FAA Advisory Circular 43.13-1B
Acceptable Methods, Techniques, and Practices
Aircraft Inspection and Repair
AC 43.13-1B | 4. Metal Structure, Welding, and Brazing | 5. Welding and Brazing | 4-96. Splicing Tubing by Outer-Sleeve Method
9/27/01
AC 43.13-1B CHG 1
FIGURE 4-36. Welded patch repair.
b. If the inner sleeve fits very tightly in the
replacement tube, chill the sleeve with dry ice
or cold water. If this is insufficient, polish
down the diameter of the sleeve with emery
cloth. Tack the outer and inner replacement
tubes using rosette welds. Weld the inner
sleeve to the tube stubs through the 1/8-inch
gap, forming a weld bead over the gap.
4-96. SPLICING TUBING BY OUTER
SLEEVE METHOD. If partial replacement
of a tube is necessary, make the outer-sleeve
splice using a replacement tube of the same di
ameter. Since the outer-sleeve splice requires
the greatest amount of welding, it should be
used only when the other splicing methods are
not suitable. Information on the replacement
by use of the outer-sleeve method is given in
figure 4-38 and figure 4-39.
a. Remove the damaged section of a tube
utilizing a 90-degree cut. Cut a replacement
steel tube of the same material, diameter, and
at least the same wall thickness to match the
length of the removed portion of the damaged
tube. This replacement tube must bear against
the stubs of the original tube with a total toler
ance not to exceed 1/32 inch. The outer-sleeve
tube material selected must be of the same
material and at least the same wall thickness as
the original tube. The clearance between inside
diameter of the sleeve and the outside diameter
of the original tube may not exceed 1/16 inch.
b. From this outer-sleeve tube material, cut
diagonally (or fishmouth) two sections of tub
ing, each of such length that the nearest end of
the outer sleeve is a minimum distance of
1-1/2-tube diameters from the end of the cut
on the original tube. Use a fishmouth sleeve
wherever possible. Deburr the edges of the
sleeves, replacement tube, and the original
tube stubs.
c. Slip the two sleeves over the replacement
tube, align the replacement tube with the origi
nal tube stubs, and slip the sleeves over the
center of each joint. Adjust the sleeves to suit
the area and provide maximum
reinforcement.
d. Tack weld the two sleeves to the re
placement tube in two places before welding.
Apply a uniform weld around both ends of one
of the reinforcement sleeves and allow the
weld to cool; then, weld around both ends of
the remaining reinforcement tube. Allow one
sleeve weld to cool before welding the re
maining tube to prevent undue warping.
Par 4-95
Page 4-67