TOMARK, s.r.o.
Airplane Maintenance Manual
Chapter 51 Standard Practices Structure
Page 148
Issue: 28.FEB 2017
▶
Place patches on the wing so, that the longer patch side lies in
direction of transversal axis of the aircraft (parallel to the wing
leading edge).
Figure 28
Location of patches on the airplane skin
▶
Mark the damaged surface area (preferably by spirit felt tip) and cut
out the most suitable geometrical shape (circle, square, rectangle).
▶
Be careful that all cracks as well as adjacent corroded areas are cut
out.
▶
Corners of cut out holes in the skin must have minimum radius of
12.7 mm (0.5 in) and their edges must be smoothly filed off.
Size of patch overlapping depends on the cut out of skin area:
Patch up to the area of 51.6 cm
2
- rivet by one row of rivets, the patch
edge must overlap the edge of the cut out hole by minimum 19 mm
(0.75 in).
Patch with the area over 51.6 cm
2
- rivet by two rows of rivets, the
patch edge must overlap the cut out hole by minimum 32 mm (1.25
in).
Both ways of patching are shown on Figure 28.
