has been split. To insert the doubler, slip the split
edge under the skin and twist the doubler until it slides
in place under the skin. The screw in the center of the
doubler is temporarily installed to serve as a handle
for inserting the doubler through the hole. This type
of patch is normally recommended for holes up to
1 1/2 inches in diameter. In holes larger than
1 1/2 inches, trim a hole to a rectangular or elliptical
shape and round the corners to a generous radius. See
Figure 13-61.Flush rectangular patch.