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 | 4-97. Splicing Using Larger Diameter Replacement Tubes
AC 43.13-1B CHG 1
9/27/01
FIGURE 4-37. Splicing by inner-sleeve method.
4-97. SPLICING USING LARGER DI
AMETER REPLACEMENT TUBES. The
method of splicing structural tubes, as shown
in figure 4-40, requires the least amount of
cutting and welding. However, this splicing
method cannot be used where the damaged
tube is cut too near the adjacent cluster joints,
or where bracket-mounting provisions make it
necessary to maintain the same replacement
tube diameter as the original. As an aid to in
stalling the replacement tube, squarely cut the
original damaged tube leaving a minimum
short stub equal to 2-1/2-tube diameters on one
end and a minimum long stub equal to
4-1/2-tube diameters on the other end. Select a
length of steel tube of the same material and at
least the same wall thickness, having an inside
diameter approximately equal to the outside
diameter of the damaged tube. Fit this re
placement tube material snugly around the
original tube with a maximum diameter differ
ence of 1/16 inch. From this replacement tube
material, cut a section of tubing diagonally (or
fishmouth) of such a length that each end of
the tube is a minimum distance of 1-1/2-tube
diameters from the end of the cut on the origi
nal tube. Use a fishmouth cut replacement
tube wherever possible. Deburr the edges of
the replacement tube and original tube stubs.
If a fishmouth cut is used, file out the sharp ra
dius of the cut with a small round file.
Page 4-68
Par 4-97