TOMARK, s.r.o.
Airplane Maintenance Manual
Chapter 51 Standard Practices Structure
Issue: 28.FEB 2017
Page 149
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If the damaged area is located near the spars and frames, choose
such patch dimension so that it covers all these elements of structure
and it is possible to rivet it (Figure 29).
Types of patches, according to their position on the airframe
structure:
Surface patches - These can be used in the areas where surface
smoothness is not important
Sunk patches - Use for patches on the wing, tail unit and control
surfaces.
Surface patches across obstacles and stiffeners in the skin - pay
special attention to drilling the patch together with the surrounding
structure. Attach the patch in several points and then drill holes for
rivets from inner side (if possible). Use original holes in frames and
stiffeners.
Figure 29
Repair of the punctured skin in the frame area